I say quite deliberately that the Christian religion, as organized in its Churches, has been and still is the principal enemy of moral progress in the world.

There are infinite possibilities of error, and more cranks take up fashionable untruths than unfashionable truths.

If I were a medical man, I should prescribe a holiday to any patient who considered his work important.

It is false to suggest that men must turn away from his desires in the interest of a higher duty. Men only responds to duty if he desires to do so. To understand men, you must understand their desires and the relative strength of those desires.

The pleasure of work is open to anyone who can develop some specialised skill, provided that he can get satisfaction from the exercise of his skill without demanding universal applause.

Very many people spend money in ways quite different from those that their natural tastes would enjoin, merely because the respect of their neighbors depends upon their possession of a good car and their ability to give good dinners. As a matter of fact, any man who can obviously afford a car but genuinely prefers travels or a good library will in the end be much more respected than if he behaved exactly like everyone else.

Physics is mathematical not because we know so much about the physical world, but because we know so little; it is only its mathematical properties that we can discover.