Page:Popular Science Monthly Volume 71.djvu/83

Rh rightly departing from the rough and ready practise which calls almost anything natural selection, have wrongly gone on to find about as many different forms of selection as there are social institutions and customs.

As regards the scope of selection in general in its application to man, we are now prepared to believe that any influence that bears in any of the four ways enumerated upon the continuance of lines of descent presumably has selective importance. Only on the hypothesis of pure chance distribution of effects can any influence known to affect propagation be declared to be non-selective. The chances against this are infinity to one. No enumeration can cover all possible selective agencies. Every habit, custom and institution of man might well be examined with a view to detecting such effects. Selection must have tremendous importance in human society. It certainly is a central problem, perhaps the fundamental problem and point of departure, for a science of society.

Only the confounding of selection in general with mere lethal selection can explain the opinion that selection is inoperative in human society. Even so, the opinion is not well-considered, for there is much selection by death in civilized man. Lethal selection is not a matter of violent death, or death in struggle. The conception of natural selection as the result of a "free fight"—a bellum omnium contra omnes—has no Justification in any phase of its application. Half the population of many civilized societies, and of course on the whole the weaker half, dies before reaching maturity. In the parts of the United States for which tolerable registration statistics are to be had, at least one third of the deaths are of persons under the age of fifteen. This involves lethal selection.

But lethal selection is not all. The forms and agencies of selection multiply as we pass upwards in the organic series. Hence we might expect a culmination, as regards manifoldness and complexity, in man. It is true that there are fewer births to select from, but the selection may come before birth, and in fact comes so always in the last analysis. And if there is less selection by death in man, there is also less random and indiscriminate destruction of human than of lower animal or plant life. The field for the study of selection in human society is as great and as complex as that in which the biologist works.

Of lethal selection in its application to man, little more need be said. Life-tables and deaths according to age tell the story. Lethal selection is not to be dismissed with the statement that men no longer habitually attack and kill one another, and in civilized states do not die for want of food. Of course selection by the dissolution of the weaker constitutions relates chiefly to physical qualities, but its