life has been on the whole progressive; but progress and retrogression have both been effected under the same law of Natural Selection. How, then, can the credit of that result be ascribed to Natural Selection? Natural Selection is equally ready to bring about degeneration or to leave things unchanged. How, then, can it be that which determines which of the three possible (and actual) cases shall be realized?... It cannot be Natural Selection that causes one species to remain stationary, another to degenerate, a third to develop into a higher form.... Some variable factor must be added to Natural Selection. But why? Evolution, as we have pointed out in a previous chapter, makes for adaptation in terms of animal preservation. If the adaptation of an animal to its environment is secured by "degenerating" or "developing" or by remaining stationary, it will do one of the three. That is the normal consequence of Natural Selection, and it is surprising that Mr. Schiller does not see this. He is actually accusing Natural Selection of not being able to do what it does on his own showing. The proof he himself gives of this operation of Natural Selection in the examples he cites of its ineffectiveness. If Natural Selection could not make for degeneration or development, in what way would it be able to establish an equilibrium between an animal and its surroundings? Really, there is nothing that so strengthens one's conviction of the truth of the Freethought position so much as a study of the arguments that are brought against it. Mr. Schiller is really misled, and so misleads his readers by an unjustifiable use of the word "progress." He says that evolution has been, on the whole, progressive, and appeals to "progress" as though it were some objective fact. But that is not the case. There is no "progress" in the animal world, there is only change. We have dealt with this in a previous chapter, and there is no need to again labour the point. "Progress" is a conception which we ourselves frame, and we measure a movement towards or away from this arbitrary standard of ours in terms of better or worse, higher or lower. But nature knows nothing of a higher or a lower, it knows only of changing forms more or less fitted to live in the existing environment. Scientifically, life has not progressed, it has persisted, and a _sine qua non_ of its persistence has been adaptation to environment.