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

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.

The business of proving evolution has reached a stage when it is futile for biologists to work merely to discover more and more evidence of evolution. Those who choose to believe that God created every biological species separately in the state we observe them, but made them in a way calculated to lead us to the conclusion that they are the products of an evolutionary development are obviously not open to argument. All that can be said is that their belief is an implicit blasphemy, for it imputes to God an appalling deviousness.

Nothing in biology makes sense except in the light of evolution.

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.

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

Man is the only living being who has a developed self-awareness and death-awareness.