Faith: a firm belief for which there is no evidence.

When we perceive any object of a familiar kind, much of what appears subjectively to be immediately given is really derived from past experience.

Science, in its ultimate ideal, consists of a set of propositions arranged in a hierarchy, the lowest level of the hierarchy being concerned with particular facts, and the highest with some general law, governing everything in the universe. The various levels in the hierarchy have a two-fold logical connection, travelling one up, one down; the upward connection proceeds by induction, the downward by deduction.

As I grew up I became increasingly interested in philosophy, or which [his family] profoundly disapproved. Everytime the subject came up they repeated with unfailing regularity, "What is mind? No matter. What is matter? Never mind." After some fifty or sixty repititions, this remark ceased to amuse me.

There is an element of the busybody in our conception of virtue: unless a man makes himself a nuisance to a great many people, we do not think he can be an exceptionally good man.

Dora and I are now married, but just as happy as we were before.

Do not fear to be eccentric in opinion, for every opinion now accepted was once eccentric.