There are four classes of Idols which beset men's minds. To these for distinction's sake I have assigned names — calling the first class, Idols of the Tribe; the second, Idols of the Cave; the third, Idols of the Market-Place; the fourth, Idols of the Theater.

It is not possible to run a course aright when the goal itself has not been rightly placed.

Truth will sooner come out from error than from confusion.