has some claim to be called metaphysical, I shall not attempt to deal with it here. But the same phrase reappears in Rousseau; and it is not unfrequently maintained even now that what we ought to do is live naturally. Now let us examine this contention in its general form. It is obvious, in the first place, that we cannot say that everything natural is good, except perhaps in virtue of some metaphysical theory, such as I shall deal with later. If everything natural is equally good, then certainly Ethics, as it is ordinarily understood, disappears; for nothing is more certain, from an ethical point of view, than that some things are bad and others good; the object of Ethics is, indeed, in chief part, to give you general rules whereby you may avoid the one and secure the other. What, then, does ‘natural’ mean, in this advice to live naturally, since it obviously cannot apply to everything that is natural?
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
