Empirical sciences prosecuted purely for their own sake, and without philosophic tendency are like a face without eyes.

Opinion is like a pendulum and obeys the same law. If it goes past the centre of gravity on one side, it must go a like distance on the other; and it is only after a certain time that it finds the true point at which it can remain at rest.

Man is never happy, but spends his whole life in striving after something which he thinks will make him so.

A man of business will often deceive you without the slightest scruple, but he will absolutely refuse to commit a theft.

I observed once to Goethe that when a friend is with us we do not think the same of him as when he is away. He replied, "Yes! because the absent friend is yourself, and he exists only in your head; whereas the friend who is present has an individuality of his own, and moves according to laws of his own, which cannot always be in accordance with those which you form for yourself.

Reading is merely a surrogate for thinking for yourself; it means letting someone else direct your thoughts. Many books, moreover, serve merely to show how many ways there are of being wrong, and how far astray you yourself would go if you followed their guidance. You should read only when your own thoughts dry up, which will of course happen frequently enough even to the best heads; but to banish your own thoughts so as to take up a book is a sin against the holy ghost; it is like deserting untrammeled nature to look at a herbarium or engravings of landscapes.

A man of talent will strive for money and reputation; but the spring that moves genius to the production of its works is not as easy to name