a man can be given only what he can use; and he can use only that for which he has sacrificed something

I have become so accustomed to think "scientifically" that I am afraid even to imagine that there may be something else beyond the outer covering of life. I feel like a man condemned to death, whose companions have been hanged and who has already become reconciled to the thought that the same fate awaits him.

The problem of Eternity, of which the face of the Sphinx speaks, takes us into the realm of the impossible. Even the problem of Time is simple in comparison with the problem of Eternity.

Possibly the most interesting first impression of my life came from the world of dreams.

I've found that the chief difficulty for most people was to realize that they had really heard new things: that is things that they had never heard before. They kept translating what they heard into their habitual language. They had ceased to hope and believe there might be anything new.

A religion contradicting science and a science contradicting religion are equally false.

The number of laws is constantly growing in all countries and, owing to this, what is called crime is very often not a crime at all, for it contains no element of violence or harm.