Principia Ethica

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 when they say “This always accompanies 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 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.

74. That such a reduction of all propositions to the type of those which assert either that something exists or that something which exists has a certain attribute (which means, that both exist in a certain relation to one another), is erroneous, may easily be seen by reference to the particular class of ethical propositions. For whatever we may have proved to exist, and whatever two existents we may have proved to be necessarily connected with one another, it still remains a distinct and different question whether what thus exists is good; whether either or both of the two existents is so; and whether it is good that they should exist together. To assert the one is plainly and obviously not the same thing as to assert the other. We understand what we mean by asking: Is this, which exists, or necessarily exists, after all, good? and we perceive that we are asking a question which has not been answered. In face of this direct perception that the two questions are distinct, no proof that they must be identical can have the slightest value. That the proposition “This is good” is thus distinct from every other proposition was proved in Chapter I; and I may now illustrate this fact by pointing out how it is distinguished from two particular propositions with which it has commonly been identified. That so-and-so ought to be done is commonly called a moral law, and this phrase naturally suggests that this proposition is in some way analogous either to a natural law, or to a law in the legal sense, or to both. All three are, in fact, really analogous in one respect, and in one respect only: that they include a proposition which is universal. A moral law asserts “This is good in all cases”; a natural law asserts “This happens in all cases”; and a law, in the legal sense, “It is commanded that this be done, or be left undone, in all cases.” But since it is very natural to suppose that the analogy extends further, and that the assertion “This is good in all cases” is equivalent to the assertion “This happens in all cases” or to the assertion “It is commanded that this be done in all cases,” it may be useful briefly to point out that they are not equivalent.

75. The fallacy of supposing moral law to be analogous to natural law in respect of asserting that some action is one which is always necessarily done is contained in one of the most famous doctrines of Kant. Kant identifies what ought to be with the law according to which a Free or Pure Will must act⁠—with the only kind of action which is possible for it. And by this identification he does not mean merely to assert that the Free Will is also under the necessity of doing what it ought; he means that what it ought to do means nothing but its own law⁠—the law according to which it must act. It differs from the human will