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chapters 10-13

Reasoning

the act by which the mind requires new knowledge by means of what it already knows

the two kinds of reasoning

deductive and inductive

Deductive inference

the act by which the mind establishes a connection between the antecedent and the consequent.

Syllogism

a group of propositions in orderly sequence, one of which (the consequent) is said to be necessarily inferred from the others (the antecedent).

Essential Law of Argumentation

If the antecedent is true, the consequent must also be true.

First Corollary

If the syllogism is valid and the consequent is false, then the antecedent must be false.

Second Corollary

In a valid syllogism with a true consequent, the antecedent is not necessarily true.

Syllogism Terms

major, minor, middle

Major Term

the predicate of the conclusion

Minor Term

The subject of the conclusion

Middle Term

The term that appears in both premises, but not in the conclusion

Major Premise

The premise which contains the major term

Minor Premise

The premise which contains the minor term

The Principle of Reciprocal Identity

Two terms that are identical with a third term are identical to each other.

The Principle of Reciprocal Non-Identity

Two terms, one of which is identical with a third term and the other of which is nonidentical with that third term, are nonidentical to each other.

The Dictum de Omni

What is affirmed universally of a certain term is affirmed of every term that comes under that term

The Dictum de Nullo

What is denied universally of a certain term is denied of every term that comes under that term.

The 3 catagories of the 7 rules of catagorical syllogisms

Terminological, Quantitative, Qualitative

Terminological Rules

I. Ther must be three and only three terms. II.The middle term must not occur in the conclusion

Quantitative Rules

III. If a term is distributed in the conclusion, then it must be distributed in the premise. IV. The middle term must be distributed at least once.

Qualitative Rules

V. No conclusion can follow from two negative premises. VI. I the two premises are affirmative, the conclusion must also be affirmative. VII. If either premise is negative, the conculsion must be negative.

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