On Logic

CONCERNING Logic, Stuart Mill has said: “I am persuaded that nothing in modern education tends so much, when properly used, to form exact thinkers, who attach a precise meaning to words and propositions and are not imposed on by vague, loose or ambiguous terms. The boasted influence of mathematical studies is nothing to it, for in a mathematical process none of the real difficulties of correct ratiocination occur (mathematical proposition, for example, are but universal affirmatives; furthermore the two terms are united by the sign, hence the immediate possibility of pure and simple conversion, etc.). For want of some such discipline many otherwise able men are altogether incapable of disentangling the intricacies of confused and self-contradictory thought…”

~Quoted in An Introduction to Logic, by Jacques Maritain.

Logic, by Luca della Robbia.
Stone, c. 1437; Museo dell'Opera del Duomo, Florence.