Shall we now be told that all this reasoning is purely subjective and that an objective reality is beyond our ken? Let St. Thomas answer: "The quiddity of a thing is properly the object of the intellect. Wherefore, as the senses are always true in relation to their own proper sensible objects (for a sensile judgment is a natural act of a sense, and 'nature never fails in things necessary'); so is the intellect, likewise, in its cognition of essence, as Aristotle says in the third book De anima. But accidentally it may chance to be false; that is to say, inasmuch as the intellect conjoins or separates falsely. This takes place in two ways: either by its attributing the definition of one thing to another, as if it should conceive, for instance, 'rational animal' to be the definition of an 'ass'; or, by joining together members in a definition, which do not admit of such conjunction; as, for instance, if it should conceive 'immortal irrational animal' to be the definition of an 'ass.' For it is false to say, 'Some irrational animals are immortal.' Hence it is plain that a definition cannot be false, except as involving a false affirmation. . . . In like manner, the intellect is not in any way subject to deception as to first principles. Wherefore, it is evident that, if intellect is taken to mean that action whence it derives its name, falsity is not in the intellect" (De verit., q. I, a. 12). And, again, in the Summa theologica (I, q. 17, a. 1) he says, "Because it is in our nature to judge of entities by their external phenomena (since our cognition takes its beginning from the senses, which primarily and absolutely have for object external accidents); hence it arises that those entities which, in their sensile accidents have a similarity to other entities, are called false in respect of these other entities. . . . Accordingly, the Pseudo-Augustine says in the second book of his Soliloquies, that 'we call things false, which we apprehend as verisimilitudes.'"
Our faculties are then naturally veracious, and we are only sketching in other words the Thomistic accounting for human knowledge when we say with Dr. McCosh: "This knowledge is, at first, only of individual things,—of things in the concrete as they present themselves. But out of this it (the intellect)
