Nevertheless, the nature understood in this way is not a universal notion, because unity and commonality are in the notion of a universal, and neither of these pertains to human nature considered absolutely. For if commonality were in the concept of man, then in whatever humanity were found, there would be found commonality, and this is false, because no commonality is found in Socrates, but rather whatever is in him is individuated. Similarly, the notion of genus or species does not pertain to human nature as an accident arising from the existence that the nature has in individuals, for human nature is not found in individuals according to its unity such that it will be one thing in all the individuals, which the notion of the universal demands. The only possibility, therefore, is that the notion of species pertains to human nature according to the existence human nature has in the intellect.
Human nature has in the intellect existence abstracted from all individuals, and thus it is related uniformly to all individuals that exist outside the soul, as it is equally similar to all of them, and it leads to knowledge of all insofar as they are men. Since the nature in the intellect has this relation to each individual, the intellect invents the notion of species and attributes it to itself. Hence, the Commentator, in De Anima I, com. 8, says, "The intellect is what makes universality in things,"and Avicenna says the same in his Metaphysicae V, cap. 2. Although this nature understood in the intellect has the notion of a universal in relation to things outside the soul (because it is one likeness of them all), as the nature has existence in this intellect or in that one, it is a certain particular understood species. The Commentator, therefore, is in error in De Anima III, com. 5, when he wants to infer the unity of intellect in all men from the universality of the understood form, because the universality of the form does not arise from the existence the form has in the intellect but rather from its relation to things as a likeness of such things. It is as if there were a corporeal statue representing many men; that image or species of statue would have a singular and proper existence insofar as it exists in this matter, but it would have an aspect of commonality insofar as it was a common representative of many.
Since human nature, considered absolutely, is properly predicated of Socrates, and since the notion of species does not pertain to human nature considered absolutely but only accidentally because of the existence the nature has in the intellect, the term species is not predicated of Socrates, for we do not say that Socrates is a species. We would have to say that Socrates is a species if the notion of species pertained to man arising from the existence that the nature has in Socrates or from the nature considered absolutely, that is, insofar as man is man. For whatever pertains to man insofar as he is man is predicated of Socrates.
But to be predicated pertains to a genus per se, because being predicated is placed in its definition. Now, predication is completed by the action of the intellect in compounding and dividing, and it has as its basis the unity of those things one of which is said of another. Hence, the notion of predicability can be subsumed in the notion of this intention that is the genus, which is itself completed by an act of the intellect. Still, when the intellect attributes the intention of predicability to something by compounding it with another, this intention is not that of genus; it is rather that to which the intellect attributes the intention of genus, as, for instance, to what is signified by the term animal.
We have thus made clear how the essence or nature is related to the notion of species, for the notion of species is not among those that pertain to the essence considered absolutely; nor is it among the accidents that follow from the existence that the essence has outside the soul, as whiteness or blackness. Rather, the notion of species is among the accidents that follow from the existence the essence has in the intellect. And in this way as well do the notions of genus or difference pertain to essences.
