Human destiny is bound to remain a gamble, because at some unpredictable time and in some unforeseeable manner nature will strike back.

Clearly, health and disease cannot be defined merely in terms of anatomical, physiological, or mental attributes. Their real measure is the ability of the individual to function in a manner acceptable to himself and to the group of which he is a part.

The very process of living is a continual interplay between the individual and his environment, often taking the form of a struggle resulting in injury or disease.

Sometimes the more measurable drives out the most important.

As long as mankind is made up of independent individuals with free will, there cannot be any social status quo. Men will develop new urges, and these will give rise to new problems, which will require ever new solutions. Human life implies adventure, and there is no adventure without struggles and dangers.

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.

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.