The phrase seems to point to a vague notion that there is some such thing as natural good; to a belief that Nature may be said to fix and decide what shall be good, just as she fixes and decides what shall exist. For instance, it may be supposed that ‘health’ is susceptible of a natural definition, that Nature has fixed what health shall be: and health, it may be said, is obviously good; hence in this case Nature has decided the matter; we have only to go to her and ask her what health is, and we shall know what is good: we shall have based an ethics upon science. But what is this natural definition of health? I can only conceive that health should be defined in natural terms as the _normal_ state of an organism for undoubtedly disease is also a natural product. To say that health is what is preserved by evolution, and what itself tends to preserve, in the struggle for existence, the organism which possesses it, comes to the same thing: for the point of evolution is that it pretends to give a causal explanation of why some forms of life are normal and others are abnormal; it explains the origin of species. When therefore we are told that health is natural, we may presume that what is meant is that it is normal; and that when we are told to pursue health as a natural end, what is implied is that the normal must be good. But is it so obvious that the normal must be good? Is it really obvious that health, for instance, is good? Was the excellence of Socrates or of Shakespeare normal? Was it not rather abnormal, extraordinary? It is, I think, obvious in the first place, that not all that is good is normal; that, on the contrary, the abnormal is often better than the normal: peculiar excellence, as well as peculiar viciousness, must obviously be not normal but abnormal. Yet it may be said that nevertheless the normal is good; and I myself am not prepared to dispute that health is good. What I contend is that this must not be taken to be obvious; that it must be regarded as an open question. To declare it to be obvious is to suggest the naturalistic fallacy: just as, in some recent books, a proof that genius is diseased, abnormal, has been used in order to suggest that genius ought not to be encouraged. Such reasoning is fallacious, and dangerously fallacious. The fact is that in the very words ‘health’ and ‘disease’ we do commonly include the notion that the one is good and the other bad. But, when a so-called scientific definition of them is attempted, a definition in natural terms, the only one possible is that by way of ‘normal’ and ‘abnormal.’ Now, it is easy to prove that some things commonly thought excellent are abnormal; and it follows that they are diseased. But it does not follow, except by virtue of the naturalistic fallacy, that those things, commonly thought good, are therefore bad. All that has really been shewn is that in some cases there is a conflict between the common judgment that genius is good,