72. We may, then, attribute the obstinate prejudice that a knowledge of supersensible reality is a necessary step to a knowledge of what is good in itself, partly to a failure to perceive that the subject of the latter judgment is not anything real as such, and partly to a failure to distinguish the cause of our perception of a truth from the reason why it is true. But these two causes will carry us only a very little way in our explanation of why Metaphysics should have been supposed to have a bearing upon Ethics. The first explanation which I have given would only account for the supposition that a thing’s reality is a necessary condition for its goodness. This supposition is, indeed, commonly made; we find it commonly presupposed that unless a thing can be shown to be involved in the constitution of reality, it cannot be good. And it is, therefore, worth while to insist that this is not the case; that Metaphysics is not even necessary to furnish part of the basis of Ethics. But when metaphysicians talk of basing Ethics on Metaphysics they commonly mean much more than this. They commonly mean that Metaphysics is the sole basis of Ethics—that it furnishes not only one necessary condition but all the conditions necessary to prove that certain things are good. And this view may, at first sight, appear to be held in two different forms. It may be asserted that merely to prove a thing supersensibly real is sufficient to prove it good: that the truly real must, for that reason alone, be truly good. But more commonly it appears to be held that the real must be good because it possesses certain characters. And we may, I think, reduce the first kind of assertion to no more than this. When it is asserted that the real must be good, because it is real, it is commonly also held that this is only because, in order to be real, it must be of a certain kind. The reasoning by which it is thought that a metaphysical enquiry can give an ethical conclusion is of the following form. From a consideration of what it is to be real, we can infer that what is real must have certain supersensible properties: but to have these properties is identical with being good—it is the very meaning of the word: it follows therefore that what has these properties is good: and from a consideration of what it is to be real, we can again infer what it is that has these properties. It is plain that, if such reasoning were correct, any answer which could be given to the question “What is good in itself?” could be arrived at by a purely metaphysical discussion and by that alone. Just as, when Mill supposed that “to be good” meant “to be desired,” the question “What is good?” could be and must be answered solely by an empirical investigation of the question what was desired; so here, if to be good means to have some supersensible property, the ethical question can and must be answered by a metaphysical enquiry into the question, What has this property? What, then, remains to be done in order to destroy the plausibility of Metaphysical Ethics, is to expose the chief errors which seem to have led metaphysicians to suppose that to be good means to possess some supersensible property.
73. What, then, are the chief reasons which have made it seem plausible to maintain that to be good must mean to possess some supersensible property or to be related to some supersensible reality?
We may, first of all, notice one, which seems to have had some influence in causing the view that good must be defined by some such property, although it does not suggest any particular property as the one required. This reason lies in the supposition that the proposition “This is good” or “This would be good, if it existed” must, in a certain respect, be of the same type as other propositions. The fact is that there is one type of proposition so familiar to everyone, and therefore having such a strong hold upon the imagination, that philosophers have always supposed that all other types must be reducible to it. This type is that of the objects of experience—of all those truths which occupy our minds for the immensely greater part of our waking lives: truths such as that somebody is in the room, that I am writing or eating or talking. All these truths, however much they may differ, have this in common that in them both the grammatical subject and the grammatical predicate stand for something which exists. Immensely the commonest type of truth, then, is one which asserts a relation between two existing things. Ethical truths are immediately felt not to conform to this type, and the naturalistic fallacy arises from the attempt to make out that, in some roundabout way, they do conform to it. It is immediately obvious that when we see a thing to be good, its goodness is not a property which we can take up in our hands, or separate from it even by the most delicate scientific instruments, and transfer to something else. It is not, in fact, like most of the predicates which we ascribe to things, a part of the thing to which we ascribe it. But philosophers suppose that the reason why we cannot take goodness up and move it about, is not that it is a different kind of object from any which can be moved about, but only that it necessarily exists together with anything with which it does exist. They explain the type of ethical truths by supposing it identical with the type of scientific laws. And it is only when they have done
