We need to make a world in which fewer children are born, and in which we take better care of them.

All attempts to adapt our ethical code to our situation in the technological age have failed.

I believe there is no philosophical high-road in science, with epistemological signposts. No, we are in a jungle and find our way by trial and error, building our road behind us as we proceed.

The belief in a single truth is the root cause for all evil in the world.

It is odd to think that there is a word for something which, strictly speaking, does not exist, namely, "rest." We distinguish between living and dead matter; between moving bodies and bodies at rest. This is a primitive point of view. What seems dead, a stone or the proverbial "door-nail," say, is actually forever in motion. We have merely become accustomed to judge by outward appearances; by the deceptive impressions we get through our senses.

There are two objectionable types of believers: those who believe the incredible and those who believe that 'belief' must be discarded and replaced by 'the scientific method.

To present a scientific subject in an attractive and stimulating manner is an artistic task, similar to that of a novelist or even a dramatic writer. The same holds for writing textbooks.