Quintilian, Institutio Oratoria, Book 5
Harold Edgeworth Butler, Ed.

[82] As examples of necessary conclusions on the other hand I may cite the following: “If wisdom makes a man good, a good man must needs be wise”; and again, “It is the part of a good man to act honourably, of a bad man to act dishonourably,” or “Those who act honourably are considered good, those who act dishonourably are considered bad men.” In these cases the conclusion is correct. On the other hand, “though exercise generally makes the body robust, not everyone who is robust is given to exercise, nor is everyone that is addicted to exercise robust. Nor again, because courage prevents our fearing death, is every man who has no fear of death to be regarded as a brave man; nor is the sun useless to man because it sometimes gives him a headache.”