It is not man the ecological crisis threatens to destroy but the quality of human life.

In man, at least, satisfaction is commonly followed by boredom.

... each type of civilization has had diseases peculiar to it and at each period the various social groups in any community also have differed in this regard.

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

Man not only survives and functions in his environment, he shapes it and he is shaped by it.

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.

With reference to life there is not one nature; there are only associations of states and circumstances, varying from place to place and from time to time.