I. We may begin with the frequently noted fact that natural selection—formulated by Darwin as "the preservation of favorable individual differences and variations and the destruction of those that are injurious"—was a conception borrowed from the sphere of human purposeful activity and transferred to the biological realm, in which it has acquired more or less precise connotation. It was a metaphor in the beginning, and now, if it be applied to human conduct, it must lose something of the significance acquired in the biological field. Natural selection must, for example, apply to habits as well as to structural variations. We are not concerned, however, with the legitimacy of its application from the biological but rather from the ethical viewpoint, and particularly with the misconceptions which here beset it.
Now in the very precision with which physical science fixes its concepts is involved a danger, especially when a concept, fixed only within a limited field, is attended by a cloud of other ideas—in this case, 'nature,' 'struggle,' 'environment,' 'life,' etc., which can hardly be used without lurking metaphysical reference. The very term 'natural,' rather than 'biological selection,'[1] proper sixty years ago, has lost its applicability, yet still persists only to revive and perpetuate penumbral metaphysical associations with the 'nature' of common-sense dualism. We minimize, says Professor Ritter,[2] the grip in which miraculous creation held men's minds. At a time when special or supernatural creation was held as a dogma, 'natural' was the antonym required to make plain the fact that species were not produced by supernatural design. Now, with the latter view long discarded, 'natural' is left to bear the connotation which it had only through reference to a special theological conception.
That natural selection is a term not literally descriptive of fact has been pointed out again and again. Natural selection, we are told, does not really select, but in the next breath it is said that it is a 'principle of extermination.' Although this is more clearly descriptive of the negative influence of the multitude
