Commentaria in Primam Partem Summae Theologiae

A clear title. – In the body there are two parts: first, he distinguishes; second, he answers the question raised.

II. As to the first, the divine idea is taken in two ways: as exemplar, and as ratio. – The distinction is made manifest in two ways. First, from the difference between the two offices attributed to the ideas by Plato, to generate and to produce knowledge. Second, from the difference between the speculative and the practical.

III. With respect to second, he answers the question with two affirmative propositions, according to the members of the distinction set out above. The first is: Idea, insofar as it is an exemplar, is of all things made by God at whatever time.—The second is: Idea, as ratio, is of all things that can be made and known according to their proper rationes, both speculative and practical.

These propositions are not otherwise proved in the text itself, since they are evident from q. 14¹ and from what has been said above². Yet you should not overlook the fact that idea, taken as ratio, is understood as the objective ratio, as the text itself explained in the first article³. Therefore an idea is said to be the objective ratio of a thing. In this way too, a Platonic idea would be a ratio of knowing.

IV. In the response to the third, note that here St. Thomas retracts what was said in Qu. de Ver., q. III, art. 5, and in I Sent., dist. XXXVI, in the last article⁴, concerning the idea of prime matter. Nor is there any need to devise glosses, since the middle term here assumed, namely, that it is not knowable in itself, expressly overturns what was said elsewhere, as is clear to one who looks closely.

But a doubt remains here: of what composite is prime matter the idea? If, however, the text is looked at attentively, it will easily become clear that the idea as ratio corresponding to prime matter is the idea of body, which is the genus in the category of Substance; for it would be defined according to its form, if it were to be defined. For the idea as ratio is knowable through its own ratio, as is said in the text ⁵ But the idea of it as exemplar must be sought in no other way than the ideas of genera, concerning which the text says ⁶ that they do not have an idea distinct from the species, etc.