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

by George Hastings McNair

M — S

S — G

Here, then, are the types that represent all the syllogisms which mediate inference may use. Logic recognizes no other. Since every successful student of logic must be familiar with the four figures, the following may be used as a suggestive aid to reproducing the figures at will:

First. It is easy for any one to remember this syllogism:

All men are mortal,

Socrates is a man,

∴ Socrates is mortal.

In fact, it comes down to us from the time of Aristotle, and is therefore a patriot of many generations to whom the faithful should touch their hats. Let us, then, be ready to reproduce this syllogism with automatic precision, since it will enable us to know at once the position of the terms in the first figure. Second. Converting the terms of the major premise of the first figure gives the second figure, as, e. g.:

First figure.		Second figure.
M — G	(Convert)	G — M
S — M		S — M
S — G		S — G

Third. Converting the terms of the minor premise of the first figure gives the third figure, as, e. g.: