Archive for the ‘Isagoge’ Category

Isagoge: Chapter 17 — Of Community and Difference of Property and Accident

Thursday, February 12th, 2009

Property and Accident, compare and contrast:

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!

Isagoge: Chapter 16 — Of Community and Difference of Species and Accident

Wednesday, February 11th, 2009

Species and accident, compare and contrast:

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!

Isagoge: Chapter 15 — Of Community and Difference of Species and Property

Tuesday, February 10th, 2009

Species and property, compare and contrast:

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.


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!)

Isagoge: Chapter 14 — Of Community and Difference of Accident and Difference

Sunday, February 8th, 2009

Accident and difference, compare and contrast:

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!)

Isagoge: Chapter 13 — Of Community and Difference of Property and Difference

Saturday, February 7th, 2009

Property and difference, compare and contrast:

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.

Isagoge: Chapter 12 — The Same Subject Continued

Tuesday, February 3rd, 2009

That is, the Community and Difference of Species and Difference, which Porphyry didn’t quite get to in the chapter by that name.

(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.

Isagoge: Chapter 11 — Of the Community and Difference of Species and Difference

Monday, January 26th, 2009

You’d think, given the title of the chapter, that this would another compare and contrast. Not so. What we get instead is a disquisition on combinatorial math. (Feel free to skip to the bottom.)

We have shown then, wherein genus differs from the other four, but each of the other four happens also to differ from the rest, so that as there are five, and each one of the four differs from the rest, the five being four times (taken), all the differences would appear to be twenty. Nevertheless, such is not the case, but always those successive being enumerated, and two being deficient by one difference, from having been already assumed, and the three by two differences, the four by three, the five by four; all the differences are ten, namely, four, three, two, one. For in what genus differs from difference, species, property, and accident, we have shown, wherefore, there are four differences; also we explained in what respect difference differs from genus, when we declared in what genus differs from it. What remains then, viz. in what respect it differs from species, property, and accident, shall be told, and three (differences) arise. Again, we declared how species differs from difference, when we showed how difference differs from species; also we showed how species differs from genus, when we explained how genus differs from species; what remains then, viz. in what species differs from property and from accident, shall be told: these, then, are two differences. But in what respect property differs from accident, shall be discovered, for how it differs from species, difference, and genus, was explained before in the difference of those from these. Wherefore, as four differences of genus with respect to the rest, are assumed, but three of difference, two of species, and one of property with regard to accident, there will be ten (differences altogether), of which, four we have already demonstrated, viz. those of genus, with respect to the rest.

We have five things, genus, difference, species, property, and accident. We’re going to compare and contrast each pair of these; and once we’ve compared and contrasted A with B, we don’t need to compare and contrast B with A. So there are 10 pairs, rather than 20. Woohoo. In the next chapter, I imagine, we’ll get on with comparing and contrasting difference and species.

Isagoge: Chapter 10 — Of Community and Difference of Genus and Accident

Sunday, January 25th, 2009

Genus and accident, compare and contrast:

It is common to genus and accident to be predicated, as we have said, of many things, whether they (the accidents) be separable or inseparable, for to be moved is predicated of many things, and blackness of crows, and of Ethiopians, and of certain inanimate things. Genus however differs from accident, in that genus is prior, but accident posterior to species, for though an inseparable accident be assumed, yet that of which it is the accident is prior to the accident. Also the participants of genus participate it equally, but those of accident do not equally; for the participation of accidents accepts intension and remission, but not that of genera. Besides, accidents primarily subsist about individuals, but genera and species are by nature prior to individual substances. Moreover, genera are predicated of the things under them, in respect to what a thing is, but accidents in respect to what kind of a thing it is, or how each thing subsists; for being asked, what kind of man an Ethiopian is, you say that he is black; or how Socrates is, you reply that he is sick or well.

One of the things about Aristotelian and Thomistic philosophy that I’ve had trouble wrapping my mind around is the notion of cause. I know what the four causes are: the efficient, the material, the formal, and the final, and I even think I mostly understand what they mean. But when I hear the word “cause”, my mind naturally assumes the efficient cause, often without any conscious decision on my part. Porphyry is helping with this, because he keeps pointing out that this is prior or posterior to that: which is equivalent to saying that this a cause of that or that is caused by this. Thus, genus G is a cause of species S within it; and species S is a cause of individual X which has accident A. The question remains, what kind of causes are these?

It seems to me that X is a material cause of A: if Socrates is sick, Socrates is the matter that is sick. X might be the efficient cause of A as well, as when Socrates is sick because Socrates has just chosen to drink a cup of hemlock. S seems to be the formal cause of X; and is G the formal cause of S? I dunno.

The second emphasized statement is also interesting. All beings which participate in a genus, that is, all beings which belong to the genus or of which the genus may be predicated, belong to it equally. All dogs, all cats, and all humans are animals to the same degree. But accidents support “intension and remission”. I’m not sure what he means by that. He might mean that accidents can come and go, but I don’t think so: for individuals which have a particular accident might have it equally, so far as they have it at all, and individuals which don’t don’t. I think he means that one can have an accident to a degree. A cat can be white, but also more or less white. Socrates can be sick, but also more or less sick, sick with a cold, or sick unto death (thanks to the hemlock).

Isagoge: Chapter 9 — Of the Community and Difference of Genus and Property

Tuesday, January 20th, 2009

Compare and contrast. First, we’ll compare:

Both to genus and to property it is common to follow species, for if any thing be man, it is animal, and if any thing be man, it is risible. Likewise to genus, to be equally predicated of species, and to property, (to be equally predicated) of the individuals which participate it; thus man and ox are equally animal, and Anytus and Melitus risible. It is also common that genus should be univocally predicated of its proper species, and property of the things of which it is the property;

So if A is a member of a species S, then we know immediately that A is a member of the genus G to which the species belongs, and that A has all of the properties P of S. Further, not only is G predicated of all species within it, just as P is predicated of all individuals in S, but each is predicated univocally, that is, in exactly the same way. When we say that all men laugh, the term “laugh” doesn’t have different shades of meaning for different men, but it means the same thing for all men. Similarly, when we say that all men are animals, we mean it in the same way for all men.

And now we’ll contrast.

…still they differ, because genus is prior, but property posterior, for animal must first necessarily exist, afterwards be divided by differences and properties.

You can’t have a species until you have a genus, and you can’t have a property until you have a species.

Also genus indeed is predicated of many species, but property of one certain species of which it is the property.


Besides property is reciprocally predicated of that of which it is the property, but genus is not reciprocally predicated of any thing, for neither if any thing is an animal, is it a man, nor if a thing be animal is it risible, but if any thing is a man it is risible, and vice versa.

From this it is clear that Porphyry’s using the word “property” in its narrowest sense, as we saw in Chapter 4.

Moreover, property is inherent in the whole species, of which it is the property, in it alone, and always, but genus in the whole species indeed of which it is the genus, and always, yet not in it alone;


…once more, properties being subverted do not co-subvert genera, but genera being subverted, co-subvert species, to which properties belong; wherefore, also those things of which there are properties, being subverted, the properties themselves also, are co-subverted.

If being A does not have property P of species S, it might still belong to some other species of genus G. But if being A doesn’t belong to genus G, then it clearly doesn’t have property P.

Isagoge: Chapter 8 — Of Community and Difference of Genus and Species

Saturday, January 17th, 2009

Once again, we compare and contrast. Here’s what Porphyry has to say:

Genus and species possess in common, (as we have said,) the being predicated of many things, but species must be taken as species only, and not as genus, if the same thing be both species and genus. Moreover, it is common to them both to be prior to what they are predicated of, and to be each a certain whole; but they differ, because genus indeed comprehends species, but species are comprehended by, and do not comprehend genera, for genus is predicated of more than species. Besides, it is necessary that genera should be presupposed, and when formed by specific differences, that they should consummate species, whence also genera are by nature prior. They also co-subvert, but are not co-subverted, for species existing, genus also entirely exists, but genus existing there is not altogether species; genera too, are indeed univocally predicated of species under them, but not species of genera. Moreover, genera exceed, from comprehending the species which are under them, but species exceed genera by their proper differences; besides, neither can species become most generic, nor genus most specific.

I’m not going to go through this line by line; instead, I’m going to list the points I take away from it.

Aquinas frequently uses the word aspect, as in, “under the aspect of”. I’ve never felt very clear as to just what he means by it, but reflecting on this passage has helped bring me closer to it. An aspect, I take it, is a way of looking at something, a way of analyzing it. Most things can be looked at in different ways.

Now, genus and species have much in common, because all species but the most specific are also genera, and all genera but the most generic are also species. Take animal, for example, which is a species of body, but a genus containing a vast number of species, including Man. But while most genera are species, and most species are genera, it is not the case that genus and species are the same thing. We can consider body as a genus, and as a species, and these are two different aspects.

OK, so what else do we learn from Porphyry?

  • Genus and species are both predicated of many things.
  • They are prior to that of which they are predicated, that is, they are causes in the Aristotelian sense.
  • They are each a certain whole (I’m not at all sure what this means).
  • A genus is prior to the species within it.
  • Equivalently, a genus is predicated of the species within it, but not vice versa.
  • Given genus G and species S within it, G and S co-subvert; I gather that this means that if X is not an S, then it isn’t a G either, and if it isn’t a G, then it isn’t an S.
  • On the other hand, G and S are not co-subverted; which I gather means that if X is an S you know it’s also a G, but if you know that it’s a G you don’t know whether it’s an S or not.

The talk of genera comprehending species and species not comprehending genera bugs me. As I understand it, the comprehension of a genus or species is what it means; the extension of a genus or species is the collection of beings of which it is predicated. The comprehension of man is wider than that of animal because it takes the comprehension of animal and adds rational to it; whereas the extension of man is narrower than that of animal because all men are animals but not all animals are men.

That latter appears to be what Porphyry is saying, or in other words, that animal includes man, and other species, but man doesn’t include animal in the same way. But I don’t see that this use of “comprehend” aligns with the description I’ve just given.