Social evolution may be the result of intention, but it rarely, if ever, produces the result intended.

Nature always strikes back. It takes all the running we can do to remain in the same place.

The mechanisms of vis medicatrix naturæ—the most healing power of nature—are so effective that most diseases are self-terminating.

As far as life is concerned, there is no such thing as "Nature". There are only homes. Home is that environment to which the individual has become adapted; and almost everything is unnatural outside his range of adaptation. Harmonious equilibrium with nature is an abstract concept with a Platonic beauty but lacking the flesh and blood of life. It fails, in particular, to convey the creative emergent quality of human existence.

One may wonder indeed whether the pretense of superior health is not itself rapidly becoming a mental aberration.

Man could escape danger only by renouncing adventure, by abandoning that which has given to the human condition its unique character and genius among the rest of living things.

There is an unbroken continuum from the wisdom of the body to the wisdom of the mind, from the wisdom of the individual to the wisdom of the race.