I would never die for my beliefs because I might be wrong.

For a good notation has a subtlety and suggestiveness which at times make it seem almost like a live teacher.

I have found, for example, that if I have to write upon sum rather difficult topic, the best plan is to think about it with very great intensity-the greatest intensity of which I am capable-for a few hours or days, and at the end of that time give orders, so to speak (to my subconscious mind) that the work is to proceed underground. After some months I return consciously to the topic and find that the work has been done.

Order, unity, and continuity are human inventions, just as truly as catalogues and encyclopedias.

The time you enjoy wasting is not wasted time.

Although this may seem a paradox, all exact science is based on the idea of approximation. If a man tells you he knows a thing exactly, then you can be safe in inferring that you are speaking to an inexact man.

We are ... led to a somewhat vague distinction between what we may call "hard" data and "soft" data. This distinction is a matter of degree, and must not be pressed; but if not taken too seriously it may help to make the situation clear. I mean by "hard" data those which resist the solvent influence of critical reflection, and by "soft" data those which, under the operation of this process, become to our minds more or less doubtful.