Page:Popular Science Monthly Volume 71.djvu/88

82 forms of selection for the study of man and his social evolution. An extended treatment of this subject is one of the great desiderata of the science of sociology, the half of which will be the theory of selection in its application to man.

A logical and seemingly very forcible objection to the idea that selection applies to man is contained in the contention that heredity has nothing to do with the higher, which are the distinctively human, qualities in human nature. But the common-sense and practical view id that even the highest intellectual and moral qualities are to some extent inheritable. Men look for family traits not merely in the physical features of children. There is certainly a tendency to the inheritance of insanity, which shows that mind is subject to heredity. It is enough for the purposes of the sociologist if the inheritance of the properly human qualities be only statistically true, that is, true for the mass, though not true of every individual. In fact, this is what we should expect. For a number of reasons variation should be at its best in characteristics distinctively human. Biologically viewed, man is like a domestic animal and is a dominant species, both of which facts imply great variability. There is also approximately unrestricted crossing in mankind. The environment, that is complex civilized society, demands diverse specialized qualities; so that the external conditions favor multilinear evolution. The distinctively human qualities have been latest acquired and are therefore most subject to variation. In man, moreover, as the most socialized of animals, much may be left to imitation and education, that is, to "social heredity," Hence there is less need of a hard and fast physical heredity.

The fact that the line of least resistance in development is the resultant of two sets of forces, internal (variation and heredity) and environmental (selection), must not be allowed for an instant to slip the mind. The interdependence and delicacy of adjustment between these forces increases with the complexity of man's higher, special characteristics. Hence the apparent decrease in the importance of heredity. The distinction between what is innate and what is acquired often hinges on mere ease of enumeration of cases of apparent predominance, or relative independence, of one or the other factor. Or the results are referred to the least easily assumed to be constant factor. Such is in practise man's application of causation. Both sorts of factors are always necessarily operative. It must be granted that proper inheritance is a necessary precondition to the appearance of noble qualities, and this alone concedes the presence and importance of heredity. Both internal constitution and modifications from without are determinants of development and man can no more get along without the right sort of heredity now than ever. Complexity and lack of fixity in development do not remove from the sphere of heredity, though they do mean greater possibilities and greater likelihood