It will, of course, be noticed that Evolution is thus a _process_, and not a _cause_. It is the method in which certain changes have been brought about, and not the cause which brings them about. Every slight modification must have been caused somehow. When such modifications were caused, then Natural Selection can explain how the useful ones alone were perpetuated, but it cannot explain how the modifications themselves arose. On the contrary, it supposes them as already existing, otherwise there would be nothing to select from. Natural Selection, then, rather weeds than plants, and would be better described as Natural _Rejection_. It merely shows how, as a rule, among the various modifications in an organism, some good and some bad, the useless ones would disappear, and the useful ones would remain; in other words, how the fittest would survive. But this survival of the fittest does not explain in the slightest degree how the fitness arose. If, as an extreme example, out of a hundred animals, fifty had eyes and fifty had not, it is easy to understand how those that had eyes would be more likely to have descendants; but this does not explain how they first got eyes. And the same applies in other cases. How, then, did the variations in each organism first arise? In common language they may be ascribed to chance; but, strictly speaking, such a thing is impossible. The word _chance_ is merely a convenient term for the results of certain forces of nature when we are unable to calculate them. Chance, then, must be excluded; and there seem to be only two alternatives. Either the organisms in nature possessed free will, and acted as they did _voluntarily_; or else they did not possess free will, and acted as they did _necessarily_. The former theory will be examined later on; the latter is the one we are now considering. (2.) _The effect of Evolution._ How then would this theory affect our previous conclusion that the Creator designed all the organs of nature, such as the eye, and hence presumably the whole of the universe? As we shall see, it only confirms it. For to put it plainly, if all free will on the part of the organisms is excluded, so that they were all bound to act exactly as they did, it is clear that the earth and all it contains is like a vast mass of machinery. And however complicated its parts, and however much they may act on one another, and however long they may take in doing so, yet if in the end they produce an organ showing design, this must have been foreseen and intended by the Maker of the machinery. In the same way if a mass of machinery after working for a long time eventually turned out a watch, we should have no hesitation in saying that whoever made the machinery, and set it going, intended it to do so. And is the inference less clear, if it not only turned out a watch, but a watchmaker as well, and everything else that exists on this planet?