Any attempt to shape the world and modify human personality in order to create a self-chosen pattern of life involves many unknown consequences. Human destiny is bound to remain a gamble, because at some unpredictable time and in some unforeseeable manner nature will strike back. The multiplicity of determinants which affect biological systems limits the power of the experimental method to predict their trends and behavior.

Whatever his inhibitions and tastes, Western man believes in the natural holiness of seminudism and raw vegetable juice, because these have become for him symbols of unadultered nature.

Man will survive as a species for one reason: He can adapt to the destructive effects of our power-intoxicated technology and of our ungoverned population growth, to the dirt, pollution and noise of a New York or Tokyo. And that is the tragedy. It is not man the ecological crisis threatens to destroy but the quality of human life.

... men as a rule are more preoccupied with the dangers that threaten their life than interested in the biological forces on which they depend for a constructive existence.

What happens in the mind of man is always reflected in the disease of his body.

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

... 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.