The natural and moral world is the two-fold object of man's rational care.

The study of intelligence must be grounded in the study of symbol systems.

Marxian Socialism must always remain a portent to the historians of Opinion — how a doctrine so illogical and so dull can have exercised so powerful and enduring an influence over the minds of men， and， through them， the events of history.

The past is a foreign country; they do things differently there.

黑暗修复了光明修不了的东西。