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

Few minds wear out; more rust out. – Christian N. Bovee

No amount of energy will take the place of thought. A strenuous life with its eyes shut is a kind of wild insanity. – Henry Van Dyke

Men who borrow their opinions can never repay their debts. – George Savile, Marquess de Halifax, Miscellaneous Thoughts and Reflections