Christ . . . said that a man who had looked after a woman lustfully had sinned as much as the man who had seduced her. How absurd!

No great achievement is possible without persistent work.

Machines are worshipped because they are beautiful and valued because they confer power; they are hated because they are hideous and loathed because they impose slavery.

If life is to be fully human it must serve some end which seems, in some sense, outside human life, some end which is impersonal and above mankind, such as God or truth or beauty. Those who best promote life do not have life for their purpose. They aim rather at what seems like a gradual incarnation, a bringing into our human existence of something eternal, something that appears to imagination to live in a heaven remote from strife and failure and the devouring jaws of Time.

To a mind of sufficient intellectual power, the whole of mathematics would appear trivial, as trivial as the statement that a four-footed animal is an animal.

I do not pretend to start with precise questions. I do not think you can start with anything precise. You have to achieve such precision as you can, as you go along.

To be able to concentrate for a considerable time is essential to difficult achievement.