Marvellous, what ideas the young people have these days. But I don't believe a word of it.

You can never solve a problem with the same kind of thinking that created the problem in the first place.

Smoke like a chimney, work like a horse, eat without thinking, go for a walk only in really pleasant company.

... knowledge must continually be renewed by ceaseless effort, if it is not to be lost. It resembles a statue of marble which stands in the desert and is continually threatened with burial by the shifting sand. The hands of service must ever be at work, in order that the marble continue to lastingly shine in the sun. To these serving hands mine shall also belong.

I never thought that others would take my theories so much more seriously than I did.

The really valuable method of thought to arrive at a logically coherent system is intuition.

I have survived two wars, two wives and Hitler.