Korschinsky and the Moderns. (3) All fully developed species persist, but through heterogenesis a splitting up into new forms may take place, and this is accompanied by a disturbance of the vital equilibrium. The new state is at first insecure and fluctuating, and only gradually becomes stable. Thus new forms and races arise with gradual consolidation of their constitution.
Darwin. (4) The sharper and more acute the effect of the environment, the keener is the struggle for existence, and the more rapidly and certainly do new forms arise.
Korschinsky and the Moderns. (4) Only in specially favourable conditions, only when the struggle for existence is weak, or when there is none, can new forms arise and become fixed. When the conditions are severe no new forms arise, or if they do they are speedily eliminated.
Darwin. (5) The chief condition of evolution is therefore the struggle for existence and the selection which this involves.
Korschinsky and the Moderns. (5) The struggle for existence simply decimates the overwhelming [pg 184] abundance of possible forms. Where it occurs it prevents the establishment of new variations, and in reality stands in the way of new developments. It is rather an unfavourable than an advantageous factor.
Darwin. (6) If there were no struggle for existence there would be no adaptation, no perfecting.
Korschinsky and the Moderns. (6) Were there no struggle for existence, there would be no destruction of new forms, or of forms in process of arising. The world of organisms would then be a colossal genealogical tree of enormous luxuriance, and with an incalculable wealth of forms.
Darwin. (7) Progress in nature, the “perfecting” of organisms, is only an increasingly complex and ever more perfect adaptation to the external circumstances. It is attained by purely mechanical methods, by an accumulation of the variations most useful at the time.
Korschinsky and the Moderns. (7) The adaptation which the struggle for existence brings about has nothing to do with perfecting, for the organisms which are physiologically and morphologically higher are by no means always better adapted to external circumstances than those lower in the scale. Evolution cannot be explained mechanically. The origin of higher forms from lower is only possible if there is a tendency to progress innate in the organism itself. This tendency is nearly related to or identical with the tendency to variation. It compels the organism to perfect itself as far as external circumstances will permit.
All this implies an admission of evolution and of descent, but a setting aside of Darwinism proper as an unsuccessful hypothesis, and a positive recognition of [pg 185] an endeavour after an aim, internal causes, and teleology in nature, as against fortuitous and superficial factors. This opens up a vista into the background of things, and thereby yields to the religious conception all that a study of nature can yield—namely, an acknowledgment of the possibility and legitimacy of interpreting the world in a religious sense, and assistance in so doing.