Aristotle on Logic and Metaphysics

1. Aristotle on Logic and Metaphysics

2. LOGIC • Syllogism: “discourse in which certain things being stated, something other than what is stated follows of necessity from their being so” (Anal. Priora, I.1.24b). • A syllogism contains two premises and a conclusion. If two propositions are to have any hope of yielding a conclusion, they must have a common term, called the ‘middle term’ (M), and the terms of the conclusion will be the other two of the three terms contained in the premises.

3. Three Forms of Syllogism • The Middle Term is Subject in one premise and Predicate in the other. Thus: M is P, S is M, therefore S is P. Every human being is mortal. Socrates is a human being. Therefore Socrates is mortal. • The Middle Term is Predicate in both premises. P is M, S is not M, therefore S is not P. Birds can fly. But no cats can fly. Therefore, no cats are birds. • The Middle Term is Subject in both premises. Thus: M is P, M is S, therefore, S is P. Birds can fly. But birds are animals. Therefore, some animals can fly.

4. The Categories • A substance is “that which is neither said of a subject nor in a subject.” For example, the individual person or the individual horse. The species to which these substances belong (and also the genus) is called secondary substances (e.g. humanity and animal). • All the other things are either predicable of the primary substances as subjects or in them as subjects.

5. METAPHYSICS The opening of the Metaphysics: “All human beings by nature desire to know.”

6. Degrees of Knowledge • The person of mere experience may know that a certain medicine had done good to X when he was ill, but without knowing the reason for this. • The person of art knows the reason. Art aims at production of some kind. • Wisdom does not aim at producing anything or securing some effect – it is not utilitarian -- but at apprehending the first principles of Reality, i.e. at knowledge for its own sake  the highest science.

7. Four Causes • Material cause: that out of which a thing comes to be and which persists. • Formal cause: the form or the archetype, i.e. the definition of the essence and its genera. • Efficient or moving cause: the primary source of the change or rest. • Final cause: the end or that for the sake of which a thing is done.

8. Substance • The individual substance is a compound of the subject or substratum and the essence of form. To the individual substance belong the conditions and the relations, which are distinguished according to the nine accidental categories (quantity, quality, relation, etc.).

9. Change • Changes: the actualization of a potentiality. There must be a substratum of change, for in every case of change which we observe there is something that changes. • Actuality is prior to potency. The actual is always produced from the potential; the potential is always reduced to act by the actual, that which is already in act, as a human being is produced by a human being.

10. God • That which is eternal is prior in substance to that which is perishable; and that which is eternal, imperishable, is in the highest sense actual. God is the First Unmoved Mover, immaterial, the source of all movement. • God moves the universe as Final Cause, as being the object of desire. • God is “Thought of Thought,” which eternally thinks itself.

11. Significance • Critique of Plato: The Forms contain the essence and inner reality of sensible objects; but how can objects that exist apart from the sensibles contain the essence of those sensibles? (Metaph. 991b1-3). • The Forms are not “up there” but rather down here in the individuals.