Using the name hedonism for that ethical theory which makes happiness the end of action; and distinguishing hedonism into the two kinds, egoistic and universalistic, according as the happiness sought is that of the actor himself or is that of all, Mr. Sidgwick alleges its implied belief to be that pleasures and pains are commensurable. In his criticism on (empirical) egoistic hedonism he says:— (§57 ¶1)

The fundamental assumption of Hedonism, clearly stated, is that all feelings considered merely as feelings can be arranged in a certain scale of desirability, so that the desirability or pleasantness of each bears a definite ratio to that of all the others. (§57 ¶2)

—Methods of Ethics, 2nd ed. p. 115.

And asserting this to be its assumption, he proceeds to point out difficulties in the way of the hedonistic calculation; apparently for the purpose of implying that these difficulties tell against the hedonistic theory. (§56 ¶3)

Now though it may be shown that by naming the intensity, the duration, the certainty, and the proximity, of a pleasure or a pain, as traits entering into the estimation of its relative value, Bentham has committed himself to the specified assumption; and though it is perhaps reasonably taken for granted that hedonism as represented by him, is identical with hedonism at large; yet it seems to me that the hedonist, empirical or other, is not necessarily committed to this assumption. That the greatest surplus of pleasures over pains ought to be the end of action, is a belief which he may still consistently hold after admitting that the valuations of pleasures and pains are commonly vague and often erroneous. He may say that though indefinite things do not admit of definite measurements, yet approximately true estimates of their relative values may be made when they differ considerably; and he may further say that even when their relative values are not determinable, it remains true that the most valuable should be chosen. Let us listen to him. (§56 ¶4)

A debtor who cannot pay me, offers to compound for his debt by making over one of sundry things he possesses—a diamond ornament, a silver vase, a picture, a carriage. Other questions being set aside, I assert it to be my pecuniary interest to choose the most valuable of these; but I cannot say which is the most valuable. Does the proposition that it is my pecuniary interest to choose the most valuable therefore become doubtful? Must I not choose as well as I can; and if I choose wrongly must I give up my ground of choice? Must I infer that in matters of business I may not act on the principle that, other things equal, the more profitable transaction is to be preferred; because in many cases I cannot say which is the more profitable, and have often chosen the less profitable? Because I believe that of many dangerous courses I ought to take the least dangerous, do I make the fundamental assumption that courses can be arranged according to a scale of dangerousness; and must I abandon my belief if I cannot so arrange them? If I am not by consistency bound to do this, then I am no more by consistency bound to give up the principle that the greatest surplus of pleasures over pains should be the end of action, because the commensurability of pleasures and pains cannot be asserted. (§57 ¶5)

At the close of his chapters on empirical hedonism, Mr. Sidgwick himself says he does not think that the common experience of mankind, impartially examined, really sustains the view that Egoistic Hedonism is necessarily suicidal; adding, however, that the uncertainty of hedonistic calculation cannot be denied to have great weight. But here the fundamental assumption of hedonism, that happiness is the end of action, is still supposed to involve the assumption that feelings can be arranged in a certain scale of desirability. This we have seen it does not: its fundamental assumption is in no degree invalidated by proof that such arrangement of them is impracticable. (§57 ¶6)

To Mr. Sidgwick’s argument there is the further objection, no less serious, that to whatever degree it tells against egoistic hedonism, it tells in a greater degree against universalistic hedonism, or utilitarianism. He admits that it tells as much; saying whatever weight is to be attached to the objections brought against this assumption [the commensurability of pleasures and pains] must of course tell against the present method. Not only does it tell, but it tells in a double way. I do not mean merely that, as he points out, the assumption becomes greatly complicated if we take all sentient beings into account, and if we include posterity along with existing individuals. I mean that, taking as the end to be achieved the greatest happiness of the existing individuals forming a single community, the set of difficulties standing in the way of egoistic hedonism, is compounded with another set of difficulties no less great, when we pass from it to universalistic hedonism. For if the dictates of universalistic hedonism are to be fulfilled, it must be under the guidance of individual judgments, or of corporate judgments, or of both. Now any one of such judgments issuing from a single mind, or from any aggregate of minds, necessarily embodies conclusions respecting the happinesses of other persons; few of them known, and the great mass never seen. All these persons have natures differing in countless ways and degrees from the natures of those who form the judgments; and the happinesses of which they are severally capable differ from one another, and differ from the happinesses of those who form the judgments. Consequently, if against the method of egoistic hedonism there is the objection that a man’s own pleasures and pains, unlike in their kinds, intensities, and times of occurrence, are incommensurable; then against the method of universalistic hedonism it may be urged that to the incommensurability of each judge’s own pleasures and pains (which he must use as standards) has now to be added the much more decided incommensurability of the pleasures and pains which he conceives to be experienced by innumerable other persons, all differently constituted from himself and from one another. (§57 ¶7)

Nay more—there is a triple set of difficulties in the way of universalistic hedonism. To the double indeterminateness of the end has to be added the indeterminateness of the means. If hedonism, egoistic or universalistic, is to pass from dead theory into living practice, acts of one or other kind must be decided on to achieve proposed objects; and in estimating the two methods we have to consider how far the fitness of the acts respectively required can be judged. If, in pursuing his own ends, the individual is liable to be led by erroneous opinions to adjust his acts wrongly, much more liable is he to be led by erroneous opinions to adjust wrongly more complex acts to the more complex ends constituted by other men’s welfares. It is so if he operates singly to benefit a few others; and it is still more so if he co-operates with many to benefit all. Making general happiness the immediate object of pursuit, implies numerous and complicated instrumentalities officered by thousands of unseen and unlike persons, and working on millions of other persons unseen and unlike. Even tile few factors in this immense aggregate of appliances and processes which are known, are very imperfectly known; and the great mass of them are unknown. So that even supposing valuation of pleasures and pains for the community at large is more practicable than, or even as practicable as, valuation of his own pleasures and pains by the individual; yet the ruling of conduct with a view to the one end is far more difficult than the ruling of it with a view to the .other. Hence if the method of egoistic hedonism is unsatisfactory, far more unsatisfactory for the same and kindred reasons, is the method of universalistic hedonism, or utilitarianism. (§57 ¶8)

And here we come in sight of the conclusion which it has been the purpose of the foregoing criticism to bring into view. The objection made to the hedonistic method contains a truth, but includes with it an untruth. For while the proposition that happiness, whether individual or general, is the end of action, is not invalidated by proof that it cannot under either form be estimated by measurement of its components; yet it may be admitted that guidance in the pursuit of happiness by a mere balancing of pleasures and pains, is, if partially practicable throughout a certain range of conduct, futile throughout a much wider range. It is quite consistent to assert that happiness is the ultimate aim of action, and at the same time to deny that it can be reached by making it the immediate aim. I go with Mr. Sidgwick as far as the conclusion that we must at least admit the desirability of confirming or correcting the results of such comparisons [of pleasures and pains] by any other method upon which we may find reason to rely; and I then go further, and say that throughout a large part of conduct guidance by such comparisons is to be entirely set aside and replaced by other guidance. (§57 ¶9)