From Human Action,
"One of the privileges which society affords to the individual is the privilege of living in spite of sickness or physical disability. Sick animals are doomed. Their weakness handicaps them in their attempts to find food and to repel aggression on the part of other animals. Deaf, nearsighted, or crippled savages must perish. But such defects do not deprive a man of the opportunity to adjust himself to life in society. The majority of our contemporaries are afflicted with some bodily deficiencies which biology considers pathological. Our civilization is to a great extent the achievement of such men. The eliminative forces of natural selection are greatly reduced under social conditions. Hence some people say that civilization tends to deteriorate the hereditary qualities of the members of society.
Such judgments are reasonable if one looks at mankind with the eyes of a breeder intent upon raising a race of men equipped with certain qualities. But society is not a stud-farm operated for the production of a definite type of men. There is no "natural" standard to establish what is desirable and what is undesirable in the biological evolution of man. Any standard chosen is arbitrary, purely subjective, in short a judgment of value. The terms racial improvement and racial degeneration are meaningless when not based on definite plans for the future of mankind.
It is true, civilized man is adjusted to life in society and not to that of a hunter in virgin forests."