However, I am starting to do more philosophy blogging over at my main blog, The View from the Foothills. Consequently, those few of you who still have this blog on your feed readers and who were kind enough to encourage me in past years might want to look over there instead.

Thanks!

Heraclitus surprised me. Copleston spends a fair amount of time on him, and frankly he sounds a lot more like a mystic than a philosopher. He says that Fire is the “ur-stuff” of which everything else is made, but he seems to say this almost on metaphorical rather than physical grounds.

As for Aristotle, I was surprised. Usually I find Thomas’ commentary more understandable that Aristotle’s text, but this time it was the other way around. (Of course, I might be fooling myself.) In any event, it appears that my conjecture was correct. When Aristotle talks of three principles, a pair of contraries and a substrate, he’s not say that everything we see derives from a single pair of contraries and a single substrate–not everything need be Fire. Instead, he’s saying that in every coming-to-be, there’s something that comes to be, the subject to which it happens, and its opposite.

And if it’s latter, which makes much more sense to me, how do these three principles relate to the four causes?

I can understand the need for contraries. I see a white thing; and it becomes a black thing. It was white, and now it’s black. These are contraries. To change means to be different, to be now A and then not-A. So far, so good. And I can see why you need something underlying A and not-A that remains through the change. (At least, I think I do; I might be fooling myself.)

But I don’t really understand the relationship between contrarieties and genera, or why there can only be a single primary contrariety in a genus, or how one pair of contraries can necessarily reduce to another pair, or how all things that are can be generated from one kind of “stuff” and one pair of contraries. That seems too simple.

Can anyone help me out with this?

In addition, I read Copleston’s chapter on the Pythagoreans, who are interesting to me on two grounds. First, unlike the Miletians, they had the notion of an immortal soul and believed in transmigration of souls. This appears to be an innovation in Greek thought. I’ll also note that it’s not completely clear just what they thought the soul was, only that it was what gave the person identity and that it was more important than the body. Second, they described the universe in terms of Number and Geometry. They attached mystical significance to particular numbers; but they seemed to be inspired in this by the amazing ways you can use numbers to describe what is. They were especially taken with the relationship between lengths of harp strings and the tones they produce. Apparently they mostly thought of numbers geometrically; for example, the number 9 is a square number, and thus can be thought of as filling an area.

Onward!

I’ve been working slowly through the first book of Aristotle’s Physics, which I think is the most challenging work I’ve ever seriously tried to get to grips with. I’m doing so with the aid of Aquinas’ commentary on the Physics; Dumb Ox Books has a nice paperback edition of it. It’s broken into “lectures”; each lecture consists of a passage from the Physics followed by Aquinas’ commentary. This is a nice format, as it means I can spend time reading and reflecting on Aristotle’s words…and then, and only then, go and see what Thomas has to say. Aristotle is extremely terse, and Thomas is very good at providing background and drawing out hidden assumptions.

Today I began looking at Lecture 11, which looks at Book I, chapter 6 of the Physics. Here Aristotle continues a discussion of the “principles” of the things we see around us: there are many things in this world, but there must be something underlying them. What is this underlying stuff? Is there one principle or many? And if many, how many? Some have said there there One principle; others have said two principles which are contraries; others have said there are many or even infinite principles.

Aristotle has already shown that there can’t simply be one principle of natural beings; here he argues (using probable arguments rather than demonstrations) that there are three: a primary contrariety (a pair of contraries, with their intermediate states), and some kind of substrate, something that can change.

He frequently makes the argument that in a single genus there can be but one primary contrariety; all other contrarieties in that genus must be reducible to the primary. And after some reflection, this seems to be to be a matter of definition; you’ve got some basic kind of thing, and in each genus you slice it up in some particular way. That’s the primary contrariety.

A genus is made up of species (which are frequently genera in their own right), and each species is distinct from the others. The species in a genus are in fact contraries; in mathematical terms I’d refer to them as disjoint sets. But Aristotle seems to be assuming more than that: that the primary contrariety is defined by a pair of opposites, as though all species in the genus must by definition be positioned along a spectrum from the one to the other. Is this necessarily the case? And if so, why? Is this a necessary corollary of essentialism?

I’m not yet done with Lecture 11; some of Aristotle’s comments toward the end of the chapter are extremely opaque to me, and I’ve not yet worked my way through all of Aquinas’ comments on them.

When I’d ground to a halt on the Physics, I moved on to something a little lighter for the rest of my study time: Frederick Copleston’s History of Philosophy, which I just recently discovered. I’ve just started reading the first volume, on Greek and Roman philosophy, and as I expected I’m finding it a great adjunct to the Physics. Different people learn in different ways; what’s working for me is to delve deeply into one thing (the Physics) while reading widely but shallowly in the same general vicinity. In this way I see the same topics approached from different directions, in different words, and one author often states clearly what another author states elliptically or obscurely. More than that, you can’t study everything in depth; reading widely provides needed context.

At present, Copleston is discussing the Ionian school of philosophers; so far I’ve read about Thales and Anaximander. Thales was the first we know of to discover the principle that Copleston terms “Unity in Differences”: that underlying all of the many things we see around us, there must be some principle that they all share. Thales though that it was Water, which as Copleston remarks has more plausibility than you might think: Water evaporates, thus seeming to change into Air, and freezes, thus become solid and in some sense Earth.

Anaximander goes beyond this, making the point, in fact, that Aristotle serendipitously makes in the passage of the Physics I was studying today. There must be contraries: things change from this to that. But there must be something underlying this that doesn’t change. It can’t be Water or Fire, for these are contraries. Anaximander called this underlying primitive “stuff” the Boundless Infinite.

All for now.

On a materialist account of mind, the brain is something like a computer, and the mind is something like software running on that computer. This is the fundamental principle for folks pursuing Strong AI: we know, they say, that it’s possible; all that’s left is to work out the engineering details. But anyway, I took what I know about software, and started trying to apply it to the mind, on the assumption (yes, I’m playing Devil’s Advocate, here) that the brain is a computer and the mind is simply the software running on it.

In this view, a concept must be something represented in the brain, say in the form of neuronal firing patterns. As such, it’s effectively data: either a program executed directly upon the brain’s hardware, or data operated upon by some program that executes directly upon the brain’s hardware.

Now let’s switch gears, and consider a statement written in a programming language—Tcl, say.

    set pi 3.14159

• The efficient cause of the statement is the programmer. That would be me.
• The material cause of the statement is the source code, entered in a file on a computer or written on paper: a sequence of characters.
• The formal cause of the statement is its syntax: that which dictates how the characters are arranged to be valid Tcl code.
• The final cause of the statement is its semantics: what it’s supposed to do.

Feser points out that the efficient cause and the final cause are always linked. In this case, the link is obvious. I wrote the line of code because I wanted the final cause: in this case, to assign the value 3.14159 to the variable “pi”.

Now, what gives the statement its semantics? There are two answers to that question.

First, the semantics are defined by the program that executes the statement: the Tcl interpreter. When the interpreter reads executes the statement set pi 3.14159, it does something like the following:

• The first word of the statement is the command, set.
• The first argument to set is a variable name.
• Create the variable if it does not exist.
• The second argument to set is a value.
• Assign the value to the variable, replacing any previous value.

Second, I do. I want to express that the value 3.14159 should be assigned to the variable “pi”, and that statement means that operation to me. In other words, Tcl is an intelligible language whether a program that interprets exists or not.

But consider the Tcl interpreter again. It gives the statement its meaning, its semantics. But how does it do this? The Tcl interpreter is itself a computer program. The set command is defined as a function in a programming language called C. Each statement in the function is written in the C language, and has its own semantics; the collection of the statements implement the semantics given above.

The efficient cause of the set is another programmer (a man named John Ousterhout, as it happens); and the semantics are what he intended, but also the semantics of the C language.

The thing to note, here, is that a statement in a programming language, or an entire program, has semantics—meaning—only in the context of an interpreter: the Tcl interpreter, the C compiler, the microprocessor, the mind of the programmer.

One could continue to trace the semantics back along a number of branches. The Tcl interpreter is written in C, but the C code is compiled into machine language; at run time, the machine language is interpreted by the microprocessor. And the machine language has semantics. The C code is given its semantics by the C compiler, which is also a C program that compiles to machine code. There are programs interpreting programs interpreting programs, all of them ultimately running on a piece of hardware; and each program and the hardware itself were all designed and implemented by a human being.

In short, program semantics ultimately come from people.

The efficient cause of the semantics of a program is the programmer who wrote.

The final cause of the semantics is what the programmer wants the program to do.

Now, let’s switch back to the mind, once again from the materialist point of view. A concept is like a statement in a programming language. It has some representation: neuronal firings instead of a bit pattern. And it has meaning, or it isn’t a concept. It has semantics.

So where did the semantics come from?

As we’ve seen in the case of a computer program, the semantics ultimately comes from the programmer—and, though I haven’t developed the idea above, the end user. That is, from people. So the semantics of the program in my head must come from people. That is, from outside.

And yet, the concepts in my head clearly have meaning to me. It’s absurd to think that they don’t.

I’m not sure where to go from here, but it certainly strikes me as absurd that a program can give itself meaning, which implies that I am not a program.

In the previous chapter, Thomas argues that the divine goodness is the ultimate end of all created things.  In this chapter he builds on this, showing that the divine goodness is the reason for the diversity of things: as the divine goodness is infinite, it takes a diversity of things to express it.  Thomas says,

Moreover, a perfection existing in a universal cause simply and in a unified manner, is found to be multiple and discrete in the effects of that cause. For a perfection has a nobler existence in a cause than in its effects. But the divine goodness is one, and is the simple principle and root of all the goodness found in creatures. Hence creatures must be assimilated to the divine goodness in the way that many and distinct objects are assimilated to what is one and simple. Therefore multiplicity and distinction occur in things not by chance or fortune but for an end, just as the production of things is not the result of chance or fortune, but is for an end. For existence, unity, and multiplicity in things all come from the same principle.

As we discussed previously, an effect cannot be greater (here, “nobler”) than its cause.  But some goodness in the cause (here, a “perfection”) must be expressed in the effect (a cause can only give what it has) and in fact can be expressed in its effects multiple ways.  Now, as the creator and ultimate end of all created things, God is both the efficient cause and the final cause of all things; and so all created things must reflect the perfection of God. 

The distinction among things is not caused by matter; for things were originally constituted in being by creation, which does not require any matter. Moreover, things which issue purely from the necessity of matter have the appearance of being fortuitous.

What a fascinating little paragraph.  An atheist would say that the diversity in things is precisely the result of material processes, culminating in biological evolution.  But Thomas rejects this.  The question is, is he rejecting evolution per se, or merely a purely materialistic account of it?  It’s certainly true that evolution has “the appearance of being fortuitous”.  In any event, there’s no real conflict between Creation and Evolution, any more than there is a conflict between statements, “Grass is green because God made it so” and “Grass is green because it contains chlorophyll.” 

Furthermore, multiplicity in things is not explained by the order obtaining among intermediate agents, as though from one, simple first being, there could proceed directly only one thing that would be far removed from the first being in simplicity, so that multitude could issue from it, and thus, as the distance from the first, simple being increased, the more numerous a multitude would be discerned. Some have suggested this explanation. But we have shown that there are many things that could not have come into being except by creation, which is exclusively the work of God, as has been proved. Hence we conclude that many things have been created directly by God Himself.

In other words, God needs no demi-urge, as many of the gnostics held.

I wonder what’s in the set of things that could not have come into being except by creation; and how that differs from what Thomas thought was in that set of things.

It is likewise evident that, according to the view under criticism, the multiplicity and distinction among things would be fortuitous, as not being intended by the first agent. Actually, however, the multiplicity and distinction existing among things were devised by the divine intellect and were carried out in the real order so that the divine goodness might be mirrored by created things in variety, and that different things might participate in the divine goodness in varying degree. Thus the very order existing among diverse things issues in a certain beauty, which should call to mind the divine wisdom.

There are two significant propositions here:

• All things in creation participate in the divine goodness
• They do so because they were created in their multiplicity for this purpose.

If we hold that dogs and cats evolved from some common (though very remote) ancestor, then, Thomas seems to say that dogs do not reflect the divine goodness particularly in their dogginess and that cats do not reflect the divine goodness particularly in their felinity, because those things were not created directly.  Personally, I’d think that the first bullet is true, but that the second is too limiting; things are more complicated than Thomas knew.

Has anyone attempted a synthesis of Thomism and evolution?

The ultimate end of things is necessarily the divine goodness. For the ultimate end of things produced by one who works through his will is that which is chiefly and for its own sake willed by the agent. It is for this that the agent does all that he does. But the first object willed by the divine will is God’s goodness, as is clear from a previous discussion. Hence the ultimate end of all things made by God must necessarily be the divine goodness.

To what end did I get in my car this morning? To the end of driving to work. But why did I drive to work? To work on my project. But why work on my project? Because it’s fun, and to that extent it is an end in itself; but mostly because I am paid. And I want to be paid so that I can support myself and my family. And that is the ultimate end of my getting in the car this morning: that which I will for its own sake.

So what is the ultimate end of all created things? It is the ultimate end to which their Creator created them, and that is the end what their Creator willed for its own sake. And per a previous discussion, what God wills first and foremost is His goodness.

But as usual, Thomas isn’t content to leave it at this. He continues,

Furthermore, the end of the generation of everything that is generated is its form. Once this is achieved, generation ceases.

To generate a thing is to bring it into existence, to make it come to be. Creation ex nihilo is one way; reproduction is another; an artisan’s work is another. Now, a thing is what it is by virtue of its form, its essence. Suppose I’m sculpting a bust of someone: I am quite literally taking a block of clay and giving it form, the form of the person I’m sculpting. Once I have given it this form, the bust exists: it has come to be.

Thus, it’s reasonable to say that the end of bringing something into existence is its form; because its form is what it is, and what it is is what its creator wanted to create.

OK; what of it?

For everything that is generated, whether by art or by nature, is in some way rendered similar to the agent in virtue of its form, since every agent produces an effect that has some resemblance to the agent himself. Thus the house that is realized in matter proceeds from the house existing ideally in the mind of the architect. In the realm of nature, likewise, man begets man.

This is a notion I’ve been struggling with: that every effect is like unto its cause. In short, everything an agent causes to be or to happen reflects the nature of that agent in some way. This doesn’t seem self-evidently true to me, but Thomas takes it as a given. I don’t think I really understand the principle completely, though; I’ve not seen any detailed discussion of it.

Anyway, it seems somewhat plausible, at least in the cases Thomas lists. Nothing can come from nothing. Artifacts begin in the mind of the artisan. Children come from parents. And there is a resemblance in that way between the object conceived and the object(s) that conceived it.

Apparently, the likeness can be somewhat attenuated:

And if anything that is generated or effected by natural processes is not like its generating cause according to species, it is at any rate likened to its efficient causes as imperfect to perfect. The fact that a generated product is not assimilated to its generating cause according to species, is explained by its inability to rise to perfect likeness with its cause; but it does participate in that cause to some extent, however imperfectly.

I can (with help!) conceive a son, who resembles me perfectly to the extent of being of exactly the same species; but I can also (in theory, if not in practice) sculpt a statue that resembles me but is not alive. It lacks a perfection that I have, even though it might resemble me closely; it relates to me as imperfect to perfect. The opposite, apparently, cannot happen: the statue cannot conceive a living copy.

This occurs, for example, in animals and plants that are generated by the power of the sun.

I will skip over the medieval biology.

Hence in all things that are made, the end of their generation or production is the form of their maker or generator, in the sense that they are to achieve a likeness of that form.

Since the end of the generation of a thing is its form, and since this form resembles that of the thing’s maker, perfectly or imperfectly, it’s reasonably to see that the end of the generation of a thing is the form of its maker.

I’m not sure I buy that, entirely; consider the architect: yes, the finished house (if competently designed and built) matches the form the architect had in mind; but does it match the architect’s own form? I suppose in the sense that it’s human scale, designed for humans to live in; but in that case, make it a doll house, or a dog house.

But the form of the first agent, who is God, is nothing else than His goodness.

And therefore, the end of all that God creates is His goodness. But why is God’s form His goodness, rather than His truthfulness or His beauty (or His existence)? I suppose because Goodness is the category of value that’s relevant to the Will, and thus to final causes.

But what does it mean that “the end of all that God creates is His goodness”?

This, then, is the reason why all things were made: that they might be assimilated to the divine goodness.

All comes from Him; all flows back. Except for human beings, who gloriously (and sometimes tragically) have a choice about it.

I guess you can’t be sublime on a schedule.

We showed above that God has brought things into existence, not through any necessity of His nature, but by His intellect and Will. Any agent that works in this way, acts for an end: the end is a principle for the operative intellect. Accordingly everything that is made by God necessarily exists for an end.

An entity that acts of necessity has no choice, and acts to no purpose of its own. If I throw a rock, and it hits a window, the window breaks; but the rock had no intention of breaking the window, or even of flying through the air. It’s a rock; it has no choice. But if I choose to pick up a rock, and throw it so that it breaks a window, then I must have some end in view. Perhaps I want to break the window, so as to break into the house. Perhaps I’m simply killing time, and broke the window accidentally. Either way, I threw the rock for a reason. And so, also, with God. Every act of creation is an act of God’s will, and there is a reason for it.

Moreover, things were produced by God in a supremely excellent way; for the most perfect Being does everything in the most perfect way. But it is better for a thing to be made for an end than to be made without the intention of achieving an end; for the goodness that is in things which are made comes from their end. Hence things were made by God for an end.

It is better to have a purpose than to be purpose-less; and since God always acts in the most perfect way, all He creates will have a purpose.

It seems to me, though, that there’s no particular reason why we should know what that purpose is. What’s the purpose of banana slugs? Though, of course, it’s fun to speculate.

An indication of this is seen in effects produced by nature. None of them is in vain, all are for an end. But it is absurd to say that things produced by nature are in better order than is the very constituting of nature by the first Agent, since the entire order of nature is derived from the latter. Clearly, therefore, things produced by God exist for an end.

This is an interesting assertion, given that many people these days would assert, equally confidently, that nothing in nature acts for an end. That’s clearly wrong, in my view; some things in nature clearly act for an end. Eyes are pretty clearly for seeing, for example. But is it so obvious that everything in nature acts for an end? I dunno.

It’s important to remember that matter, for Thomas, is not quite what we mean by the term. Matter is simply that which changes. When you eat food, the food is assimilated and becomes part of your body. There was a hot-fudge sundae; there is a new wideness about the middle. Clearly the sundae ceased to be; clearly I increased in being; but something must have changed from the one to the other, and that something is what Thomas calls matter.

Anyway, let’s let Thomas talk.

However, even though finished products were not in existence from eternity, we might be inclined to think that matter had to exist from eternity. For everything that has being subsequent to non-being, is changed from non-being to being. Therefore if created things, such as heaven and earth and the like, did not exist from eternity, but began to be after they had not been, we must admit that they were changed from non-being to being. But all change and motion have some sort of subject; for motion is the act of a thing existing in potency.

If you’ve got a dog, the dog came to be at some point; it changed from non-being to being. But in every change, there must be some subject to change. In the case of something coming to be, what’s the subject of the change?

However, the subject of the change whereby a thing is brought into existence, is not the thing itself that is produced, because this thing is the terminus of the motion, and the terminus and subject of motion are not the same. Rather, the subject of the change is that from which the thing is produced, and this is called matter.

Before the dog came to be, there was no dog. And yet the dog came to be out of something; and this something is matter. The dog’s mother ate food, and breathed air, and the matter she took in was transformed by her body into the body of her puppy. Matter came in, and a new dog came out.

Accordingly, if things are brought into being after a state of non-being, it seems that matter had to exist prior to them. And if this matter is, in turn, produced subsequent to a period of non-existence, it had to come from some other, pre-existing matter. But infinite procession along these lines is impossible. Therefore we must eventually come to eternal matter, which was not produced subsequent to a period of non-existence.

So before something can come to be, you have to have some matter to start with. And in turn, that matter had to come to be; and since you can’t have an infinite regression, it would appear, saith the objector, that some matter must have existed eternally.

Thomas will answer this objection presently; but in the mean time he moves on to the second.

Again, if the world began to exist after it had first not existed, then, before the world actually existed, it was either possible for the world to be or become, or it was not possible. If it was not possible for the world to be or to become, then, by equipollence, it was impossible for the world to be or to become. But if it is impossible for a thing to become, it is necessary for that thing not to become. In that case we must conclude that the world was not made. Since this conclusion is patently false, we are forced to admit that if the world began to be after it had first not been, it was possible for it to be or to become before it actually existed.

All change brings some potency into actuality. If the world did not exist, and then came to exist in actuality, it must first have existed in potency. But that potency must have been in matter:

Accordingly there was something in potency with regard to the becoming and being of the world. But what is thus in potency to the becoming and existence of something, is the matter of that something, as we see exemplified in the case of wood relative to a bench. Apparently, therefore, matter must have existed always, even if the world did not exist always.

So how does Thomas answer these objections?

As against this line of reasoning, we showed above that the very matter of the world has no existence except from God. Catholic faith does not admit that matter is eternal any more than it admits that the world is eternal. We have no other way of expressing the divine causality in things themselves than by saying that things produced by God began to exist after they had previously not existed. This way of speaking evidently and clearly brings out the truth that they have existence not of themselves, but from the eternal Author.

In short, creation ex nihilo, from nothing, is a special case. A thing created ex nihilo is not created from pre-existing matter; it simply comes to be where before there was nothing.

As for the objector’s argument, he’s right about the nature of change; but creation ex nihilo is not change.

The arguments just reviewed do not compel us to postulate the eternity of matter, for the production of things in their totality cannot properly be called change. In no change is the subject of the change produced by the change, for the reason rightly alleged by the objector, namely, that the subject of change and the terminus of the change are not identical. Consequently, since the total production of things by God, which is known as creation, extends to all the reality that is found in a thing, production of this kind cannot properly verify the idea of change, even though the things created are brought into existence subsequently to non-existence. Being that succeeds to non-being, does not suffice to constitute real change, unless we suppose that a subject is first in a state of privation, and later under its proper form. Hence “this” is found coming after “that” in certain things in which motion or change do not really occur, as when we say that day turns into night. Accordingly, even though the world began to exist after having not existed, this is not necessarily the result of some change.

What he said.

In fact, it is the result of creation, which is not a true change, but is rather a certain relation of the created thing, as a being that is dependent on the Creator for its existence and that connotes succession to previous non-existence. In every change there must be something that remains the same although it undergoes alteration in its manner of being, in the sense that at first it is under one extreme and subsequently under another. In creation this does not take place in objective reality, but only in our imagination. That is, we imagine that one and the same thing previously did not exist, and later existed. And so creation can be called change, because it has some resemblance to change.

It looks kind of like change, but it isn’t.

The second objection, too, lacks cogency. Although we can truly say that before the world was, it was possible for the world to be or to become, this possibility need not be taken to mean potentiality.

That is, it was possible for the world to come to be, but that doesn’t mean that there was any potency in place.

In propositions, that which signifies a certain modality of truth, or in other words, that which is neither necessary nor impossible, is said to be possible. What is possible in this sense does not involve any potentiality, as the Philosopher teaches in Book V of his Metaphysics [12, 1019 b 19].

Are unicorns possible? Certainly; there’s no reason why there couldn’t be a horse-like being with a single horn. But on the other hand, there’s no reason to think that the potentiality for the birth of a unicorn actually exists in the world today.

However, if anyone insists on saying that it was possible for the world to exist according to some potency, we reply that this need not mean a passive potency, but can mean active potency; and so if we say that it was possible for the world to be before it actually was, we should understand this to mean that God could have brought the world into existence before He actually produced it.

As I noted some chapters ago, there are two kinds of potency, active and passive. The tree can be turned into timber; this is passive potency. The lumberjack can turn the tree into timber; this is active potency. Matter has passive potency, and agents have active potency. In creation, God is the agent. So if potency were strictly necessary, God provides the active potency, and no passive potency is required.

Hence we are not forced to postulate that matter existed before the world. Thus Catholic faith acknowledges nothing to be co-eternal with God, and for this reason professes that He is the “Creator and Maker of all things visible and invisible.”

A note on Thomas’ procedure. He is not trying to prove from first principles that the doctrines of the faith are true; he accepts them as revealed truth. Rather, he’s trying to show that the doctrines of the faith are not unreasonable, that is, not in obvious contradiction to those truths accessible to human reason.

We might imagine that, although God can produce a new effect by His eternal and immutable will, some sort of motion would have to precede the newly produced effect. For we observe that the will does not delay doing what it wishes to do, unless because of some motive that is operative now but will cease later, or because of some motive that is inoperative now but is expected to become operative in the future. In summer a man has the will to clothe himself with a warm garment, which, however, he does not wish to put on at present, but in the future; for now the weather is warm, although it will cease to be warm with the advent of a cold wave later in the year.

This is a nice explanation. My will is to put on warm clothing if I’m cold. That remains my will, even if I’m not currently cold and have no desire to put on warm clothing at the moment. Similarly, it’s my will that my children behave themselves at all times, not simply when I have my eye on them and am thinking about it.

I’ve usually thought of my will as being whatever I’m choosing at the moment, but it is clearly much more complicated than that. I’ll have to ponder that.

Anyway, the application is clear: God might wish for some effect to happen at one time but not another.

Accordingly, if God wished from eternity to produce some effect, but did not produce it from eternity, it seems either that something was expected to happen in the future that had not yet occurred, or else that some obstacle had to be removed that was then present. Neither of these alternatives can take place without motion. Thus it seems that a subsequent effect cannot be produced by a preceding will unless some motion previously occurs.

Now, isn’t that neat. It seems that God’s not the First Cause of things produced in time…because His will is waiting on something else to happen, which is therefore the real cause of the effect:

And so, if God’s will relative to the production of things was eternal, and nevertheless things were not produced from eternity, their production must have been preceded by motion, and consequently by mobile objects. And if the latter were produced by God, but not from eternity, yet other motions and mobile objects must have preceded, and so on, in infinite recession.

But an infinite recession is impossible, and so God can’t produce things in time. So the objector says.

The solution to this objection readily comes to mind if we but attend to the difference between a universal and a particular agent. A particular agent has an activity that conforms to a norm and measure prescribed by the universal agent. This is clear even in civil government. The legislator enacts a law which is to serve as a norm and measure. Any particular judge must base his decisions on this law.

OK; and presumably God is the universal agent.

Again, time is the measure of actions which occur in time. A particular agent is endowed with activity regulated by time, so that he acts for some definite reason now, and not before. But the universal agent, God, instituted this measure, which is time, and He did so in accord with His will. Hence time also is to be numbered among the things produced by God. Therefore, just as the quantity and measure of each object are such as God wishes to assign to it, so the quantity of time is such as God wished to mete out; that is, time and the things existing in time began just when God wished them to begin.

As the creator of time, God is not bound by it. This is yet another reminder that “eternity” is not the same as “endless time”.

The objection we are dealing with argues from the standpoint of an agent that presupposes time and acts in time, but did not institute time. Hence the question, why God’s eternal will produces an effect now and not earlier, presupposes that time exists; for “now” and “earlier” are segments of time.

Right. I choose to do this now, or I choose to do it later, but if I choose to do it later I have to wait until later. But God’s different. It’s rather like the difference between a cassette tape and a compact disk. CDs can be accessed randomly, but tapes can only be accessed sequentially. God can access time at any point He chooses.

With regard to the universal production of things, among which time is also to be counted, we should not ask: “Why now and not earlier?” Rather we should ask: “Why did God wish this much time to intervene?” And this depends on the divine will, which is perfectly free to assign this or any other quantity to time.

In a sense, time is like space, to God. I can put my computer down here or there; God can put things in time now or then, just as he chooses.

The same may be noted with respect to the dimensional quantity of the world. No one asks why God located the material world in such and such a place rather than higher up or lower down or in some other position; for there is no place outside the world. The fact that God portioned out so much quantity to the world that no part of it would be beyond the place occupied in some other locality, depends on the divine will. However, although there was no time prior to the world and no place outside the world, we speak as if there were. Thus we say that before the world existed there was nothing except God, and that there is no body lying outside the world. But in thus speaking of “before” and “outside,” we have in mind nothing but time and place as they exist in our imagination.

Yes. There’s no moment outside time, and there’s no place outside space, as we are capable of understanding the terms. A moment is an aspect of time, and a place is an aspect of space. And yet, God is clearly “outside” time and space in a very real sense. Which is clearly what Thomas refers to as an analogical use of the word. Cool.

The fact that God produces things by His will clearly shows that He can produce new things without any change in Himself. The difference between a natural agent and a voluntary agent is this: a natural agent acts consistently in the same manner as long as it is in the same condition. Such as it is, thus does it act. But a voluntary agent acts as he wills. Accordingly it may well be that, without any change in himself, he wishes to act now and not previously. For there is nothing to prevent a person from willing to perform an action later, even though he is not doing it now; and this without any change in himself. Thus it can happen, without any change in God, that God, although He is eternal, did not bring things into existence from eternity.

This is very true. I’ve had the intention all day to go out to dinner with a buddy this evening. It doesn’t require any changing of my mind to go do that. Actually going will require a change in my position and my posture, but not any change in my will.

Where God differs from me in this regard is first, that He makes things happen just by willing, and second, He has perfect knowledge. He can know, from all eternity, what He will will at any given point in time.

The truth set forth in the preceding chapter also discloses the fact that God has brought things into existence not through any necessity of His nature but by His will.

When Thomas says that something is necessary, he means that it couldn’t have possibly been otherwise. To say that a thing does something from the necessity of its nature is simply to say that it’s the thing’s nature to behave in such a way; the thing can’t help it. A stone is hard, and falls when it is dropped; it can’t help. It sounds odd to modern ears to say that a stone falls because it is its nature to do so; surely it falls because of gravity? But the Law of Gravity simply says that it is the nature of things that have mass to be attracted to other things that have mass proportionally to their mass.

God is not like this. He has created because He has chosen to create. How do we know this?

A single natural agent produces immediately but one effect, whereas a voluntary, agent can produce a variety of effects. The reason for this is that every agent acts in virtue of its form. The natural form, whereby a cause operates naturally, is limited to one for each agent. But intellectual forms, whereby an agent operates through his will, are many.

I’m not persuaded here. A stone, for example, simply lies there and does nothing, unless something else moves it. One agent, one effect. But a dog has no intellectual form, and can cause many effects. Can a dog be said to choose? Perhaps not. But perhaps I’m not understanding Thomas.

Therefore, since many things are immediately produced by God, as we have just shown, God evidently produces things by His will, and not under the impulse of natural necessity.

Why doesn’t this apply to a dog?

Besides, in the order of causes, an agent operating through intellect and will is prior to an agent operating by the necessity of its nature. For an agent operating through his will predetermines for himself the end for the sake of which he acts, whereas a natural cause operates on account of an end predetermined for it by another. But, as is clear from all that has gone before, God is the first agent. Hence He acts through His will, and not by a necessity of His nature.

An agent which acts by necessity has no choice in what it does; it is deterministic. Now, something caused it to do what it’s doing. That something is either also acting by necessity, or it is choosing to do what it’s doing. Ultimately, we get back to either God, the First Cause, or to some other intellect, as a true Secondary Cause.

Moreover, we demonstrated above that God is infinite in power. Consequently He is not determined to this or that effect, but is undetermined with regard to all effects.

Nothing can make God do anything. None of his actions are deterministic.

But what is undetermined regarding various effects, is determined to produce one of them by desire or by the determination of the will. Thus a man who is free to walk or not to walk, walks when he wills. Hence effects proceed from God according to the determination of His will. And so He acts, not by a necessity of His nature, but by His will.

This seems to be saying that actions are either free or determined, and that free actions must be chosen by a will. Since none of God’s actions are determined, He must have willed them.

This is why the Catholic faith calls the omnipotent God not only “Creator,” but also “Maker.” For making is properly the action of an artificer who operates by his will. And since every voluntary agent acts in virtue of the conception of his intellect, which is called his word, as we indicated above, and since the Word of God is His Son, the Catholic faith professes that “all things were made” by the Son.

Very nice.

The doctrine established above necessarily leads to the conclusion that things that cannot be brought into existence except by creation, come immediately from God.

Only God can create from nothing, and so anything that can only be created from nothing must be created by God. OK, I’ll buy that.

This, on the other hand, is clearly wrong:

Thus the heavenly bodies, as is manifest, cannot be produced except by creation. They cannot be said to be made from some preexisting matter, for then they would be capable of generation and corruption, and would also be subject to contrariety. But they are not, as their motion proves. For they move in circles, and circular motion has no contrary. Consequently the heavenly bodies were produced immediately by God.

Contraries are two propositions that cannot both be true. I do not see why circular motion has no contrary—the planet is at point A, and sometime later it is at point B; in fact, every point on the circle is the contrary of every other point. And, of course, we know now that the planets are bodies much like the Earth and subject to the same forces.

Just as an aside, C.S. Lewis has a neat book, The Discarded Image, which describes the image the average educated person would have had of the cosmos during the Midieval period.

Similarly the elements, regarded as complete units, do not come from any pre-existing matter. Anything that would thus pre-exist would have some form. And thus some body, other than the elements, would exist prior to them in the order of material cause. But if the matter existing prior to the elements had a distinct form, one of the elements would have to be prior to the others in the same order, supposing that the pre-existing matter had the form of an element. Therefore the very elements must have been produced immediately by God.

Here Thomas is speaking of the four elements, Air, Earth, Fire, and Water. But ignore that. The “elements” of any thing are the simplest beginnings of that thing. Euclid’s Elements, for examples, shows how all of plane geometry derives from the elements of geometry, a handful of definitions, axioms, and postulates. Consequently, the elements of matter are not Air, Earth, Fire, and Water, nor even the elements of the periodic table, but the most basic building blocks of which matter is constructed. When I was a kid, we might have said that these were protons, neutrons, and electrons; now we know that the situation is considerably more complicated. But whatever these smallest beginnings are, they are not made of anything else, or they wouldn’t really be the elements in the sense Thomas uses the word.

And these elements, since they cannot be produced from anything else in the material order, must necessarily then have been created by God. That’s rather cool.

It is even more impossible for incorporeal and invisible substances to be created by some one else, for all such substances are immaterial. Matter cannot exist unless it is subject to dimension, whereby it is capable of being marked off, so that many things can be made from the same matter. Hence immaterial substances cannot be made from pre-existing matter.

I’m not sure just what the argument is, here. Is Thomas saying that anything created of matter has dimension, that is, has a body, and consequently is corporeal?

In any event, I can’t see how you could make an immaterial substance out of matter, pre-existing or not.

Consequently they can be produced only by God through creation. For this reason the Catholic faith professes that God is the “Creator of heaven and earth, and of all things visible,” and also “of all things invisible.”

Yup, that we do.

However, we are not to imagine that the rational soul is derived from the substance of God, as some have erroneously thought. We demonstrated above that God is simple and indivisible. Therefore He does not join the rational soul to a body as though He had first severed it from His own substance.

Since God is indivisible, He can’t split bits of Himself to be souls.

Furthermore, we pointed out above that God cannot be the form of any body. But the rational soul is united to the body as the latter’s form. Hence it is not derived from the substance of God.

I don’t recall where Thomas proved this, and I’m too lazy tonight to look. But certainly, if God cannot be the form of any body, then it seems reasonable that a piece of God (if such could exist) can’t either.

Besides, we showed above that God is not moved either in Himself or by reason of some other thing that is moved. But the contrary of this is observed to take place in the rational soul, which is moved from ignorance to knowledge, from vice to virtue. Accordingly the soul is not of the substance of God.

And finally, God is eternal and unchanging, and the human soul is anything but unchanging.

Easy as pie, for a change.

This ultimate and complete form, the rational soul, is brought into existence, not by the power that is in the semen, but by a higher cause. For the power that is in the semen is a bodily power. But the rational soul exceeds the whole nature and power of the body, since no body can rise to the heights of the soul’s intellectual activity. Nothing can act in a way that surmounts its species, because the agent is nobler than the patient, and the maker excels his product. Hence the power possessed by a body cannot produce the rational soul, nor, consequently, can the energy inherent in the semen do so.

I don’t want to debate (or explore) Thomas’ understanding of human reproduction. The point is that the Rational Soul, have an intellectual, immaterial component, cannot be produced by material and bodily activity.

Thomas says, “…the agent is nobler than the patient, and the maker excels his product.” What does me he mean by this?

First, the agent is the thing acting, and the patient the thing acted upon. If I carve a figure out of wood, I am the agent, and the wood is the patient.

Second, the agent brings about a change in the patient. Every change is a move from some potency to some act through some form. If I carve a piece of wood into the shape of a dog, say, then I have a taken a piece of wood, a thing that has the potential to take on the shape of a dog, and given that shape, that form, to the piece of wood. In other words, the agent gives a new form to the patient.

Now, no agent can give what it does not have. In order to bring about the change, I must be capable of so doing. I must know what a dog looks in order to carve a wooden dog. Thus, with respect to any particular change, the thing changed cannot be greater than the agent which is changing it.

In short, a physical mechanism cannot give a human fetus an immaterial soul; it does not have that form to give.

Moreover, a thing that has new existence must also have a new becoming; for that which is, must first become, since a thing becomes in order that it may be. Thus things which have being in their own right must have becoming in their own right; such are subsistent beings. But things that do not possess being in their own right do not properly have a becoming; such are accidents and material forms.

A person “becomes”, comes to be, when the egg is fertilized. Prior to that moment there was no person; after it there is. For that person to be, it must have come to be.

The rational soul has being in its own right, because it has its own operation, as is clear from our previous discussion.

Therefore, the rational soul is a substance, and must come to be. I’m not sure why having its own operation requires that the rational soul is a being in its own right. (One more connection I’ve not yet made.)

Now here’s the fascinating bit:

Therefore becoming is properly predicated of the rational soul. Since the soul is not composed of matter and form, as was shown above, it cannot be brought into being except by creation. But God alone can create, as we said above. Consequently the rational soul is produced by God alone.

A material being can come to be when a substantial form is given to matter. But an immaterial being cannot come into being in this way. It has to be created ex nihilo, from nothing. Only God can do that.

This had never occurred to me. It makes all kinds of sense, though. Through God’s providence, the world has a built-in mechanism for all kinds of things to come to be that doesn’t involve God’s active creation from nothing. But the human soul is different. That’s very cool.

We can readily understand why this should be so. In all arts that are hierarchically related to one another, we observe that the highest art induces the ultimate form, whereas the lower arts dispose matter for the reception of the ultimate form. The rational soul, evidently, is the ultimate and most perfect form that the matter of beings subject to generation and corruption can achieve. Therefore natural agents, which operate on lower levels, appropriately cause preliminary dispositions and forms, whereas the supreme agent, God, causes the ultimate form, which is the rational soul.

If the agent must be greater than the patient, then the greater the form to be imparted, the greater the agent must be. For the supreme form in the material world, the human soul, only God’s power will suffice.

To set aside such quibbles, we should reflect that, in material things, one species surpasses another in perfection, in the way that, in numbers, species are diversified by adding one to another. Whatever perfection is found in lifeless bodies, plants also possess, and more besides. Again, whatever plants have, animals have too, and something else in addition. And thus we proceed until we come to man, the most perfect of bodily creatures. All that is imperfect is related as matter to what is more perfect. This is clear in the various classes of beings.

A plant is body that has life. It’s not like you can divide a plant into two pieces, one that’s the body and one that’s the life, like dividing a car into an engine and everything else. As you move down through the genera, each kind of body gets richer and richer, not composed of more and more parts.

The elements constitute the matter of bodies that are composed of similar parts; and again, bodies having similar parts are matter with respect to animals. And this is likewise to be observed in one and the same being. Among natural things, that which is endowed with a higher degree of perfection has, in virtue of its form, whatever perfection is found in lower nature, and in virtue of the same form has, besides, its own added perfection.

I think this is what I just said, though not so nicely.

Through its soul, the plant is a substance, and is corporeal, and besides is an animated body. Through its soul, an animal has all these perfections, and moreover is sentient. In addition to all this, man is intelligent through his soul. Thus, in any object, if we consider what pertains to the perfection of a lower grade of being, this will be material when compared with what pertains to the perfection of a higher grade. For example, if we observe that an animal has the life of a plant, this life is in some fashion material with respect to what pertains to sensitive life, which is characteristic of an animal.

“Material” and “formal” are two words that I boggle at once in a while. I understand what they mean in certain contexts, and then Thomas goes and uses them in some way that I don’t get. I assume that they have a wider meaning than I really get. Let’s see if I can tease it out.

A species, such as “animal”, is, of course, a form—or, at least, includes one in its definition. And “animal” represents something added to “plant”, as a form is added to matter and makes it something new, or gives it a new quality.

Genus, of course, is not matter, for then it would not be predicated of the whole. But it is something derived from matter; for the designation attaching to a thing in terms of what is material in it, is its genus.

I remember this from De Ente et Essentia (or perhaps it was Porphyry) but it made more sense then.

Specific difference is derived from the form of a thing in the same way. This is the reason why living or animated body is the genus of animal, and sensitive is the specific difference that constitutes it. Similarly, animal is the genus of man, and rational is the difference that constitutes him. Therefore, since the form of a higher grade of being comprises within itself all the perfections of a lower grade, there is not, in reality, one form from which genus is derived, and another from which specific difference is derived. Rather, genus is derived from a form so far as it has a perfection of lower degree, and specific difference is derived from the same form so far as it has a perfection of higher degree.

OK, now, this makes sense. No genus gives a thing form; no specific difference gives a thing form; only a species with actual individuals gives anything form.

Thus, although animal is the genus of man and rational is the specific difference constituting him, there need not be in man a sensitive soul distinct from the intellectual soul, as was urged in the first argument.

The first argument argued that an animal, having a sensitive soul, was in potency with respect to a rational soul, that is, that a rational soul is something that could be added. But “rational” is a specific difference, not a form; it can’t be added like that.

This indicates the solution of the second difficulty.

Which was that the intellect has no bodily organ whereas the sense does; thus, the intellect is separated from the body and the sense is not, and one thing can’t be both separated and unseparated.

As we have pointed out, the form of a higher species comprises within itself all the perfections of lower classes of being. We must note, however, that the species of a material being is higher in proportion as it is less subject to matter. And so the nobler a form is, the more it must be elevated above matter.

Hence the human soul, which is the noblest of all forms of matter, attains to the highest level of elevation, where it enjoys an activity that is independent of the concurrence of corporeal matter. Yet, since the same soul includes the perfection of lower levels, it also has activities in which corporeal matter shares. However, an activity is exercised by a thing in accordance with the thing’s power. Therefore the human soul must have some powers or potentialities that are principles of activities exercised through the body, and these must be actions of certain parts of the body. Such are the powers of the vegetative and sensitive parts. The soul has also certain powers that are the principles of activities exercised without the body. Such are the powers of the intellectual part, whose actions are not performed by any organs. For this reason both the possible intellect and the agent intellect are said to be separate; they have no organs as principles of their actions, such as sight and hearing have, but inhere in the soul alone, which is the form of the body. Hence we need not conclude, from the fact that the intellect is said to be separate and lacks a bodily organ, whereas neither of these is true of the senses, that the intellectual soul is distinct from the sensitive soul in man.

The intellect is separate from the body, but the soul as a whole is not. In animals, you might say that the soul is coextensive with the body, and contains in; in humans, it’s as though the soul extends a little bit beyond the body.

This also makes it clear that we are not forced to admit an intellectual soul distinct from the sensitive soul in man on the ground that the sensitive soul is corruptible whereas the intellectual soul is incorruptible, as the third objection set out to prove. Incorruptibility pertains to the intellectual part so far as it is separate. Therefore, as powers that are separate, in the sense mentioned above, and powers that are not separate, are all rooted in the same essence of the soul, there is nothing to prevent some of the powers of the soul from lapsing when the body perishes, while others remain incorruptible.

You can’t sense without senses…but it isn’t that the soul of a dead person lacks the power of sense, it just lacks the ability to make use of it. This is what makes the doctrine of the Resurrection of the Body so exciting; we’ll have new bodies, better than before, and all of our faculties will work better than ever.

The points already made lead to a solution of the fourth objection.

Which was that a human fetus is first a living body but not sentient, and then sentient but not rational, and then rational, and so these faculties are added as accidents to a base substance.

All natural movement gradually advances from imperfect to perfect. The same quality is receptive of greater and less; hence alteration, which is movement in quality, being unified and continuous in its progress from potency to act, advances from imperfect to perfect. But substantial form is not receptive of greater and less, for the substantial nature of each being exists indivisibly. Therefore natural generation does not proceed continuously through many intermediate stages from imperfect to perfect, but at each level of perfection a new generation and corruption must take place. Thus in the generation of a man the fetus first lives the life of a plant through the vecetative soul; next, when this form is removed by corruption it acquires, by a sort of new generation, a sensitive soul and lives the life of an animal; finally, when this soul is in turn removed by corruption, the ultimate and complete form is introduced. This is the rational soul, which comprises within itself whatever perfection was found in the previous forms.

With all due respect, I think Thomas must be wrong, here. He would have a human develop in stages, losing one soul then gaining another twice in the womb. It seems to me more likely that a human embryo gains a rational soul immediately, and then grows into it. The intellect requires sense phantasms to work upon, and it can’t get them until the body’s senses develop; but just as the soul of a dead man cannot exercise its sense, so the soul of an embryo cannot.

Thomas begins,

Certain considerations seem opposed to our doctrine. In the first place, specific difference is to genus what form is to matter. Animal is the genus of man, and rational is the difference that makes man what he is. Accordingly, since animal is a body animated by a sensitive soul, it seems that a body animated by a sensitive soul is still in potency with respect to the rational soul. Thus the rational soul would be distinct from the sensitive soul.

Hmmm.  Form makes matter what it is; matter that does not possess a particular form (but can) is in potency with respect to that form. My son can dye his hair blue, but he has not yet done this; his hair is blue in potency.  Just as blueness can be added to my son’s hair to make it blue in act, the specific difference “rational” can be added to the genus “animal” to make it “man” in act.  Thus, “animal” is in potency with respect to “rational”…and rationality is an accident added to an animal substance.  Hence, the rational soul must be distinct.  The error, I think, is that the objector is using an invalid analogy.  We’ll see.

Moreover, the intellect does not possess a bodily organ. But the sensitive and nutritive powers do possess bodily organs. Hence it seems impossible for the same soul to be both intellectual and sensitive, because the same thing cannot both be separated and not separated from another thing.

That’s clear enough.  But must two things which are “not separated” be coextensive?  I don’t see why they should be.

Furthermore, the rational soul is incorruptible, as was shown above. On the other hand, the vegetative and the sensitive souls are corruptible, as they are acts of corruptible organs. Therefore the rational soul is not the same as the vegetative and the sensitive souls, for the same thing cannot be both corruptible and incorruptible.

The problem here, I think, is the lack of a distinction between souls on the one hand and faculties on the other.  The vegetative soul has the vegetative faculty: plants can take in nutrition and grow.  The sensitive soul has the vegetative faculty and the sensitive faculty.  The rational soul has the vegetative, sensitive, and rational faculties.

Thus, it’s not that man has a vegetative soul, a sensitive soul, and a rational soul; rather, he possesses all three faculties in one rational soul.  The first two faculties require corruptible organs, that is, material organs that can die; the last does not.

Besides, in the generation of man the life conferred by the vegetative soul appears before the fetus is observed to be an animal from its sense activity and motion; and this same being is discerned to be an animal through its sense activity and movement before it has an intellect. Therefore, if the soul by which the fetus first lives the life of a plant, then the life of an animal, and thirdly the life of a man, is the same, it would follow that the vegetative, sensitive, and rational principles come from an outside source, or else that the intellectual soul arises from the energy in the semen. Both of these alternatives are inadmissible. On the one hand, since the operations of the vegetative and sensitive soul are not exercised apart from the body, their principles cannot be without a body. On the other hand, the operation of the intellectual soul is exercised without a body; and so, apparently, no bodily energy can be its cause. Therefore the same soul cannot be vegetative, sensitive, and rational.

One can argue with St. Thomas’ notion of fetal development, but I’ll slide past that.  The argument here appears to be that since the vegetative and sensitive souls require bodily organs, they are caused by the body; and yet, being immaterial, the rational soul, or intellect, cannot be caused by the body; and since they have two distinct causes, they must be two distinct things.  But the body is not the principle of the soul; the soul is the principle—the form—of the body. 

I suppose you could think of this chapter as a sort of quiz, with essay questions.  We’ll see how I did when I blog the next chapter.

That there cannot be several souls in one body is proved as follows. The soul is evidently the substantial form of any being possessing a soul, because a living being is constituted in genus and species by its soul. But the same thing cannot have several substantial forms. A substantial form differs from an accidental form in this, that a substantial form causes a particular thing simply to be, whereas an accidental form is added to a particular being already constituted as such, and determines its quality or quantity or its mode of being. Hence, if several substantial forms belong to one and the same thing, either the first of them causes it to be this particular thing or it does not. If it does not, the form is not substantial; if it does, then all the subsequent forms accrue to what is already this particular thing. Therefore none of the subsequent forms will be the substantial form, but only some accidental form.

Clearly, therefore, one and the same thing cannot have several substantial forms; and so one and the same person cannot have several souls.

I am a human being, a rational animal, because I have a human soul. If I didn’t have a human soul, I’d be something else. My soul is my substantial form, that which makes me a substance; and I can have only one of those, so I can have only one soul.

However, there’s clearly more going on in the sentence I bolded than meets the eye.

Furthermore, it is evident that a man is said to be living because he bas a vegetative soul, that he is called an animal because he has a sensitive soul, and that he is a man because he has an intellectual soul. Consequently, if there were three souls in man, namely, vegetative, sensitive, and rational, man would be placed in a genus because of one of his souls, and in a species because of another. But this is impossible. For thus genus and specific difference would constitute, not what is simply one, but what is one per accidens, or a sort of conglomeration, such as musical and white; but such is not a being that is simply one. Accordingly a man can have only one soul.

A species defines one kind of thing; it is the essence of the things that it is the species of. It is, in fact, the form the individual members of the species. As such, it needs to be one, not three.

Someday maybe I’ll have a deep understanding of genus, species, and so forth. I know enough to understand what Thomas is saying, but not enough to see all of the implications.

Aristotle and Thomas would doubtless say not; and John C. Wright explains why.

Not only the agent intellect and the possible intellect, but also all the other powers that are principles of the soul’s operations, are united in the essence of the soul. All such powers are somehow rooted in the soul. Some of them, indeed, such as the powers of the vegetative and sensitive parts, are in the soul as in their principle, but in the composite as in their subject, because their activities pertain to the composite, not to the soul alone; for power and action belong to the same subject. Some of them, on the other hand, are in the soul both as principle and as subject, for their operations pertain to the soul apart from any bodily organ. These are the powers of the intellectual part. But a man cannot have several souls. Accordingly all the powers must pertain to the same soul.

Remember that plants and animals have souls as well, that is, they are alive, they have “breath”, which is what the Greek word for “soul” means. A plant’s faculties of growth and ingestion are rooted in the plant’s life, in its soul. An animal adds the faculties of movement and sense. But these faculties, though rooted in the plant’s or animal’s soul, involve the body as well. It is the body that grows, and the body that senses. Man has a rational soul: he has the faculties of the plants and animals, but adds intellect, which is not only rooted in the soul but is wholly contained with it.

But a man cannot have several souls, so all of these powers must be rooted in one and the same soul, the only one he’s got. Why? That’s the next chapter.

This leads me to a couple of questions.

First, I understand that accidents subsist in a substance.  Now, suppose you’ve got a thing whose nature it is to be infinite.  It’s part of the thing’s essence, its species.  Is this infinity still an accident?

Second, God is One, and perfectly simple; if I understand it correctly, God has no accidents.  Yet God is said to be infinite.  I would gather, then, that this is an analogical use of the word "infinite".  The infinite of quantity and the infinite of God are distinct, but related analogically.  Not so?

We have still to consider how this union is possible. Some difficulty may seem to arise in this matter. The possible intellect is in potency with respect to all that is intelligible, whereas the agent intellect causes what is intelligible in potency to be intelligible in act, and so must be related to what is intelligible as act to potency. But the same thing, seemingly, cannot be both in potency and in act with respect to the same object. Thus it would appear that the possible intellect and the agent intellect cannot be united in the same substance of the soul.

How can one thing, one human soul, be both in potency and act with respect to a single object?

I confess, this is not a matter of great concern to me, but I resolved when I began to work all of the way through the Compendium Theologiae, without skipping anything, so I’ve got to go through it. That’s no reason that you have to. In this particular case, I’m just going to let Thomas speak for himself, and highlight a couple of interesting points in the discussion.

This doubt is easily resolved if we examine how the possible intellect is in potency with respect to intelligible objects, and how the agent intellect renders them actually intelligible. The possible intellect is in potency with regard to intelligible objects in the sense that it does not contain within its nature any determinate form of sensible things. In the same way the pupil of the eye is in potency with regard to all colors. To the extent, then, that phantasms abstracted from sensible things are likenesses of definite sensible things, they are related to the possible intellect as act to potency. Nevertheless the phantasms are in potency with regard to something that the intellectual soul possesses in act, namely, being as abstracted from material conditions. And in this respect the intellectual soul is related to the phantasms as act to potency. No contradiction is involved if a thing is in act and potency with regard to the same object according to different points of view. Thus natural bodies act upon each other and are acted upon by each other, for each is in potency with respect to the other. The same intellectual soul, therefore, can be in potency with regard to all intelligible objects and nevertheless, without any contradiction, can be related to them as act, if both a possible intellect and an agent intellect are acknowledged in the soul.

There’s more than one way to look at most things, and intelligible objects are surely one of them. You can be in potency with respect to it in one way, and in act with respect to it in another. How can I have my cake in potency and act at the same time? I can have it before me in act, and have it in my stomach in potency. Once I have eaten it, I have in my stomach in act, and (if it was a large cake, and I ate it all) I can have it before me in potency.

This will be seen more clearly from the way the intellect renders objects actually intelligible. The agent intellect does not render objects actually intelligible in the sense that the latter flow from it into the possible intellect. If this were the case, we would have no need of phantasms and sense in order to understand. No, the agent intellect renders things actually intelligible by abstracting them from phantasms; just as light, in a certain sense, renders colors actual, not as though it contained the colors within itself, but so far as it confers visibility on them. In the same way we are to judge that there is a single intellectual soul that lacks the natures of sensible things but can receive them in an intelligible manner, and that renders phantasms actually intelligible by abstracting intelligible species from them. The power whereby the soul is able to receive intelligible species is called the possible intellect, and the power whereby it abstracts intelligible species from phantasms is called the agent intellect. The latter is a sort of intelligible light communicated to the intellectual soul, in imitation of what takes place among the higher intellectual substances.

As usual, Thomas puts things better than I do. I like this description of the possible and agent intellect, and I especially like the description of the agent intellect as a “sort of intelligible light communicated to the intellectual soul…” We often say that a clear explanation casts light on a dim subject. The divine light of reason shines upon us and casts light on the objects we sense, allowing us to abstract universal concepts from them. It is by the divine light of reason that I can see that animal, and know that it is an animal, and not just any animal, but a dog.

Why is this in imitation of the angels, the “higher intellectual substances”? Because, according to Thomas, God in a sense pre-equips them with the intelligible species that they need. They have no senses; they do not perceive. Rather, their intellects apprehend directly. They do not abstract universals from sensible objects, but just know them.

What a peculiar creature Man is, to be sure.

But the point he makes, or rather makes use of, is this.  Every science has certain principles on which it is founded.  By its nature it takes these principles as given.  For example, geometry assumes certain definitions and axioms; physics presumes multiple beings in motion.

A science is responsible only for those conclusions that can be drawn from its principles.  Indeed, it is only competent to judge propositions that purport to be drawn from its principles.  Other propositions are outside of its field of view, and it cannot address them.

Among these propositions is the one that says, "This principle, upon which you base your science, is wrong."  No science is competent to pass judgment on the principles upon which it is based.  This is not to say that this is a question of no importance to the practitioners of the science in question; clearly, it’s crucial.  But it cannot be addressed in terms of the science itself.  It must be addressed on some higher, prior basis.

And this is why, of course, that experimental science as it is practiced today is not competent to address questions such as the existence of God, or the nature of human consciousness, neither of which are explainable in terms of controlled experiments involving the movement of atoms. 

As a blog post I read recently pointed out, modern experimental psychology and neuro-biology takes great pains to eliminate the effects of rational human choice from its experiments.  Such experiments are testing Man not as Rational, but as Animal, and naturally they miss the mark here too.

…it is not reasonable to begin one’s study with commentaries; we should first read the text and then turn to the commentators when our own powers of comprehension fail.  This will not take long.

Nor did it.  I’ve been wrestling with Prof. Coughlin’s translation on and off for some months, and gotten some notions, but I’ve not gotten far.  Prof. Coughlin goes on to say that the best commentary on the Physics is that of St. Thomas Aquinas, and particularly recommends this edition, published by Dumb Ox Books.  I’ve since received this, and I’m liking it a lot.

The book includes the complete text of the Physics, in comfortably sized sections interleaved with Thomas’ commentary.  Thomas doesn’t settle for merely explicating the text; he puts the passage in context, and also gives considerable background that Aristotle assumes.  And since Aristotle’s own words are separate, it’s possible to give them a good study before moving on to what Thomas has to say about them.  Good stuff.

I don’t intend to blog my way through Aristotle the way I’m doing through the Compendium Theologiae, though I’ll undoubtedly have a few reflections to make as I go along.

Since the agent intellect and the possible intellect are united to us as form, we must acknowledge that they pertain to the same essence of the soul.

I do not understand what he means by “the same essence of the soul.” The essence of something is what it is. The essence of a dog is to be a dog. The essence of a man is to be a rational animal. Does a man’s soul have its own essence apart from the essence of a man? But let’s move on. Thomas then says,

Whatever is formally united to another thing, is united to it either in the manner of a substantial form or in the manner of an accidental form. If the possible intellect and the agent intellect were united to man after the fashion of a substantial form, we would have to hold that they share in the one essence of that form which is the soul, since one thing cannot have more than one substantial form.

Right. If a man’s intellect is part of his substantial form, then it part of his soul, for his soul is his substantial form.

On the other hand, if they are united to man after the fashion of an accidental form, neither of them, evidently, can be an accident of the body. Besides, the fact that their operations are performed without a bodily organ, as we proved above, shows that each of them is an accident of the soul. But there is only one soul in one man. Therefore the agent intellect and the possible intellect must inhere in the one essence of the soul.

In other words, the agent and possible intellect are united with the soul either substantially or accidentally, not with the body as such.

Furthermore, every action that is proper to a species proceeds from principles that emanate from the form which confers the species. But the action of understanding is an operation proper to the human species. Therefore the agent intellect and the possible intellect, which are principles of this action, as has been shown, emanate from the human soul, whence man has his species. However, they do not issue from the soul in such a way as to extend to the body, because, as we have said, the operation in question takes place independently of a bodily organ. Since, therefore, action pertains to the same subject as does potency, the possible intellect and the agent intellect inhere in the one essence of the soul.

I am rational because I am a man, a rational animal. It is part of being human, part of the very definition of being human, to be rational. It is my intellect that makes me rational: I must necessarily have one. But the intellect is immaterial; so it must “inhere in the one essence of the soul.”

There’s clearly a distinction I’m missing here; I don’t understand why Thomas insists on “inhere in the one essence of the soul” rather than just “inhere in the soul”.

There were also some philosophers who argued that, even granting the diversification of the possible intellect in men, at any rate the agent intellect was but one for all. This view, while less objectionable than the theory discussed in the preceding chapter, can be refuted by similar considerations.

So what’s the difference between the possible intellect and the agent intellect? As I understand it—and I’m not at all sure that I really do understand it—the possible intellect is like the memory of the intellect. As I learn about more and more things, the intelligible species by which I understand them get squirreled away in the possible intellect. It’s called the possible intellect, because it’s the collection of concepts that it’s possible for me to bring to mind. I understand this vast collection of intelligible species in potency, but not in actuality.

The agent intellect is so called because it is the agent—the efficient cause—of my understanding something. It does two things: first, when I bring a concept to mind, the agent intellect brings it from potency to act in my mind; and second, when I learn to understand a new thing it is the agent intellect that abstracts the essence of the thing, its species, from it and makes it intelligible.

Or, as Thomas says,

The action of the possible intellect consists in receiving the objects understood and in understanding them. And the action of the agent intellect consists in causing things to be actually understood by abstracting species. But both these functions pertain to one particular man. This man, for example, Socrates or Plato, receives the objects understood, abstracts the species, and understands what is abstracted. Hence the possible intellect as well as the agent intellect must be united to this man as a form. And so both must be numerically multiplied in accord with the number of men concerned.

In short, without going into a detailed argument as he did in Chapter 85, Thomas simply points out that when I understand something it’s I who understand it, and when you understand something it’s you who understand it, and to say that we might be sharing a single intellect to do the job is just silly.

Nevertheless, Thomas does go on to say why it makes sense:

Moreover, agent and patient must be proportionate to each other. Examples are matter and form, for matter is reduced to act by an agent.

The agent is the efficient cause, the thing making a change occur, and the “patient,” I take it, is the thing acted upon. The agent intellect acts upon the possible intellect, and hence they must be proportionate to each other. I believe that he means “proportionate” in the same way that we’d might say that an object is disproportionate to a container that’s too small for it. They have to fit together.

This is why an active potency of the same genus corresponds to every passive potency; for act and potency pertain to one genus. But the agent intellect is to the possible intellect what active potency is to passive potency, as is clear from this discussion. Hence they must both pertain to one genus. Therefore, since the possible intellect has no separate existence apart from us, but is united to us as a form and is multiplied according to the number of men, as we have shown, the agent intellect must likewise be something that is united to us as a form, and must be multiplied according to the number of men.

OK, now here are a couple of terms I’ve not run into before: “active potency” and “passive potency”. I’ll guess that a thing has an active potency if it’s capable of doing something but isn’t currently doing it, and that a thing has passive potency if something can be done to it but it isn’t currently being done. Thus, I can pick up that ball and throw it, and that ball can be picked up and thrown, and gosh, wow, sure enough, the active potency and the passive potency are proportionate to each other. They fit. I suppose one could say that they pertain to one genus.

So anyway, the same is true of the agent intellect and the possible intellect. The agent intellect is capable of bringing a concept to mind, and the possible intellect can provide one. And so they must both pertain to one genus, which means (I’m not entirely sure why; I think Thomas might be skipping a few steps) that they must both be united to a man as a form.

So we’ve each got a possible intellect and an agent intellect of our very own.

The arguments advanced to support the contrary view are easily answered.

The first objection is that if each man has his own intellect, then each man has his own set of concepts by which he understands the things he perceives; and consequently these concepts are not, in fact, universals. But universals are precisely what we understand, and so consequently each man cannot have his own intellect.

The first argument has many defects. First of all, we concede that the same thing may be understood by all. By the thing understood I mean that which is the object of the intellect. However, the object of the intellect is not the intelligible species, but the quiddity of the thing. The intellectual sciences are all concerned with the natures of things, not with intelligible species; just as the object of sight is color, not the species of color in the eye. Hence, although there may be many intellects belonging to different men, the thing understood by all may be but one; just as a colored object which many look at is but one.

I see a dog. The concept, or intelligible species, “dog” appears in my mind. But I do not understand this concept, “dog”; rather, I understand that this dog standing before me is a dog. Concepts are like pointers in a computer language: the thing of interest is not the pointer itself, but the data at which it points. Thus, when you and I see a dog, we each have our own concept; but those concepts both point at the same thing, viz, Dogginess, what it is to be a dog.

This next bit speaks to a passage I didn’t understand in the first objection; if you go back to Part II, you’ll find it:

Secondly, the consequence does not necessarily follow that, if a thing is individual, it is understood in potency and not in act. This is true only of things that are individuated by matter. Of course, what is understood in act must be immaterial. Accordingly immaterial substances, even though they may be individuals existing by themselves, are understood in act. The same holds for intelligible species, which are immaterial; although they differ numerically in me and in you, they do not on that account lose their property of being intelligible in act. The intellect that understands its objects by means of them reflects upon itself, thereby understanding its very action of understanding as well as the species whereby it understands. Moreover, we should realize that, even if we admit but one intellect for all men, the difficulty is still the same. There would still remain many intellects, because there are many separate substances endowed with intelligence. And so it would follow, pursuing our adversaries’ line of reasoning, that the objects understood would be numerically different, hence individual and not understood in first act. Obviously, therefore, if the objection under discussion had any cogency, it would do away with a plurality of intellects simply as such, and not merely in men. Since this conclusion is false, the argument manifestly does not conclude with necessity.

Since I didn’t understand this part of the objection, I don’t really understand the answer. But it’s interesting to note that the objection is really an argument that there’s only one Intellect, period, not that there’s only one Intellect for all men. If the objection were cogent, then all men, angels, and God would share a single intellect.

The second objection is that each intellectual substance must belong to a separate species. Thus, if you and I have distinct intellects, we must belong to different species. But this is an unfair extrapolation from the case of angels.

The second argument is readily answered, if we but consider the difference between an intellectual soul and separate substances. In virtue of its specific nature, the intellectual soul is meant to be united to some body as the latter’s form; the body even enters into the definition of the soul. For this reason, souls are numerically differentiated according to the relation they have to different bodies; which is not the case with separate substances.

By “separated substances”, Thomas means angels, immaterial spirits. But there’s a difference between the human soul and an angel, even though both are immaterial and intellectual: it is part of the human soul’s nature to have a body, and it is the relation of the soul to the body that makes human souls distinct. In short, people aren’t angels.

The third objection is that if souls are made distinct by the possession of a body, then when the body dies nothing remains to distinguish between two souls. Consequently, there can be only one soul among all men.

This also indicates how the third argument is to be answered. In virtue of its specific nature, the intellectual soul does not possess the body as a part of itself, but has only an aptitude for union with the body. Therefore it is numerically differentiated by its capacity for union with different bodies. And this remains the case with souls even after their bodies have been destroyed: they retain a capacity for union with different bodies even when they are not actually united to their respective bodies.

That is, my body is not part of my soul; but my soul has a particular aptitude to be united with my particular body. It’s as though the soul and body interlock like a plug in a socket; each person’s socket is different. Even when the body dies and the plug is removed from the socket, my soul’s plug is different than yours.

And that wraps up our discussion of the (lack of) unity of the possible intellect. Next, we get to look at the agent intellect.

I’ve just re-read them myself, in preparation to continue, and I think they hold up OK. There’s one point I’d like to clarify. In Part I, I say

And then you’ve got humans, who are individuated by matter, as animals are, but have an intellectual (and hence immaterial) soul, as angels do.

This is not quite right: an angel does not have an intellectual and immaterial soul; rather, an angel is an intellectual and immaterial spirit. The human soul is also intellectual and immaterial spirit.

But this is a nit.

In Part II, Thomas speaks of those who would say that all men share a single Soul. Having described that position, he now goes on to explain how every man can have a unique soul while remaining members of the one species.

The absurdity of this whole position is easily perceived.

Ahem.

To make this clear, let us proceed as one would proceed against those who deny fundamental principles. That is, let us establish a truth that simply cannot be denied. Let us suppose that this man, for example, Socrates or Plato, understands. Our adversary could not deny that the man understands, unless he knew that it ought to be denied. By denying he affirms, for affirmation and denial are intelligent actions.

Thomas is, I gather, trying to prove that man can understand to one who denies it. He posits that Socrates can understand. The denier cannot rationally deny that Socrates understands unless the denier has a good reason. But if denier has a good reason, that reason is an act of understanding! Therefore, the denier must either affirm that Socrates understands or, in denying it, affirm that he himself understands. Thus, it is possible for a man to understand.

(Remember that for Thomas, to understand is to know intellectually. If I see a dog, the appearance of the dog is present to my Sense: I perceive the dog, I have a perception. When I recognize that I perceive a dog, the concept dog is now present to my intellect, and I understand that this object before me is a dog.)

If, then, the man in question understands, that whereby he formally understands must be his form, since nothing acts unless it is in act.

There is act, that which is, and potency, that which could be. I am here; I could be there. I am hungry; I could be full. I am thinking; I could be asleep. Anything that I actually am, or actually do, involves bringing something potential into actuality. That’s the first thing. And the second thing is, actuality always involves form.

When I understand something in actuality, rather than just potentially, I am acting; and that by which I understand, as a formal cause of my understanding, is my form.

Hence that whereby an agent acts, is his act; just as the heat by which a heated body causes warmth, is its act. Therefore the intellect whereby a man understands is the form of this man, and the same is true of another man.

My intellect is my form; and your intellect is your form.

But the same numerical form cannot belong to numerically different individuals, for numerically different individuals do not possess the same existence; and yet everything has existence by reason of its form. Accordingly the intellect whereby a man understands cannot be but one in all men.

What makes me me is mine; and what makes you you is yours. These are two separate, numerically distinct things. What makes me me is my form, and as shown above my form is my intellect. The same applies to you. Thus, my intellect and your intellect are distinct.

Perceiving the force of this difficulty, some endeavor to find a way of escaping it. They say that the possible intellect, of which there was question above, receives the intelligible species by which it is reduced to act. These intelligible species are, in some way, in the phantasms. Hence the possible intellect is continuous and is joined to us so far as the intelligible species is both in the possible intellect and in the phantasms that are in us. It is thus that we are able to understand through the agency of the possible intellect.

Now things get a little difficult. (Now? Now, he says?) We need to review some background.

Every man has Intellect and Sense. Sense is the faculty with which we sense the outside world through our sight, smell, taste, touch, and hearing; it’s also the faculty whereby we imagine things of this sort. When I see my son, there is an image in my Sense. When I picture the face of my son, I am using my imagination: I am bringing forth an image from my memory. Again, the image is in my Sense. This kind of image, however derived, and whichever senses are involved, is what Thomas means by a “phantasm”.

Now, the Sense belongs to our animal nature: every animal has it to a greater or lesser degree. It is, consequently, an aspect of our material bodies, and in particular of our brains.

Our Intellect, as we’ve said before, is immaterial: non-human animals have no intellect, and cannot be said to be rational.

Now, there is a link between the Sense and the Intellect. We see the world, resulting in phantasms in our Sense. Our Intellect apprehends the natures of these phantasms, resulting in intelligible species in our possible intellect.

At this point, you should probably go back and re-read the last quoted passage.

There are those who insist that Intellect is one, that all humans share one Intellect. But our Intellect is our form, that which gives us existence; we must each have our own. Those who insist that the intellect is one try to get around this by pointing out the link between the Intellect and the Sense. The intelligible species understood by the Intellect are somehow present in the phantasms perceived by the Sense. This roots the shared Intellect in the individual man’s Sense, and makes it appear individuated without its really being so.

So they say, but Thomas strongly disagrees:

Unfortunately for this solution, it is utterly valueless.

This is a remarkably strong statement for Thomas; he’s usually more understated.

In the first place, the intelligible species, as it exists in the phantasms, is a concept only in potency; and as it exists in the possible intellect, it is a concept in act. As existing in the possible intellect, it is not in the phantasms, but rather is abstracted from the phantasms. Hence no union of the possible intellect with us remains.

We understand intelligible species, or (as we would say today) concepts. The concepts are present in the phantasms in potency only, not in act; the Intellect brings them into act by abstracting them from the phantasms. If the Intellect is one and shared by all men, then “no union of the possible intellect with us remains.”

Secondly, even granting that there may be some sort of union, this would not suffice to enable us to understand. The presence of the species of some object in the intellect does not entail the consequence that the object understands itself, but only that it is understood; a stone does not understand, even though a species of it may be in the possible intellect. Hence, from the fact that species of phantasms present in us are in the possible intellect, it does not follow that we thereupon understand. It only follows that we ourselves, or rather the phantasms in us, are understood.

If I perceive a stone, a phantasm of that stone appears in my Sense. And if there is a sufficient union of my Sense with this “shared intellect”, as Thomas denies, that the concept Stone appears in the shared intellect, this means that the Stone is understood by the shared intellect; it does not mean that I, an individual, am the one who understands Stone.

This will appear more clearly if we examine the comparison proposed by Aristotle in Book III of De anima [7, 431 a 14], where he says that the intellect is to phantasm what sight is to color. Manifestly, the fact that the species of colors on a wall are in our vision does not cause the wall to see, but to be seen. Likewise, the fact that the species of the phantasms in us come to be in the intellect, does not cause us to understand, but to be understood.

If the intellect that understands my phantasms is not mine, then I am understood, but I cannot say that I understand.

Further, if we understand formally through the intellect, the intellectual action of the intellect must be the intellectual action of the man, just as the heating action of fire and of heat are the same. Therefore, if intellect is numerically the same in me and in you, it follows that, with respect to the same intelligible object, my action of understanding must be the same as yours, provided, of course, both of us understand the same thing at the same time. But this is impossible, for different agents cannot perform one and the same numerical operation. Therefore it is impossible for all men to have but a single intellect.

My understanding is my understanding, and your understanding is yours. We can both understand the same thing, but not by the same act.

Consequently, if the intellect is incorruptible, as has been demonstrated many intellects, corresponding to the number of men, will survive the destruction of their bodies.

Thus, every man must have his own Intellect. And since the Intellect is incorruptible, then when men die their Intellects remain.

I think I understood some of that, but certainly not all of it.

In the next part, we’ll look at Thomas’ answer to the objections listed in Part II.

An objector may say: the intellect is indeed incorruptible, but there is only one intellect in all men; and so what remains after the corruption of all men is but one. That there is only one intellect for all men, the objector may continue, can be established on many grounds.

So much we said yesterday.

First, on the part of the intelligible species. If I have one intellect and you have another, there will have to be one intelligible species in me and another in you, and consequently there will be one object that I understand and another that you understand. Hence the intelligible species will be multiplied according to the number of individuals, and so it will not be universal but individual. The conclusion would then seem to follow that it is understood not in act, but only in potency; for individual species are intelligible in potency, not in act.

When I apprehend an object, what I have in my possible intellect is its intelligible species. And indeed, this intelligible species will be multiplied by the number of individuals. So how can the intelligible species be a universal? (The answer, as we will see, is that it isn’t, and that’s OK.) The meaning of the italicized sentence eludes me tonight.

Moreover, since the intellect, as we have seen, is a substance subsisting in its own being, and since intellectual substances that are numerically many do not belong to one species, as we have also seen, it follows that if I have one intellect and you have another that is numerically different, the two must differ specifically. And so you and I would not belong to the same species.

I talked about this yesterday. To be numerically many, the object says, two beings must either be of different species, as angels are, or of the same species and distinguished by having different matter, as animals are. Thomas is going to choose a third option.

Furthermore, since all individuals share in one specific nature, there must be something besides specific nature whereby individuals may be distinguished from one another. Accordingly, if there is one specific intellect in all men, but many intellects that are numerically distinct, something must be found that will make one intellect differ numerically from another. This cannot be anything pertaining to the substance of the intellect, since the intellect is not composed of matter and form. Consequently any difference that might be admitted, on the part of the substance of the intellect, would be a formal difference that would cause diversity in the species. The only possibility left is that the intellect of one man cannot differ numerically from the intellect of another man except by reason of the diversity of their bodies. Therefore, when the various bodies corrupt, it seems that only one intellect, and not a plurality of intellects, would remain.

Something distinguishes one man from another, and it appears to be the possession of a body. For my intellect to be distinct from yours, while being immaterial, would seem to make us be of two different species, which is not the case. Thus, when I die and you die, there’s nothing to distinguish the intellect that remains. I take it that this is another way of saying the previous point.

The absurdity of this whole position is easily perceived….

But that’s another post.

Here’s some background. Animals have a nature, an essence, a species, that serves them as their substantial form. It is a purely material form: it gives form to their matter, and has no immaterial aspect. And, within that species, all individuals have the same species, the same substantial form. There is one species, Dog, and there are many individual dogs. What makes them individuals—in Thomas’ lingo, what makes them “numerically distinct”—is their matter. This dog’s matter is distinct from that dog’s.

Angels are different. Angels are pure spirit with no admixture of matter. Each angel has its immaterial form, which is, indeed, its species. So how do you get multiple individuals within a single species, when there’s no matter to individuate them? The answer is, you don’t. Each angel is alone in its species.

And then you’ve got humans, who are individuated by matter, as animals are, but have an intellectual (and hence immaterial) soul, as angels do. All humans manifestly are of the same species: they share a single essence, a single nature, which gives them their form. And we say that the soul is the form of the body. Since apparently you only get one intellectual substance per species (as with angels) and one essence, one species, for all individuals within that species, this led some thinkers to suggest that human beings share a single soul, a single intellect. We appear to be many, but in our inmost selves, we are all one.

Thomas stoutly disagrees: as we have immortal souls, our souls, shorn of our bodies, must remain individuals. (Uncle Screwtape was right: human beings are weird.)

In my next post, I’ll begin working through the objections.

A necessary consequence of the foregoing doctrine is that the intellect whereby man understands is incorruptible.

By “incorruptible,” Thomas means that the intellect cannot pass away, cannot die. Natural things are generated, they come to be, and they are corrupted, they pass away. They are born, and they die. The intellect does not. Thomas goes on to show this in several ways.

Every being acts in a way that is conformable to its existence. The intellect has an activity which it does not share with the body, as we have proved. This shows that it can act by itself. Hence it is a substance subsisting in its own being. But, as was pointed out above, intellectual substances are incorruptible. Accordingly the intellect whereby man understands is incorruptible.

As shown previously, the action of the intellect is immaterial; and since every being’s action is conformable with its existence, the intellect’s existence must be immaterial as well—it “subsists in its own being.” That is, it’s an intellectual substance, and such cannot die.

Again, the proper subject of generation and corruption is matter. Hence a thing is immune to corruption to the extent that it is free from matter. Things composed of matter and form are per se corruptible; material forms are corruptible indirectly (per accidens), though not per se. Immaterial forms, which are above material conditions, are wholly incorruptible. The intellect by its very nature is elevated completely beyond matter, as its activity shows: we do not understand anything unless we separate it from matter. Consequently the intellect is by nature incorruptible.

Looked at another way, to be corruptible is to be material. A material object is composed of matter and form; the form gives form to the matter. An oak tree is matter with the form of an oak tree. Oak trees can die; and thus, indirectly, the tree’s form can die as well. Oak trees have no intellect, and no immaterial activity, and so the form must pass away with the matter.

But the intellect is an immaterial form, as it deals with forms as separated from matter and must be immaterial to do so.

Moreover, corruption cannot take place without contrariety; for nothing is corrupted except by its contrary. This is why the heavenly bodies, which do not admit of contrariety, are incorruptible. But all contrariety is far removed from the nature of the intellect, so much so that things which are contraries in themselves, are not contraries in the intellect. The intelligible aspect of contraries is one, inasmuch as one thing is understood in terms of another. Thus it is impossible for the intellect to be corruptible.

This last bit I had to think about for a while. “…nothing is corrupted except by its contrary.” What on earth does that mean?

Two propositions, A and B, are contraries if they cannot both be true. An oak tree exists; it dies; it no longer exists. There is no longer an oak tree. Those two statements are certainly contrary: there is an oak tree here, there is not an oak tree here. But I still think there’s something I’m missing about contraries and corruption.

But the point that Thomas is making about contraries is that although the propositions A and B cannot both be true in reality, and cannot coexist in fact, they can coexist perfectly well in my intellect. I am quite capable of holding both propositions in my mind at once—in fact, I must do so just to note that they are contraries. Thus, “contrariety is far removed from the nature of the intellect.” And since corruption requires contrariety, the intellect cannot be corruptible.

Here’s what Thomas has to say:

This discussion brings out the truth that knowledge of things in our intellect is not caused by any participation or influence of forms that are intelligible in act and that subsist by themselves, as was taught by the Platonists and certain other philosophers who followed them in this doctrine. No, the intellect acquires such knowledge from sensible objects, through the intermediacy of the senses.

Thomas, like Aristotle, is no Platonic Idealist. Plato said that when we see a dog we remember Dog…but no, the intelligible species Dog doesn’t exist on its own, floating out there in space somewhere. We learn what it is to be a Dog by studying real dogs.

However, since the forms of objects in the sense faculties are particular, as we just said, they are intelligible not in act, but only in potency. For the intellect understands nothing but universals. But what is in potency is not reduced to act except by some agent. Hence there must be some agent that causes the species existing in the sense faculties to be intelligible in act.

I see this dog, Fido; how do I get from this particular, this dog, this Fido, to Dog, an understanding of Dog in general? There’s no effect without a cause, and especially an efficient cause, an agent. The agent in this case is me, of course; I’m the one who’s learning what a Dog is. But I see with my eyes, I manipulate with my hands; I must have some faculty which performs this translation from particular to universal. What is it?

The possible intellect cannot perform this service, for it is in potency with respect to intelligible objects rather than active in rendering them intelligible.

The possible intellect is like a storehouse for intelligible species. As such, it’s part of my memory, as the term is commonly used.

Therefore we must assume some other intellect, which will cause species that are intelligible in potency to become intelligible in act, just as light causes colors that are potentially visible to be actually visible. This faculty we call the agent intellect, which we would not have to postulate if the forms of things were intelligible in act, as the Platonists held.

I suppose that it’s due to Thomas’ analogy, here, that we refer to the “natural light of reason”.

To understand, therefore, we have need, first, of the possible intellect which receives intelligible species, and secondly, of the agent intellect which renders things intelligible in act. Once the possible intellect has been perfected by the intelligible species, it is called the habitual intellect (intellectus in habitu), for then it possesses intelligible species in such a way that it can use them at will; in other words, it possesses them in a fashion that is midway between pure potency and complete act.

What I understand him to be saying is this, as I diagrammed it above. The intelligible species enters my intellect in pure potency, as perhaps when I have seen dogs but not regarded them, not reflected upon them. And then, it strikes me that I’ve been seeing these odd furry things about, and I realize that they are all more or less similar. I reflect upon the sense impressions, and I—my agent intellect—bring the intelligible species Dog into full act. My possible intellect now has the species in full, indeed, is the species for that moment:

But when it has these species in full actuality, it is called the intellect in act. That is, the intellect actually understands a thing when the species of the thing is made the form of the possible intellect. This is why we say that the intellect in act is the object actually understood.

After a moment, I contemplate something else, a passing car, perhaps, and forget about dogs. But I have changed. With regard to dogs, my possible intellect is now my habitual intellect: I have the species Dog in a way I previously didn’t. And I can call it to mind and understand in act whenever I choose. In short, I have learned what a dog is.

Or, in other words, I see a brown furry object with a particular configuration of features, and I say, “That’s a dog!”

So, Thomas says:

However, we must realize that forms in corporeal things are particular, and have a material existence. But in the intellect they are universal and immaterial.

Here is a dog that I see and pet. I sense the form dog as this particular material dog, but I apprehend it as a universal, immaterial species.

Our manner of understanding brings this out. That is, we apprehend things universally and immaterially. This way of understanding must conform to the intelligible species whereby we understand.

Right.

Consequently, since it is impossible to pass from one extreme to another without traversing what lies between, forms reaching the intellect from corporeal objects must pass through certain media.

Material dog Spot there in the room, immaterial species Dog here in my head. The form dog has to get in here from out there. So what’s in the middle?

These are the sense faculties, which receive the forms of material things without their matter; what lodges in the eye is the species of the stone, but not its matter.

In other words, seeing a stone and having a stone in my eye are two very different things. The latter hurts, the former doesn’t.

However, the forms of things received into the sense faculties are particular; for we know only particular objects with our sense faculties.

I don’t see the species Dog; I see this particular dog. Iperceive its color and shape with my eyes, the texture of its fur with my touch, and its need for a bath with my nose. (Come to think of it, I problem sense that through the texture of its fur as well.) These forms are all particular, and apply to this particular dog. They are all accidental forms: I do not sense the dog’s substance, but only its accidents. Then, my intellect somehow operates on those accidental forms to perceive a substance, a body, an animal, a dog.

Hence man must be endowed with senses as a prerequisite to understanding. A proof of this is the fact that if a man is lacking in one of the senses, he has no knowledge of sensible objects that are apprehended by that sense. Thus a person born blind can have no knowledge of colors.

And if I lack a particular sense, I don’t perceive the related forms.

As was stated above, the higher an intellectual substance is in perfection, the more universal are the intelligible forms it possesses. Of all the intellectual substances, consequently, the human intellect, which we have called possible, has forms of the least universality. This is the reason it receives its intelligible forms from sensible things.

When an intellect understands something, it understands by possessing the essence–the form–of that thing. That’s what Thomas means by “intelligible form”–the kind of form that can be apprehended by the intellect. The human intellect, being the least possible kind of intellect, has the most particular, least universal forms, which as he says are received from sensible things. I look at a dog, and apprehend Dog.

This can be made clear from another point of view. A form must have some proportion to the potency which receives it. Therefore, since of all intellectual substances man’s possible intellect is found to be the closest to corporeal matter, its intelligible forms must, likewise, be most closely allied to material things.

When I apprehend Dog, I am apprehending the essence–the form–of the dog. Now, it is precisely this form that makes the dog a Dog. It is this form that turns the matter of which the dog is made into that which we call a Dog. And consequently this form, Dog, is proportional to matter, that is, it’s a form that is suitable for bringing the potency of matter to that kind of act we call a Dog.

However, it’s also a form that is intelligible to the human intellect. It’s suitable for forming matter into a dog, and for forming my intellect into the concept Dog. This makes sense, because we’ve already determined that all of intellectual substances, the human intellect is closest to matter.

Good grief, I think I’m actually beginning to understand this stuff.

Since intellectual being is superior to sentient being, just as intellect is superior to sense, and since lower beings imitate higher beings as best they may, just as bodies subject to generation and corruption imitate in some fashion the circulatory motion of heavenly bodies, it follows that sensible beings resemble, in their own way, intellectual beings. Thus from the resemblance of sense to intellect we can mount to some knowledge of intellectual beings.

A sentient being is a being that possesses sense, i.e., vision, hearing, and so forth. Animals are sentient; plants are not. Humans are sentient but also intellectual. Now, all beings resemble some perfection or perfections in God, and the higher the being, the more so. Thus, Thomas may say that lower beings imitate higher beings “as best they may”. Since sentient beings resemble, in some sense, intellectual beings, we can learn something about how intellect works in Man by studying how sense works in Dog.

However, “sentient being” is not the same as “sensible being”. A sentient being is a being that has sense; a sensible being is a being that can be sensed.

In sensible beings a certain factor is found to be the highest; this is act, that is, form. Another factor is found to be the lowest, for it is pure potency; this is matter. Midway between the two is the composite of matter and form.

OK, sure. Rocks, plants, animals, people, are all a composite of form and matter.

We expect to find something similar in the intellectual world. The supreme intellectual being, God, is pure act. Other intellectual substances have something of act and of potency, but in a way that befits intellectual being. And the lowest among intellectual substances, that whereby man understands, has, so to speak, intellectual being only in potency.

Interesting. At the top end of the intellectual scale, we have God, who is pure act; then we scale down through the angels, in whom is some admixture of potency (though no matter), until finally the lowest creatures on the intellectual scale, the souls of men and women, have intellect in potency only. That makes sense.

Hey, wait a minute. Potency only? But how can I understand anything, if my intellect is only potentially there?

This is borne out by the fact that man is at first found to be only potentially intelligent, and this potency is gradually reduced to act in the course of time.

Aha! We learn! Babies understand nothing. Over time we become more intelligent, that is, we understand more things, more essences become intelligible to us. At birth, our intellect is capable of understanding, but we know nothing; when we are grown, presumably we’ve learned something.

And this is why the faculty whereby man understands is called the possible intellect.

Some background I picked up somewhere. The intellect has two parts, the agent intellect and the possible intellect. The agent intellect is that by which we apprehend the essence of something. When I see a dog and think, “That’s a dog,” it is the agent intellect at work. The possible intellect, as I understand it, is like the intellect’s memory. If I see a dog, and I’ve never seen or heard of a dog before, I apprehend it as some kind of animal I’ve never seen before. Gradually, as I learn about dogs, all of the things that go along with being a dog accumulate in the possible intellect and become available to be apprehended. Then, when I see a dog I can move quickly from “this animal before me” to “Man’s best friend.”

Infinite progression is impossible in any series. Among intellectual substances, one must ultimately be found to be supreme, namely, the one which approaches most closely to God. Likewise, one must be found to be the lowest, and this will be the most intimately associated with corporeal matter.

One of the interesting things about reading Thomas is that over time you begin to see certain general principles used over and over again. Some one should search them out and compile them into a book; this would be a great beginning to the hypothetical volume I’ve dubbed “Things St. Thomas Aquinas Took For Granted.” That infinite progression is impossible in any series is undoubtedly one of these.

One of Thomas’ assumptions, I gather, is that nothing created is truly infinite. There are a great many atoms in the universe, for example, far too many for any human being to count, but the total remains is a finite number. So, if you’ve got a finite number of intellectual substances, and they can be ranked by how closely they approach God, then certainly you’re going to have a greatest and a least.

And the least will be associated most intimately with corporeal matter–and that’s us. We’re kind of like amphibians, as Uncle Screwtape describes us, having both material and intellectual (i.e., spiritual) components.

This can be explained in the following way. Understanding is proper to man beyond all the other animals. Evidently, man alone comprehends universals, and the relations between things, and immaterial objects, which are perceptible only to the intelligence.

We, alone among animals, have intellect. Intellect, it develops, is necessarily an immaterial faculty:

Understanding cannot be an act performed by a bodily organ, in the way that vision is exercised by the eye. No faculty endowed with cognitive power can belong to the genus of things that is known through its agency. Thus the pupil of the eye lacks color by its very nature. Colors are recognized to the extent that the species of colors are received into the pupil; but a recipient must be lacking in that which is received.

As always, Thomas’ when Thomas draws examples from physics, astronomy, or biology you have to be very careful. This is an interesting one, though—because the pupil is, in fact, the lens of the eye, and indeed to do its just it must be transparent, lacking in color. That said, he certainly hasn’t proved this principle through this example. The retina, on the other hand, certainly are colored. You can’t taste your own tongue, but you can certainly taste someone else’s. (Ahem.) And anyone who has had their ears ring knows that ears can produce sounds that can be heard.

On the other hand, an eye that sees mostly itself (as with glaucoma) or an ear that hears mostly itself (as with serious tinnitus) or a tongue that tasted mostly itself (ewwww) wouldn’t be all that useful.

The intellect is capable of knowing all sensible natures.

That is, it can apprehend the essences of the things we see/hear/taste/smell/feel.

Therefore, if it knew through the medium of a bodily organ, that organ would have to be entirely lacking in sensible nature; but this is impossible.

Hmmm. Clearly, any bodily organ has a sensible nature; I’ll buy that. Now presumably a sensible nature is the species of a being that can be sensed. And unlike accidents, such as color, which can be possessed to a greater or lesser degree, a being has a species or it doesn’t, all or nothing. Your cornea can have the slightest bit of clouding, in which case you’ll see less perfectly but you won’t be totally blind; but your intellect can’t have just the slightest bit of sensible nature; it either does or it doesn’t.

So a thing can have or not have a sensible nature; and Thomas is claiming that if it has one, it cannot apprehend sensible natures; it’s own sensible nature would get in the way.

How come? I can see it by analogy to sight, but that’s not a proof.

Moreover, any cognitive faculty exercises its power of knowing in accord with the way the species of the object known is in it, for this is its principle of knowing. But the intellect knows things in an immaterial fashion, even those things that are by nature material; it abstracts a universal form from its individuating material conditions. Therefore the species of the object known cannot exist in the intellect materially; and so it is not received into a bodily organ, seeing that every bodily organ is material.

This bit makes more sense. A universal clearly is not material; so it can’t exist materially; and since every bodily organ is material, the apprehended universal doesn’t exist in any bodily organ.

Now, there’s an obvious question I think any programmer would ask, here. What’s the difference between, say, an architect’s concept of a building he’s designing, as it exists in his intellect, and the CAD model of the building, as it exists in a computer’s memory? The CAD model is an immaterial thing, a collection of related ideas; but it’s captured as patterns of 0′s and 1′s.

You could ask a similar question about a printed book. There are certainly ideas in the book, in the form of letters made of ink. A book is a material thing containing immaterial ideas, but those ideas are captured materially. Why could there be a bodily organ (i.e., the brain) that works the same way?

I think the answer is that the book does not understand itself; the computer does not understand the program within it. The ideas in a book or in a computer program or in a CAD model really only come to life in the intellect of the author or the programmer. They are physical tools that borrow the immaterial intellect they need from them what has it.

The same is clear from the fact that a sense is weakened and injured by sensible objects of extreme intensity. Thus the ear is impaired by excessively loud sounds, and the eye by excessively bright lights. This occurs because the harmony within the organ is shattered. The intellect, on the contrary, is perfected in proportion to the excellence of intelligible objects; he who understands the higher objects of intelligence is able to understand other objects more perfectly rather than less perfectly.

Sense organs are weakened by inputs of extreme intensity, but the greather than objects the intellect understands, the more it is strengthened. And things that are “over your head” don’t weaken your intellect (even though people say, “that makes my brain hurt”)—they just go over your head.

Consequently, if man is found to be intelligent, and if man’s understanding is not effected through the medium of a bodily organ, we are forced to acknowledge the existence of some incorporeal substance whereby man exercises the act of understanding.

Yeah, well, we knew he was going there. :-)

For the substance of a being that can perform an action by itself, without the aid of a body, is not dependent on a body. But all powers and forms that are unable to subsist by themselves without a body, cannot exercise any activity without a body. Thus heat does not by itself cause warmth; rather a body causes warmth by the heat that is in it. Accordingly this incorporeal substance whereby man understands, occupies the lowest place in the genus of intellectual substances, and is the closest to matter.

And there you are. We sit right on the dividing line between the fleshly and the spiritual, and fall into both groups. And therein naturally comes our importance as creatures: God needs us not, and yet we are perfectly designed to be his ambassadors to the rest of the material universe.

It remains to speak of property and accident, for how property differs from species, difference, and genus, has been stated. It is common then to property and inseparable accident not to subsist without those things in which they are beheld, for as man does not subsist without risible, so neither can Ethiopian subsist without blackness, and as property is present to every, and always, so also is inseparable accident. Nevertheless, they differ, in that property is present to one species alone, as the being risible to man, but inseparable accident, as black, is present not only to an Ethiopian, but also to a crow, to a coal, to ebony, and to certain other things. Moreover, property is reciprocally predicated of that of which it is the property, and is equally (present), but inseparable accident is not reciprocally predicated, besides, the participation of properties is equal, but of accidents one (subject partakes) more, but another less. There are indeed other points of community, and peculiarity of the above-mentioned (predicables), but these are sufficient for their distinction, and the setting forth of their agreement.

There’s nothing really new here; all of these points have been made previously. What it comes down to is this: a property is a necessary consequence of the essence of the thing, and applies only to that species, and is always present, whereas accidents, even inseparable accidents, can be more or less present, and are not a necessary consequence of the essence of the thing.

Now, Porphyry says that a property is a property of one species alone. And yet some species are genera in their own right. In Porphyry’s scheme, for example, man is a genus within which divinity is a species: the gods are immortal men. And surely these gods, being rational, would also be able to laugh. So to say that a property is a property of one species alone is true, but misleading: it is predicated of all individuals that belong to that species, whether directly of through some subspecies.

Anyway, that’s it; we’re done with Porphyry! And there was great rejoicing!

To species and accident it is common to be predicated of many, but other points of community are rare, from the circumstance of accident, and that to which it is accidental, differing very much from each other. Now, the properties of each are these: of species, to be predicated of those of which it is the species, in respect to what a thing is, but of accident, in reference to what kind a thing is of, or how it subsists. Likewise, that each substance partakes of one species, but of many accidents, both separable and inseparable: moreover, species are conceived prior to accidents, even if they be inseparable, (for there must be subject, in order that something should happen to it,) but accidents are naturally adapted to be of posterior origin, and possess a nature adjunctive to substance. Again, of species the participation is equal, but of accident, even if it be inseparable, it is not equal; for an Ethiopian may have a colour intense, or remitted, according to blackness, with reference to an(other) Ethiopian.

And there you go; species and accident have almost nothing in common.

I’m pleased to see that my conjecture about “intension and remission” was correct.

One more chapter, and back to St. Thomas!

In what respect species differs from genus and difference, was explained in our enunciation of the way in which genus, and also difference, differ from the rest; it now remains that we should point out how it (species) differs from property and accident.

OK.

It is common then to species and property, to be reciprocally predicated of each other, since if any thing be man, it is risible, also if it be risible, it is man, still we have frequently declared that risible must be assumed according to natural adaptation to risibility.

Right. Men are naturally able to laugh, even if this man never laughs, or has suffered an injury so that he physically is unable to laugh.

It is also common (to them) to be equally present, for species are equally present to their participants, and properties to the things of which they are properties, but species differs from property, in that species indeed may be the genus of other things, but property cannot possibly be the property of other things.

I’ll note (again) that Porphyry is taking property in the narrowest possible sense, here.

Again, species subsists prior to property, but property accedes to species, for man must exist, in order that risible may: besides, species is always present in energy with its subject, but property sometimes also in capacity, for Socrates is a man always in energy, but he does not always laugh, though he is always naturally adapted to be risible.

I’ve not run into this use of the words “energy” and “capacity”, but I suspect he means something like “act” and “potency”. Though that’s not quite right either; the species “man” is present in a baby, but the baby isn’t fully a man in act yet. Nevertheless, it’s clear enough what he means.

Once more, things of which the definitions are different, are themselves also different, but it is (the definition) of species to be under genus, and to be predicated of many things, also differing in number, in respect to what a thing is, and things of this kind, but of property it is to be present to a thing alone, and to every individual and always.

Um, what?

(Two more chapters!)

To difference and accident it is common to be predicated of many things, but it is common (to the former) with inseparable accidents to be present always and with every one, for biped is always present to man, and likewise blackness to all crows. Still they differ in that difference indeed comprehends but is not comprehended by species; for rational comprehends divinity and man, but accidents after a certain manner comprehend from their being in many things, yet in a certain manner are comprehended from the subjects not being the recipients of one accident, but of many. Besides, difference indeed does not admit of intension and remission, but accidents accept the more and less; moreover contrary differences cannot be mingled, but contrary accidents may sometimes be mingled. So many then are the points common and peculiar to difference and the others.

What it comes down to is, the difference has a special relationship to the species of which it is the difference, and to any sub-species of that species, whereas accidents do not, generally speaking. Further, the difference is an all-or-nothing kind of thing; a thing has it or doesn’t, either the thing is this kind of thing or it isn’t. Accidents can generally come and go, and can be had to a greater or lesser degree, and can be commingled: a crow that is spattered with white paint is both black and white at the same time, and an albino crow (if such things exist) is white and not black, but remains a crow.

(Only three more chapters to go, and we can get back to St. Thomas!)

Difference also and property have it in common to be equally shared by their participants, for rational are equally rational, and risible (equally) risible (animals). Also it is common to both to be always present, and to every one, for though a biped should be mutilated, yet (the term biped) is always predicated with reference to what is naturally adapted, since also risible has the “always” from natural adaptation, but not from always laughing. Now, it is the property of difference, that it is frequently predicated of many species, as rational of divinity and man, but property (is predicated) of one species, of which it is the property. Difference moreover follows those things of which it is the difference, yet does not also reciprocate, but properties are reciprocally predicated of those of which they are the properties, in consequence of reciprocating.

The primary difference between the two is that a property of a species (in the strictest sense) is predicated only of that one species, whereas a difference can be predicated of many species. Thus, properties in this sense are reciprocal: if A can laugh then A is a man, and if A is a man then A can laugh. It seems to me, though, that property is more frequently used in the wider sense, where it is not necessarily confined to one species.

Note that properties concern the nature of the being, not the current state of the being. If I lose a leg in an accident, I am still naturally a biped; indeed, were I born with one leg, I would still naturally be a biped. A man who never laughs is still able to laugh by nature.

(Apologies for the lack of posts over the last few days, by the way.)

It is common then to difference and species to be equally participated, for particular men partake equally of man, and of the difference of rational.

Well, yeah: since the difference is part of the definition of the species.

It is also common always to be present to their participants, for Socrates is always rational, and always man, but it is the property of difference indeed to be predicated in respect to what kind a thing is of, but of species in respect to what a thing is, for though man should be assumed as a certain kind of thing, yet he will not be simply so, but in as far as differences according to genus constitute him.

A man’s species says what he is; but the chain of differences leading up the chain of genera to the category of substance indicate what kind of thing he is: a rational, animate, living body.

Besides, difference is often seen in many species, as quadruped in many animals, different in species, but species is in the individuals alone, which are tinder the species.

There are many species of which a particular difference can be predicated.

What “tinder the species” means, here, I cannot say; I have to assume that it’s a typographical error. But anyway, the only beings of which a particular species can be predicated are the individuals within the species.

Moreover, difference is prior to the species which subsists according to it, for rational being subverted, co-subverts man, but man being subverted, does not co-subvert rational, since there is still divinity. Further, difference is joined with another difference, (for rational and mortal are joined for the subsistence of man,) but species is not joined with species, so as to produce some other species; for indeed a certain horse is joined with a certain ass, for the production of a mule, but horse simply joined with ass will not produce a mule.

Remember, again, that for Porphyry a god is an immortal man. Thus, to say that Zeus isn’t a man doesn’t imply that Zeus isn’t rational, but saying that Zeus isn’t rational implies that Zeus isn’t a man.