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- Oct 6, 2014
Kant said:Being is evidently not a real predicate, that is, a concept of something that can be added to the concept of a thing It is merely the positing of a thing, and of certain determinations in themselves. Logically, it is merely the copula of a judgment.
The Critique of Pure Reason, A 599/B 627
Thought is the interconnection of concepts which are thereby identified with each other; judgment is the act of combining the concepts. We call a concept that is connected to another concept by means of judgment the predicate to the latter's subject. For example, in the sentence,Schopenhauer said:It seems to me that the doctrine of the laws of thought might be simplified if we were only to set up two, the law of excluded middle and that of sufficient reason. The former thus: “Every predicate can either be affirmed or denied of every subject.” Here it is already contained in the “either, or” that both cannot occur at once, and consequently just what is expressed by the laws of identity and contradiction.
The second law of thought, the principle of sufficient reason, would affirm that the above attributing or denying must be determined by something different from the judgment itself, which may be a (pure or empirical) perception, or merely another judgment.
The World as Will and Representation, Vol. II, 286
Socrates is the subject, 'a man' the predicate. 'is', as a conjugation of 'being', is, as Kant said, the copula, which is no part of the subject nor the predicate. The common classroom conception of the sentence as a thing composed of only a subject and a predicate does not adequately express the function of the word 'being'. It refers not to a concept which can be predicated of another, but to the predication itself.Socrates is a man.
Every subject is a predicate to its own predicate's subject—that is, identity is a symmetrical relation
—but not all concepts are not identical with all other concepts. For example, Socrates and Immanuel Kant are both men, but Socrates is not Immanuel Kant.
We say that a concept which is identical to concepts which are not identical to each other contains those concepts
and may in turn be contained by yet another concept.
My examples have thus far shown only the containment of the particular by the general, but the general is also contained by the particular. Just as each species incorporates many individuals, so does each individual partake in many species.
There are thus two senses in which non-identical concepts can be predicated of another:
- As reifications of an idea; or
- As attributes of a substance
The answer, then, to @onesteptwostep's question is that Plato's ideas don't exist and neither does substance because existence is not a predicate. As for what they are in concreto, my view is that idea and substance are alternative names for the totality of the objects of experience and the unity of the percipient subject respectively.
What do you think?