Thinking in its lower grades is comparable to paper money, and in its higher forms it is a kind of poetry. – Havelock Ellis, The Dance of Life, 1923

A sect or party is an elegant incognito devised to save a man from the vexation of thinking. – Ralph Waldo Emerson

The thoughts that come often unsought, and, as it were, drop into the mind, are commonly the most valuable of any we have. – John Locke, 16 May 1699

One cannot think crooked and walk straight. – Author Unknown