In what way can the nature of supersensible reality possibly have a bearing upon Ethics? (§ 68 ¶ 1)

I have distinguished two kinds of ethical questions, which are far too commonly confused with one another. Ethics, as commonly understood, has to answer both the question What ought to be? and the question What ought we to do? The second of these questions can only be answered by considering what effects our actions will have. A complete answer to it would give us that department of Ethics which may be called the doctrine of means or practical Ethics. And upon this department of ethical enquiry it is plain that the nature of a supersensible reality may have a bearing. If, for instance, Metaphysics could tell us not only that we are immortal, but also, in any degree, what effects our actions in this life will have upon our condition in a future one, such information would have an undoubted bearing upon the question what we ought to do. The Christian doctrine of heaven and hell are in this way highly relevant to practical Ethics. But it is worthy of notice that the most characteristic doctrines of Metaphysics are such as either have no such bearing upon practical Ethics or have a purely negative bearing—involving the conclusion that there is nothing which we ought to do at all. They profess to tell us the nature not of a future reality, but of one that is eternal and which therefore no actions of ours can have power to alter. Such information may indeed have relevance to practical Ethics, but it must be of a purely negative kind. For, if it holds, not only that such an eternal reality exists, but also, as is commonly the case, that nothing else is real—that nothing either has been, is now, or will be real in time—then truly it will follow that nothing we can do will ever bring any good to pass. For it is certain that our actions can only affect the future; and if nothing can be real in the future, we can certainly not hope ever to make any good thing real. It would follow, then, that there can be nothing which we ought to do. We cannot possibly do any good; for neither our efforts, nor any result which they may seem to effect, have any real existence. But this consequence, though it follows strictly from many metaphysical doctrines, is rarely drawn. Although a metaphysician may say that nothing is real but that which is eternal, he will generally allow that there is some reality also in the temporal: and his doctrine of an eternal reality need not interfere with practical Ethics, if he allows that, however good the eternal reality may be, yet some things will also exist in time, and that the existence of some will be better than that of others. It is, however, worth while to insist upon this point, because it is rarely fully realised. (§ 68 ¶ 2)

If it is maintained that there is any validity at all in practical Ethics—that any proposition which asserts We ought to do so and so can have any truth—this contention can only be consistent with the Metaphysics of an eternal reality, under two conditions. One of these is, (1) that the true eternal reality, which is to be our guide, cannot, as is implied by calling it true, be the only true reality. For a moral rule, bidding us realise a certain end, can only be justified, if it is possible that that end should, at least partially, be realised. Unless our efforts can effect the real existence of some good, however little, we certainly have no reason for making them. And if the eternal reality is the sole reality, then nothing good can possibly exist in time: we can only be told to try to bring into existence something which we know beforehand cannot possibly exist. If it is said that what exists in time can only be a manifestation of the true reality, it must at least be allowed that that manifestation is another true reality—a good which we really can cause to exist; for the production of something quite unreal, even if it were possible, cannot be a reasonable end of action. But if the manifestation of that which eternally exists is real, then that which eternally exists is not the sole reality. (§ 68 ¶ 3)

And the second condition which follows from such a metaphysical principle of Ethics, is (2) that the eternal reality cannot be perfect—cannot be the sole good. For just as a reasonable rule of conduct requires that what we are told to realise should be capable of being truly real, so it requires that the realisation of this ideal shall be truly good. It is just that which can be realised by our efforts—the appearance of the eternal in time, or whatsoever else is allowed to be attainable—which must be truly good, if it is to be worth our efforts. That the eternal reality is good, will by no means justify us in aiming at its manifestation, unless that manifestation itself be also good. For the manifestation is different from the reality: its difference is allowed, when we are told that it can be made to exist, whereas the reality itself exists unalterably. And the existence of this manifestation is the only thing which we can hope to effect: that also is admitted. If, therefore, the moral maxim is to be justified, it is the existence of this manifestation, as distinguished from the existence of its corresponding reality, which must be truly good. The reality may be good too: but to justify the statement that we ought to produce anything, it must be maintained, that just that thing itself, and not something else which may be like it, is truly good. If it is not true that the existence of the manifestation will add something to the sum of good in the Universe, then we have no reason to aim at making it exist; and if it is true that it will add something to the sum of good, then the existence of that which is eternal cannot be perfect by itself—it cannot include the whole of possible goods. (§ 68 ¶ 4)

Metaphysics, then, will have a bearing upon practical Ethics—upon the question what we ought to do—if it can tell us anything about the future consequences of our actions beyond what can be established by ordinary inductive reasoning. But the most characteristic metaphysical doctrines, those which profess to tell us not about the future but about the nature of an eternal reality, can either have no bearing upon this practical question or else must have a purely destructive bearing. For it is plain that what exists eternally cannot be affected by our actions; and only what is affected by our actions can have a bearing on their value as means. But the nature of an eternal reality either admits no inference as to the results of our actions, except in so far as it can also give us information about the future (and how it can do this is not plain), or else, if, as is usual, it is maintained to be the sole reality and the sole good, it shews that no results of our actions can have any value whatever. (§ 68 ¶ 5)