In my last post I promised to explain the reasoning behind the rules of validity that relate to the distribution of terms. Recall that a term is distributed in a statement when it refers to the entire extension of the term. This implies, as we saw, that the subjects of universal statements and the predicates of negative statements are distributed.

One related rule of validity says this:

A valid syllogism must distribute in its premise any term distributed in the conclusion.

This syllogism, for example, breaks this rule: Continue reading Illicit terms →