The world is all the richer for having a devil in it, so long as we keep our foot upon his neck.

A Beethoven string-quartet is truly, as some one has said, a scraping of horses' tails on cats' bowels, and may be exhaustively described in such terms; but the application of this description in no way precludes the simultaneous applicability of an entirely different description.

The entire routine of our memorized acquisitions, for example, is a consequence of nothing but the Law of Contiguity. The words of a poem, the formulas of trigonometry, the facts of history, the properties of material things, are all known to us as definite systems or groups of objects which cohere in an order fixed by innumerable iterations, and of which any one part reminds us of the others.

Seek out that particular mental attribute which makes you feel most deeply and vitally alive.

Formula to live your dream: 1. Be bold. 2. Begin now, 3. No exceptions.

The ultimate test of what a truth means is the conduct it dictates or inspires.

We never fully grasp the import of any true statement until we have a clear notion of what the opposite untrue statement would be.