No great achievement is possible without persistent work.

At the age of eleven, I began Euclid, with my brother as my tutor. ... I had not imagined that there was anything so delicious in the world. After I had learned the fifth proposition, my brother told me that it was generally considered difficult, but I had found no difficulty whatsoever. This was the first time it had dawned on me that I might have some intelligence.

Physics, owing to the simplicity of its subject matter, has reached a higher state of development than any other science.

Religion is something left over from the infancy of our intelligence, it will fade away as we adopt reason and science as our guidelines.

Drunkeness is temporary suicide: the happiness that it brings is merely negative, a momentary cessation of unhappiness.

The puritanism of Christianity has played havoc with the moderation that an enlightened and tolerant critical spirit would have produced. I've noticed that in whatever country, county, town, or other region there is a regulation enjoining temperance, the population seems to be entirely composed of teetotallers and drunkards. There's a Bible on that shelf there. But I keep it next to Voltaire - poison and antidote.

The whole conception of a God is a conception derived from the ancient oriental despotisms. It is a conception quite unworthy of free men. We ought to stand up and look the world frankly in the face. We ought to make the best we can of the world, and if it is not so good as we wish, after all it will still be better than what these others have made of it in all these ages.