Deductive LogicTopic #4 of 10

Syllogisms

Classical form of deductive argument consisting of a major premise, minor premise, and conclusion.

A syllogism is a standard form logic argument with two premises and a conclusion.

Categorical Syllogisms

Deal with categories of things using "All", "No", or "Some".

  • All S are P (Universal Affirmative)
  • No S are P (Universal Negative)
  • Some S are P (Particular Affirmative)
  • Some S are not P (Particular Negative)

Venn Diagrams

Venn diagrams are often used to test the validity of Categorical Syllogisms.

All M are P. All S are M. Therefore, All S are P. (Barbara Form - Valid)

Hypothetical Syllogisms

Based on "If... then..." statements.

If P, then Q. If Q, then R. Therefore, If P, then R. (Chain Reaction)