Archive for the ‘Compendium Theologiae’ Category

CT 85: Unity of the Possible Intellect (Part I)

Tuesday, April 28th, 2009

Uncle Screwtape describes human beings as an amphibious combination of matter and spirit, of animal and angel. Thomas’ topic in this chapter is the precise nature of this amphibious combination. He clearly thinks it is of the first importance: this is the first chapter I’ve run into in the Compendium Theologiae that reads like an article from its big brother, the Summa Theologiae, complete with objections, a sed contra, and answers to the objections.

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.

CT 84: Incorruptibility of the Human Soul

Saturday, April 25th, 2009

In the previous section, Thomas discussed the nature of the human intellect, and its division into the possible intellect, a kind of storehouse of things we’ve understood in the past, and the agent intellect, our capacity to actively bring these things to mind. Now he’s moving on from this to the incorruptibility of the human soul. He says,

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.

CT 83: Necessity of the Agent Intellect

Sunday, March 22nd, 2009

Chapter 83 of the Compendium Theologiae explains why part of our intellectual armamentarium is called the agent intellect; but it’s also an outstanding summary of how we learn. Here’s a diagram I made after reading the chapter; you might want to refer to it as we go along.


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.

CT 82: Man’s Need of Sense Faculties for Understanding

Wednesday, March 11th, 2009

It’s been a while, so let’s recap. We understand with our intellect; we sense with our senses. All that know comes from our senses…but based on what we sense, our intellect apprehends the intelligible species of that which we sense.

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.


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.

CT 81: Reception of Intelligible Forms in the Possible Intellect

Thursday, February 19th, 2009

In Chapter 81, Thomas says,

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.

CT 80: Different Kinds of Intellect and Ways of Understanding

Sunday, February 15th, 2009

Now that we’ve put Man in his place, let’s continue examining human intellect in Chapter 80:

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.”

CT 79: Inferiority of Man’s Intellectual Nature

Saturday, February 14th, 2009

So now we come back to Thomas’ Compendium of Theology, which you may have seen published as Aquinas’ Shorter Summa (not to be confused with A Shorter Summa, which is one of Peter Kreeft’s two abridgements of the full Summa Theologiae). Previously we were looking at the intellectual substances, i.e., angels; now we move on to Man’s intellectual nature in Chapter 79:

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.

CT 78: Order and Degree in Intellectual Operation

Tuesday, October 7th, 2008

So we have a variety of intellectual substances–e.g., angels–each of which is in a species of its own, with its own distinct nature; and Thomas gives me the definite impression that these substances are strictly ordered. In Chapter 78, Thomas avers that just as the substances are ordered from greatest to least, so their intelligence, their ability to understand, is ordered from greatest to least:

Since the nature of a being’s activity is in keeping with its substance, the higher intellectual substances must understand in a more perfect way, inasmuch as they have intelligible species and powers that are more universal and are more unified. On the other hand, intellectual substances that are less perfect must be weaker in intelligence, and must have species that are more numerous and less universal.

It’s not quite clear to me what Thomas is getting at, describing species as “more universal and more unified” on the one hand, and as “more numerous and less universal” on the other. I have to assume that he is presuming that there are multiple genera of intellectual substances, and that some genera contain a few species while others contain many species; and that the few species are more universal in that their definitions are simpler, with fewer conditions, while the many are less universal, and more specific. This is consistent with what else we’ve seen: God is most universal, infinitely perfect, and One; individual men are particular, not notably perfect, and many. So there’s a scale here.

I think this is probably an example of Thomas glossing over the details for the sake of simplicity.

CT 77: Order and Degree among Intellectual Beings

Wednesday, October 1st, 2008

OK; so what kinds of intellectual beings are there? Thomas tells us in Chapter 77:

Intellectual substances are superior to other substances in the scale of perfection.

We covered this last time.

These same substances must also differ from one another in degree. They cannot differ from one another by material differentiation, since they lack matter; if any plurality is found among them, it must be caused by formal distinction, which establishes diversity of species.

All members of a species have the same nature, or essence; they differ in their accidents, and in the matter they contain, matter being the principle of individuation. (I’m coming to like that phrase a whole lot.) Not containing any matter, angels must all be unique, that is, every angel must be different in essence than ever other angel. That is, every angel must be in a species by itself. I’m using the term angel loosely; not ever intellectual being is an angel, strictly speaking.

In beings that exhibit diversity of species, the degree and order existing in them must be taken into consideration. The reason is that, just as addition or subtraction of a unit causes variation of species in numbers, so natural entities are found to vary in species by the addition or subtraction of differences.

To get two different species, you need a specific difference between them. To get more species, you need to add or subtract differences, so that each is unique.

For instance, what is merely alive, differs from what is both alive and endowed with sense perception; and the latter differs from what is alive, endowed with sense, and rational. Therefore the immaterial substances under discussion must be distinct according to various degrees and orders.

This seems to imply that there is an absolute ranking among angels; I’m not sure that follows. In Thomas’ example, plants have life, animals have life and sense, and humans have life, sense, and intellect. We’re adding an additional predicate each time. But it needn’t be that way.

Consider four angels A, B, C, and D, and three predicates x, y, and z.

A is x
B is x and y
C is x and z
D is x and y and z

D is strictly greater than A, B, and C. B and C are both greater than A.
But is B greater than C? Or is it vice versa? Or are they not commensurate?

In other words, might the order among angels be a partial ordering? And if not, why not?

CT 76: Freedom of Choice in Intellectual Substances

Monday, September 29th, 2008

Thomas has established that there are incorporeal beings, and that these beings are intellects. In Chapter 76, he shows that they must have free will.

This fact shows that such beings have freedom of choice.

That is, that such beings are intellects.

The intellect does not act or desire without forming a judgment, as lifeless beings do, nor is the judgment of the intellect the product of natural impulse, as in brutes, but results from a true apprehension of the object. For the intellect perceives the end, the means leading to the end, and the bearing of one on the other. Hence the intellect can be the cause of its own judgment, whereby it desires a good and performs an action for the sake of an end. But what is a cause unto itself, is precisely what we call free. Accordingly the intellect desires and acts in virtue of a free judgment, which is the same as having freedom of choice. Therefore the highest substances enjoy freedom of choice.

In other words, unlike animals, which are more-or-less programmed to act in ways that are good for them, intellects can perceive a good, can perceive what steps to take to achieve that good, and can then will to take take those steps based on its judgement. It can thereby cause itself to take those steps; and as I emphasized in the passage above, that’s precisely what it means to be free: to be able to cause oneself to do one thing or another.

Furthermore, that is free which is not tied down to any one definite course. But the appetite of an intellectual substance is not under compulsion to pursue any one definite good, for it follows intellectual apprehension, which embraces good universally. Therefore the appetite of an intelligent substance is free, since it tends toward all good in general.

In other words, there are many goods to choose from, and the intellect is free to choose from among them.

This is an interesting point. Peter Kreeft points out that we must have free will, even in Heaven; which means that we must have choices, all of which are good. Where there is only one good choice, and with sin being entirely in the past (thus eliminating the ability to make bad choices), there can be no free will. So we will have choices of good things in Heaven.

You’ll hear people say, “God has an amazing plan for your life.” I’ve always taken this to mean that God has some particular path He wants me to follow: not just in general, to Him, but in every specific. And that, if I were to truly turn to Him and obey all His promptings, that’s the path I’d follow. But apparently that’s not the case. All good roads lead to God, and Christ is the Way; but Christ is God and God is infinite. There are apparently many ways I can choose to serve God, all of which are good. I must follow God, no matter what way I go, but it’s neat to think that it isn’t all scripted, and that He lets me participate in it in a very real way.

But I digress.