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? (§ 73 ¶ 1)

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 of propositions 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 object 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 this that the naturalistic philosophers proper—those who are empiricists—and those whom I have called metaphysical part company. These two classes of philosophers do, indeed, differ with regard to the nature of scientific laws. The former class tend to suppose that they mean only This has accompanied, does now, and will accompany that in these particular instances: they reduce the scientific law quite simply and directly to the familiar type of proposition which I have pointed out. But this does not satisfy the metaphysicians. They see that when you say This would accompany that, if that existed, you don't mean only that this and that have existed and will exist together so many times. But it is beyond even their powers to believe that what you do mean is merely what you say. They still think you must mean, somehow or other, that something does exist, since that is what you generally mean when you say anything. They are as unable as the empiricists to imagine that you can ever mean that 2+2=4. The empiricists say this means that so many couples of couples of things have in each case been four things; and hence that 2 and 2 would not make 4, unless precisely those things had existed. The metaphysicians feel that this is wrong; but they themselves have no better account of its meaning to give than either, with Leibniz, that God's mind is in a certain state, or, with Kant, that your mind is in a certain state, or finally, with Mr Bradley, that something is in a certain state. Here, then, we have the root of the naturalistic fallacy. The metaphysicians have the merit of seeing that when you say This would be good, if it existed, you can't mean merely This has existed and was desired, however many times that may have been the case. They will admit that some good things have not existed in this world, and even that some may not have been desired. But what you can mean, except that something exists, they really cannot see. Precisely the same error which leads them to suppose that there must exist a supersensible Reality, leads them to commit the naturalistic fallacy with regard to the meaning of good. Every truth, they think, must mean somehow that something exists; and since, unlike the empiricists, they recognise some truths which do not mean which do not mean that anything exists here and now, these they think must mean that something exists not here and now. On the same principle, since good is a predicate which neither does nor can exist, they are bound to suppose either that to be good means to be related to some other particular thing which can exist and does exist in reality; or else that it means merely to belong to the real world—that goodness is transcended or absorbed in reality. (§ 73 ¶ 2)