The fact that some philosophers deny the importance of the evolutionary method for ethics, holding that morality is purely a matter of value, and that the evolutionary method tends only to obscure differences of value, makes it necessary to inquire into the import and nature of this method. "Anyway," Dewey says, "before we either abuse or recommend genetic method we ought to have some answers to these questions: Just what is it? Just what is to come of it and how?"[148] The experimental method in science has at least some of the traits of a genetic method. The nature of water, for instance, cannot be determined by simply observing it. But experiment brings to light the exact conditions under which it came into being and therefore explains it. "Through generating water we single out the precise and sole conditions which have to be fulfilled that water may present itself as an experienced fact. If this case be typical, then the experimental method is entitled to rank as genetic method; it is concerned with the manner or process by which anything comes into experienced existence."[149] Some would deny this, on the ground that a genuinely historical event occupies a particular place in a historical series, from which it is inseparable, while in experimental science the sets or pairs of terms are not limited to any particular place in a historical series, but occur and recur. "Water is made over and over again, and, so to speak, at any date in the cosmic series. This deprives any account of it of genuinely historic quality."[150] Again, it might be said in opposition to treating the experimental method as a genetic method, that it is interested in individual cases not as such, but as samples or instances. The particular case is only an illustration of the general relation which is being sought. It will turn out in the course of the discussion, Dewey says, that, although science deals with origins, it is not, in strictness, a historical discipline. The distinction between the historical and other sciences is based on an abstraction, which has been introduced for the sake of more adequate control. It is only by abstraction that we get the pairs of facts that may show up at any time, and by abstraction we attribute to them a generalized character. The facts, in themselves, are historic.