Illicit Minor

Alias: Illicit Process of the Minor Term

Type: Illicit Process


Any form of categorical syllogism in which the minor term is distributed in the conclusion but not in the minor premiss.

Example Counter-Example
All terrorists are extremists.
All extremists are radicals.
Therefore, all radicals are terrorists.
All whales are mammals.
All mammals are animals.
Therefore, all animals are whales.
Venn diagram

Venn Diagram:

This diagram represents both the Example and Counter-Example. It does not show the conclusion, "All S is P", to be true, which shows that both arguments are invalid.


"Illicit minor" does not refer to underage drinking, but to an illicit process—that is, distribution—of the minor term in a categorical syllogism.

Sibling Fallacy: Illicit Major


Irving Copi & Carl Cohen, Introduction to Logic (Tenth Edition) (Prentice Hall, 1998), p. 277.