Science can teach us, and I think our hearts can teach us, no longer to look around for imaginary supporters, no longer to invent allies in the sky, but rather to look to our own efforts here below to make the world a fit place to live.

Nothing can penetrate the loneliness of the human heart except the highest intensity of the sort of love the religious teachers have preached.

The idea that things must have a beginning is really due to the poverty of our imagination.

A strange mystery it is that Nature, omnipotent but blind, in the revolutions of her secular hurryings through the abysses of space, has brought forth at last a child subject still to her power but gifted with sight, with knowledge of good and evil, with the capacity of judging all the works of his unthinking mother.

It is possible that mankind is on the threshold of a golden age; but, if so,it will be necessary first to slay the dragon that gaurds the door,and this dragon is religion

I am myself a dissenter from all known religions, and I hope that every kind of religious belief will die out.

Every living thing is a sort of imperialist, seeking to transform as much as possible of its environment into itself.

There is no logical impossibility in the hypothesis that the world sprang into being five minutes ago, exactly as it then was, with a population that "remembered" a wholly unreal past. There is no logically necessary connection between events at different times; therefore nothing that is happening now or will happen in the future can disprove the hypothesis that the world began five minutes ago.

What makes a free thinker is not his beliefs, but the way in which he holds them. If he holds them because his elders told him they were true when he was young, or if he holds them because if he did not he would be unhappy, his thought is not free; but if he holds them because, after careful thought, he finds a balance in their favor, then his thought is free, however odd his conclusions may seem.