Most of the vices and mortal sins condemned today correspond to inclinations that were purely adaptive or at least harmless in primitive man

Truth in science can be defined as the working hypothesis best suited to open the way to the next better one.

...he who has seen the intimate beauty of nature cannot tear himself away from it again. He must become either a poet or a naturalist and, if his eyes are keen and his powers of observation sharp enough, he may well become both.

The instinctive need to be the member of a closely knit group fighting for common ideals may grow so strong that it becomes inessential what these ideals are.

Every man gets a narrower and narrower field of knowledge in which he must be an expert in order to compete with other people. The specialist knows more and more about less and less and finally knows everything about nothing.

Man has been driven out of the paradise in which he could trust his instincts.

It ought to be realized by all dog owners that obesity shortens a dog's life quite considerably, a life which is much too short anyhow.