Religions that teach brotherly love have been used as an excuse for persecution, and our profoundest scientific insight is made into a means of mass destruction.

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.

Remote from human passions, remote even from the pitiful facts of nature, the generations have gradually created an ordered cosmos [mathematics], where pure thought can dwell in its natural home.

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

Cruel men believe in a cruel god and use their belief to excuse their cruelty. Only kindly men believe in a kindly god, and they would be kindly in any case.

Aristotle maintained that women have fewer teeth than men; although he was twice married, it never occurred to him to verify this statement by examining his wives' mouths.

Curious learning not only makes unpleasant things less unpleasant but also makes pleasant things more pleasant.