Illicit Minor

Illicit minor is a formal fallacy committed in a categorical syllogism that is invalid because its minor term is undistributed in the minor premise but distributed in the conclusion.

This fallacy has the following argument form:

All A are B.
All A are C.
Therefore, all C are B.

Example:

All cats are felines.
All cats are mammals.
Therefore, all mammals are felines.


The minor term here is mammal, which is not distributed in the minor premise "All cats are mammals," because this premise is only defining a property of possibly some mammals (i.e., that they're cats.) However, in the conclusion "All mammals are felines," mammal is distributed (it is talking about all mammals being felines). It is shown to be false by any mammal that is not a feline; for example, a dog.

Example:

Pie is good.
Pie is unhealthy.
Thus, all good things are unhealthy.


Famous quotes containing the words illicit and/or minor:

    The anger
    that my friends
    planted in my heart
    when they somehow found
    a hole in it
    ran off
    like an illicit lover
    as soon as I saw my man.
    Hla Stavhana (c. 50 A.D.)

    If, for instance, they have heard something from the postman, they attribute it to “a semi-official statement”; if they have fallen into conversation with a stranger at a bar, they can conscientiously describe him as “a source that has hitherto proved unimpeachable.” It is only when the journalist is reporting a whim of his own, and one to which he attaches minor importance, that he defines it as the opinion of “well-informed circles.”
    Evelyn Waugh (1903–1966)