All exact science is dominated by the idea of approximation.

I cannot favour laws such as that of Idaho, which allows sterilization of 'mental defectives, epileptics, habitual criminals, moral degenerates, and sex perverts.' The last two categories here are very vague . . . The law of Idaho would have justified the sterilization of Socrates, Plato, Julius Caesar, and St. Paul.

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.

A stupid man's report of what a clever man says can never be accurate, because he unconsciously translates what he hears into something he can understand.

To discover a system for the avoidance of war is a vital need of our civilisation.

In detective stories . . . I alternately identify myself with the murderer and the huntsman-detective, but . . . there are those to which this vicarious outlet is too mild.

Philosophy is an unusually ingenious attempt to think fallaciously.