I even got a letter from a young woman in British Columbia that began as follows: 'Today I am eighteen. I am sitting at the window, looking out at the rain, and thinking how much I love you.'

I have never, in all my life, not for one moment, been tempted toward religion of any kind. The fact is that I feel no spiritual void. I have my philosophy of life, which does not include any aspect of the supernatural and which I find totally satisfying. I am, in short, a rationalist and believe only that which reason tells me is so.

There seems to be a feeling that anything that is natural is good. Strychnine is natural.

The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'

In life, people will take you at your own reckoning.

Knowledge is indivisible. When people grow wise in one direction, they are sure to make it easier for themselves to grow wise in other directions as well. On the other hand, when they split up knowledge, concentrate on their own field, and scorn and ignore other fields, they grow less wise - even in their own field.

When I die I won't go to heaven or hell; there will just be nothingness.