By means of natural law we can pass from any event in nature to any other event, just as by the merchant’s books he can pass--say--from a necktie to a delivery truck. But, just as unprecedented kinds of goods may be bought and sold without interrupting the system, so unprecedented natural events may occur, and unprecedented forms of life may appear, without any breach of continuity. Evolution is, indeed, not repetition of the same, but the bringing forth of that which is not the same. Expectancy is the atmosphere appropriate to it. Not that progress is implicit in evolution as such, but rather plasticity, roominess, and versatility. The fact that usually the development of new organs and new species takes place through the gradual accumulation of slight changes does not alter the logic of the situation; gradualness of change does not mean sameness. Even if it did, the fact of mutations would still confront us. As we have bodily organs that once were non-existent anywhere in our world-system, so we perform functions that are special to us. Instances will be given in a moment; but before going on to them, it is worth remarking that the argument from kinship to sameness works just as well backward as forward. If it be maintained that the blood relationship between an Abraham Lincoln and a coyote implies that the impulsions of the two are the same, it then becomes just as legitimate--and illegitimate--to interpret the coyote by Lincoln as the reverse. Let us now examine a case or two of our immersion within the totality of animate nature. The statement has been made that the whole of human conduct turns upon two fundamental drives, the appetite for food and the appetite for sex. The reasoning by which this broad generalization is supported starts with the assumption that survival is the all-inclusive objective of organic impulses. Survival means, however, according to circumstances, either continuance of an individual life, or maintenance of a species. Nutrition, it is said, is the basic condition of individual survival; reproduction, that of species survival. Hence the conclusion is drawn that human life is ruled by just two drives, each proliferating into many details, the drive for food and the drive for sex-intercourse. The theory has the attractiveness of simplicity, at least apparent simplicity; but it is the simplicity of abstractions substituted for the complexity of concrete facts. First of all, “survival,” “individual,” and “species” are our after-thoughts, products of our reflection and systematization. They are not a description of the facts of animal conduct or of human conduct. We can perceive that a given act is related to survival, but this by no means proves that survival was in any sense an objective of the act.