A Class Room Logic / Deductive and Inductive, with Special Application to the Science and Art of Teaching

by George Hastings McNair

Regressive

All A is B   A biped is an animal,

All C is A   A man is a biped,

All D is C   A teacher is a man,

All E is D   Thomas Arnold was a teacher,

Hence all E is B   Hence Thomas Arnold was an animal.

When regarded from the viewpoint of extension, the progressive sorites proceeds from the smaller to the larger while the regressive is the converse of this. The point may be illustrated by circles:

FIG. 15.

Circle 1 stands for Thomas Arnold.