Commentaria in Summam contra Gentiles, Liber II

After St. Thomas had determined the question of the production of things, he now determines the question of the distinction of the things themselves ¹. Concerning this, however, he does two things: first, he removes the false opinions of the philosophers; second, he declares the truth, in chapter XLV.

As to the first, he sets out six conclusions, the first of which is given in this chapter, while the rest are given in the following chapters.

I. The first conclusion, therefore, is: The distinction of things is not a matter of chance, that is, it did not come about apart from the intention of the agent.

It is proved first. There are certain substances in whose nature there is no possibility of not being. Therefore such substances are not from chance. Therefore neither will their distinction be from chance. — The first consequence is proved. Because chance does not occur except in things able to be otherwise, as is clear in Book II of the Physics ² — The second is also clear. Because such substances are distinct by their very substance: that is, they have distinction from their own proper rationes.

Second. The case is only in possibles being able to be otherwise. Therefore a distinction that is from matter could perhaps be from chance, but not a distinction that is from form. But the distinction of species is from form, while that of individuals of the same species is from matter. Therefore distinction according to species is not from chance; but perhaps chance is distinctive of certain individuals. Therefore etc. The first consequence is evident, because the principle of that possibility is matter, and not form, which determines the possibility of matter to one.

It must be noted, concerning what Saint Thomas says, that the fall of perhaps some individuals can be distinctive, that he did not say of individuals absolutely, but of some individuals: because in incorruptible individuals, such as intellectual souls and other things of this kind, if there are any other incorruptibles distinct in the same species by number alone, there cannot be a fall, but only in corruptibles.

But he added perhaps: because it is not absolutely true that the distinction of corruptible individuals is from chance; but the distinction of monstrous individuals can be said to be from chance, insofar as they arise beyond the intention of nature. Yet since even monsters are not entirely against the intention of nature, because they are intended by nature at least secondarily, he therefore leaves in doubt whether their distinction is from chance, saying that perhaps chance is the distinguisher of certain individuals.

Third. The first production of things is not from matter. Therefore chance cannot exist in it. But there had to be in it a distinction of things, since many things in created beings are generated neither from one another nor from some one common thing in which they agree. Therefore etc. — The first inference is evident, because chance can occur only in the making of those things that are generated from matter.

Note that Saint Thomas removes two ways in which someone might say that in the first production of things there was no distinction, namely by saying: — either that only one thing was produced, from which another, distinct from it, was later produced by chance, as if only air had been produced, from which fire afterward emerged; — or that one matter was produced, from which several distinct things later sprang forth. He removes both of these by the fact that there are many things which are not generated from one another, by which the first claim is excluded; nor from some one common thing, by which the second is excluded. For the heavens and these lower things, and likewise the intelligences, which do not agree in matter, are generated neither from one another nor from a common matter.

III. Fourth. The distinction of things naturally precedes the motions and operations of things: for determinate effects belong to determinate and distinct things. But the motions and operations of things are from causes per se and determinate. Therefore so is the distinction. Therefore etc. — The consequence is evident, because, since a cause per se is prior to a cause per accidens, it is unfitting to say that posterior things are from a cause per se while prior ones are from a cause per accidens.

Fifth. The universe of creatures is from God acting through intellect and will, in whose power defect cannot occur. Therefore the form of the universe is intended and willed by God. Therefore also the distinction of things. — The first consequence is proved. Because of anything proceeding from an agent acting through intellect and will, the form is intended by that agent: (supply) unless perhaps there were a defect in its power, such that it could fall short of its intention. — The second is also evident. Because the form of the universe consists in the distinction and order of its parts.

IV. Sixth. The order of the parts of the universe and their distinction is the end of the production of the universe. Therefore, etc. — Saint Thomas takes the consequence as evident: because it belongs to the notion of an end, insofar as it is such, that it be intended. — But the antecedent is proved. Because what is good and best in actuality is the end of its own production. Now the best of the universe consists in the order and distinction of its parts. Therefore, etc.

Note that the end is twofold: namely, the end of the operation, and the end of the operator. The end of the operation (that is, that for the sake of which the operation exists) is the best thing produced by the operation. And such a thing is intrinsic to the effect, as its form. Thus the end of the production of the universe is its totality, which consists in the order and distinction of its parts. — But the end of the operator is something that the operator intends from the effect produced: as the house-builder, in producing a house, intends habitation. And such an end is not the best thing that is in the effect produced, but is something extrinsic to the effect. In this way, the order of the parts of the universe is not the end in the production of the universe, but the divine goodness, from love of which God produced the creature, so that that goodness itself might be made manifest. — It is therefore in this sense that Saint Thomas speaks of the end of the operation, and not of the end of the operator, as is clear.

The conclusion is confirmed by the authority of Genesis 1.

But from this is excluded the opinion of the ancient Naturalists, who posited only a material cause, out of which they said all things come to be through rarity and density.

Likewise excluded is the opinion of Democritus and Leucippus, who posited infinite material principles, namely indivisible bodies of the same nature, differing only in figure, position, and order, but denying an agent cause.