Universa Philosophia

In every proposition, whether spoken or written, three words or expressions are found, to which three acts in the intellect correspond. In this proposition, Peter is white, the first word is called the subject, the third the predicate, and the second the union or copula. The whole essence of a proposition consists in these, just as the essence of a human being consists in body, soul, and their union. The same number of words occurs in every proposition made with other verbs, as in Peter runs: for this has the sense, Peter is running.

The subject is that of which we say or predicate something, as in the proposition Peter is white: Peter is the subject, because of him it is said and predicated that he is white. The predicate, in turn, is the thing that is said or predicated of another; thus white is predicated and said of Peter in that proposition. Subject is so called from subiicio, that is, “it is thrown beneath another.” For just as, among physical things, Peter is a subject because he lies beneath accidents, while the accidents are in Peter, so logically the subject is what underlies predication, which places the predicate in it. The predicate, however, is so called because it is the thing predicated. The union is so called because it unites or joins the subject to the predicate. For it signifies that the subject and predicate are the same, which is to unite them. In a negative proposition, however, it does not unite but separates the predicate from the subject and denies that they are the same, as in Peter is not a stone.

Predicate and subject are one thing as that which, and another as that by which. That which is the thing itself, or the object that is subjected or predicated. That by which is the word, writing, or concept by which we say one thing of another. For example, in Peter is a human being, what I say and affirm of Peter is the human being himself, who really exists in Peter; he is the predicate that which, or the matter that is predicated. But the word human being is the instrument by which I say Peter is a human being; it is the predicate that by which, that is, the formal character by which I predicate “human being.” In this sense the Nominalists say that one word is predicated of another, not as that which—for that would be false, since Peter is a human being would be false if it meant that the word Peter is the word human being—but as that by which. That is, it is predicated in the character of a sign taken for the thing signified. For it amounts to saying that the word human being is predicated that by which of the word Peter to say that the word human being is a sign of the same thing of which the word Peter is a sign. The reason is that a sign is taken for the thing signified, and thus stands in place not of itself but of the thing it signifies. For example, someone sees two images of Pompey and says, This is Pompey; the same Pompey, or the same man, is here and there—not because those images are the same or are Pompey, but because they are taken for their prototype, whose images they are. But if he sees a statue of Caesar and compares it with a statue of Pompey, he says, This is not Pompey, that is, it does not represent Pompey. I shall show elsewhere from Ockham that this is the Nominalists’ meaning. All dialecticians speak in this way when they teach rules about propositions, yet they wrongly accuse the Nominalists of it.

From § 1, conclude that it matters little whether the subject or the union is the first or second word of a proposition. For it is not the subject because it is first, nor the union because it is in the middle; rather, it is the subject because something is said of it, and the union because it joins and states that the predicate is the same as the subject. For in the proposition Peter is white, the subject, predicate, and union are the same as in Is Peter white or White Peter is.