DE&E: Chapter 3:1

As Chapter 3 of De Ente et Essentia opens, we get to think see just how the term essence relates to the genus, species, and difference we’ve been discussing.

Having seen what the term essence signifies in composite substances, we ought next see in what way essence is related to the logical intentions of genus, species, and difference.

I still haven’t quite come to grips with the use of the term intention in this context. But genus, species, and difference are three of the five “predicables”, the five kinds of things which may be predicated of a substance, though I venture to guess that in this context, as intentions, Thomas is referring to them as subjects rather than as predicates.

Since that to which the intentions of genus or species or difference is appropriate is predicated of this signate singular, it is impossible that a universal intention, like that of the species or genus, should be appropriate to the essence if the genus or species is signified as a part, as in the term humanity or animality.

Socrates has humanity; but he also has matter. If we wish to say that Socrates is a man, the notion of “a man” needs to include matter, even if non-signate. Humanity is the special form of man, but as man is a composite of form and matter, it’s only part.

The other day, I suggested that this is the distinction between comprehension and extension of a term. The comprehension of a term is its meaning, a set of predicates, and the extension of a term is the set of things to which it refers. But I don’t think that’s right. Thomas is doing something different here.

Thus, Avicenna says, Metaphysicae V, cap. 6, that rationality is not the difference but the principle of the difference. For the same reason, humanity is not a species, and animality is not a genus.

Rather, “man” is the species, and humanity the special form.

Similarly, we cannot say that the intention of species or genus is appropriate to the essence as to a certain thing existing beyond singulars, as the Platonists used to suppose,….

The exact sense of the words Thomas is using here eludes me no matter how I look at it; but what he’s talking about are the Platonic Ideas: the notion that the ideas of Humanity and Animality and (for all I know) Chairness exist all by themselves, independent of any particular Human or Animal or Chair or any mind to know them. Thomas doesn’t buy this idea, and why?

…for then the species and the genus would not be predicated of an individual: we surely cannot say that Socrates is something that is separated from him, nor would that separate thing advance our knowledge of this singular thing.

We wish to know Socrates. If Humanity exists wholly apart from Socrates, then in what way can knowing Humanity tell us anything about Socrates?

And so the only remaining possibility is that the intention of genus or species is appropriate to the essence as the essence is signified as a whole, as the term man or animal implicitly and indistinctly contains the whole that is in the individual.

I don’t quite see what Thomas means by “the intention of species is appropriate to the essence as the essence is signified as a whole”. Or, rather, I think I know what he means: he means that a thing’s species describes a thing’s essence when you consider essence as defining the whole of the thing, not just its form. I don’t see why he used the exact words he used.

3 Responses to “DE&E: Chapter 3:1”

  1. I think it’s sometimes helpful to try to state what is unclear as narrowly as possible. I tried to put my finger on some difficulties in this passage in five questions:

    1. Why is Thomas concerned to show the way essence is related to logical intentions?

    2. To what is it appropriate to apply “the intentions of genus or species or difference”?

    3. How is “humanity” or “animality” signified as a part?

    4. What the heck is Thomas saying the Platonists supposed?

    5. What are the ways “essence” is signified?

    1. Thomas is relating the three essential predicables (genus, species, difference – the other two (property and accident) are non-essential) to essence itself. A beginner would have covered the Isagoge, an explanation of these five, and probably was wondering how they relate to essence. But essence is said in many ways.

    2. In knowing (not merely sensing, but certainly rooted in sensing) ‘Ryan’, ‘Will’, ‘Phil’, I conceive the intention or concept ‘man’. This intention is brought forth by reflecting on real things existing out there. So ‘man’ is a first intention. But by reflecting on ‘man’, ‘horse’, ‘dog’, I can do the same to them that I did to the individuals above, except my intention or concept is not based in real things existing out there, it’s based on the first intentions. So let’s call it second intention. It is also called logical intention because logic concerns the relations between concepts, and not the concepts themselves. (By the way, is there a third intention? No, because there is no third thing I can base my thoughts on).

    So the intention of genus can be applied to things like ‘man’, ‘horse’, ‘dog’. But all those are applied to signate matter – ie ‘Ryan’, ‘Will’, ‘Phil’ are all man, but they are not humanity, because

    3. (continuing) humanity signifies only a part, namely the principle by which something is a man, but not the whole (which in this case is ‘man’). So humanity is not applied to ‘Phil’.

    4. But Plato supposed a subsisting form apart from the singulars, which leads to many difficulties for our knowledge.

    5. So back to our original question – how is species, as a logical intention, said of essence? It can be said only when essence signifies the whole – ie ‘man’ – and not the part or principle, ie humanity.

    So the original question was, when can an essence be called a species? When the essence in question refers to the whole, and not just to the part. Whereas with Plato it could be said merely of the part, which would bring up a whole bunch of difficulties.

    As a final note, notice the structure of Thomas’ disquisition – first let’s see what the thing (viz. essence) is, then let’s see how it relates to other things. Again and again you find this order, if needed 1) on the knowing subject’s knowledge of the object, 2) whether the object exists, 3) how the object exists, in this order: its genus, its specific difference, its properties, its accidents (like relations to others and so on).

  2. Will says:

    Thanks very much. That last paragraph especially; I’ll have to think about that.

  3. Consider the structure of the Summa as an example (though any particular question will evince the same structure) – first treat on knowledge of God, then treat whether we can know God exists, then whether he exists, and since he exists, let’s consider how he exists (or better how he doesn’t exist), then we’re done with treating him in himself, so let’s go on to his effects insofar as they are related to him, and so on.

    Even the individual questions follow this same structure – consider his treatment of good and evil, or habits, or passions and you find it there too.