I have never yet met a healthy person who worried very much about his health, or a really good person who worried much about his own soul.

Quantitative work shows clearly that natural selection is a reality, and that, among other things, it selects Mendelian genes, which are known to be distributed at random through wild populations, and to follow the laws of chance in their distribution to offspring. In other words, they are an agency producing variation of the kind which Darwin postulated as the raw material on which selection acts.

Teleology is like a mistress to a biologist: he cannot live without her but he's unwilling to be seen with her in public.

The advance of scientific knowledge does not seem to make either our universe or our inner life in it any less mysterious.

I will jump into the river to save two brothers or eight cousins.

I think, however, that so long as our present economic and national systems continue, scientific research has little to fear.

The wise man regulates his conduct by the theories both of religion and science. But he regards these theories not as statements of ultimate fact but as art-forms.