In attempting to understand the elements out of which mental phenomena are compounded, it is of the greatest importance to remember that from the protozoa to man there is nowhere a very wide gap either in structure or in behaviour. From this fact it is a highly probable inference that there is also nowhere a very wide mental gap.

No man treats a motorcar as foolishly as he treats another human being. When the car will not go, he does not attribute its annoying behavior to sin; he does not say, 'You are a wicked motorcar, and I shall not give you any more petrol until you go.' He attempts to find out what is wrong and to set it right.

The luxury to disparage freedom is the privilege of those who already possess it.

The first dogma which I came to disbelieve was that of free will. It seemed to me that all notions of matter were determined by the laws of dynamics and could not therefore be influenced by human wills.

To the primitive mind, everything is either friendly or hostile; but experience has shown that friendliness and hostility are not the conceptions by which the world is to be understood.

No satisfaction based upon self-deception is solid.

I do not believe that I am now dreaming, but I cannot prove that I am not.