Nature's stern discipline enjoins mutual help at least as often as warfare. The fittest may also be the gentlest.

No evidence is powerful enough to force acceptance of a conclusion that is emotionally distasteful.

An accident, a random change, in any delicate mechanism can hardly be expected to improve it. Poking a stick into the machinery of one's watch or one's radio set will seldom make it work better.

No known human group... simply throw out its dead without any ritual or ceremony. In stark contrast, no animal practices burial of dead individuals of its own species.

Marxists are more right than wrong when they argue that the problems scientists take up,. the way they go about solving them, and even the solutions they arc inclined to accept, arc conditioned by the intellectual, social, and economic environments in which they live and work.

Seen in the light of evolution, biology is, perhaps, intellectually the most satisfying and inspiring science. Without that light it becomes a pile of sundry facts -- some of them interesting or curious but making no meaningful picture as a whole.

The living world is not a single array... connected by unbroken series of intergrades.