That the world is in a bad shape is undeniable, but there is not the faintest reason in history to suppose that Christianity offers a way out.

From India to Spain, the brilliant civilization of Islam flourished. What was lost to christendom at this time was not lost to civilization, but quite the contrary.

There are three ways of securing a society that shall be stable as regards population. The first is that of birth control, the second that of infanticide or really destructive wars, and the third that of general misery except for a powerful minority.

But I simply can't stand a view limited to this earth, I feel life is so small unless it has windows into other worlds...I like mathematics largely because it is not human.

Dogmatism is the greatest of mental obstacles to human happiness.

Man is a rational animal – so at least I have been told. Throughout a long life, I have looked diligently for evidence in favour of this statement, but so far I have not had the good fortune to come across it, though I have searched in many countries spread over three continents.

When you are studying any matter or considering any philosophy, ask yourself only: what are the facts, and what is the truth that the facts bear out. Never let yourself be diverted by what you wish to believe, but look only and surely at what are the facts.