(b) We must assume, then, that if the effects of one action are generally better than those of another, so far forward in the future as we are able to forsee any probable difference in their effects at all, then the total effect upon the Universe of the former action is also generally better. We certainly cannot hope directly to compare their effects except within a limited future; and all the arguments, which have ever been used in Ethics, and upon which we commonly act in common life, directed to shewing that one course is superior to another, are (apart from theological dogmas) confined to pointing out such probable immediate advantages. The question remains then; Can we lay down any general rules to the effect that one among a few alternative actions will generally produce a greater total of good in the immediate future? (§ 94 ¶ 1)

It is important to insist that this question, limited as it is, is the utmost, to which, with any knowledge we have at present or are likely to have for a long time to come, Practical Ethics can hope to give an answer. I have already pointed out that we cannot hope to discover which is the best possible alternative in any given circumstances, but only which, among a few, is better than the others. And I have also pointed out that there is certainly no more than a probability, even if we are entitled to assert so much, that what is better in regard to its immediate effects will also be better on the whole. It now remains to insist that, even with regard to these immediate effects, we can only hope to discover which, among a few alternatives, will generally produce the greatest balance of good in the immediate future. We can secure no title to assert that obedience to such commands as Thou shalt not lie, or even Thou shalt do no murder, is universally better than the alternatives of lying and murder. Reasons why no more than a general knowledge is possible have already been given in Chap. I. (§ 16); but they may be recapitulated here. In the first place, of the effects, which principally concern us in ethical discussions, as having intrinsic value, we know the causes so little, that we can scarcely claim, with regard to any single one, to have obtained even a hypothetical universal law, such as has been obtained in the exact sciences. We cannot even say: If this action is performed, under exactly these circumstances, and if no others interfere, this important effect, at least, will always be produced. But, in the second place, an ethical law is not merely hypothetical. If we are to know that it will always be better to act in a certain way, under certain circumstances, we must know not merely wha effects such actions will produce, provided no other circumstances interfere, but also that no other circumstances will interfere. And this it is obviouisly impossible to know with more than probability. An ethical law has the nature not of a scientific law but of a scientific prediction: and the latter is always merely probable, although the probability may be very great. An engineer is entitled to assert that, if a bridge be built in a certain way, it will probably bear certain loads for a certain time; but he can never be absolutely certain that it has been built in the way required, nor that, even if it has, some accident will not intervene to falsify his prediction. With any ethical law, the same must be the case; it can be no more than a generalisation: and here, owing to the comparative absence of accurate hypothetical knowledge, on which the prediction should be based, the probability is comparatively small. But finally, for an ethical generalisation, we require to know not only what effects will be produced, but also what are the comparative values of those effects; and on this question too, it must be admitted, considering what a prevalent opinion Hedonism has been, that we are very likely to be mistaken. It is plain, then, that we are not soon likely to know more than that one kind of action will generally produce better effects than another; and that more than this has certainly never been proved. In no two cases will all the effects of any kind of action be precisely the same, because in each case some of the circumstances will differ; and although the effects, that are important for good or evil, may be generally the same, it is extremely unlikely that they will always be so. (§ 94 ¶ 2)