Nature has no use for the plea that one 'did not know'.

The fact is that certain ideas exist almost everywhere and at all times and can even spontaneously create themselves quite independently of migration and tradition.

I've realized that somebody who's tired and needs a rest, and goes on working all the same is a fool.

The individual disposition is already a factor in childhood; it is innate, and not acquired in the course of a life.

I had always been impressed by the fact that there are surprisingly many individuals who never use their minds if they can avoid it, and yet are not stupid, and an equal number who obviously do use their minds but in an amazingly stupid way.

All the works of man have their origin in creative fantasy. What right have we then to depreciate imagination.

Nature does not deceive or conceal, but reveals.