In preparing this work for the second edition, I have found it desirable to make numerous alterations and additions. Indeed the extent which these have reached is so considerable, that I have thought it well to publish them in a separate form, for the use of purchasers of my first edition. On one or two points I have to acknowledge a certain change of view; which is partly at least due to criticism. For instance, in chap. iv. of Book i. (on ``Pleasure and Desire''), which has been a good deal criticised by Prof. Bain and others, although I still retain my former opinion on the psychological question at issue, I have been led to take a different view of the relation of this question to Ethics; and in fact §1 of this chapter as it at present stands directly contradicts the corresponding passage in the former edition. So again, as regards the following chapter, on `Free-Will', though I have not exactly found that the comments which it has called forth have removed my difficulties in dealing with this time-honoured problem, I have become convinced that I ought not to have crudely obtruded these difficulties on the reader, while professedly excluding the consideration of them from my subject. In the present edition therefore I have carefully limited myself to explaining and justifying the view that I take of the practical aspect of the question. I have further been led, through study of the Theory of Evolution in its application to practice, to attach somewhat more importance to this theory than I had previously done; and also in several passages of Books iii. and iv. to substitute `well-being' for `happiness', in my exposition of that implicit reference to some further end and standard which reflection on the Morality of Common Sense continually brings into view. This latter change however (as I explain in the concluding chapter of Book iii.) is not ultimately found to have any practical effect. I have also modified my view of `objective rightness', as the reader will see by comparing Book i. chap. i. §3 with the corresponding passage in the former edition but here again the alteration has no material importance. In my exposition of the Utilitarian principle (Book iv. chap. i.) I have shortened the cumbrous phrase 'greatest happiness of the greatest number' by omitting---as its author ultimately advised---the last four words. And finally, I have yielded as far as I could to the objections that have been strongly urged against the concluding chapter of the treatise. The main discussion therein contained still seems to me indispensable to the completeness of the work; but I have endeavoured to give the chapter a new aspect by altering its commencement, and omitting most of the concluding paragraph.
The greater part, however, of the new matter in this edition is merely explanatory and supplementary. I have endeavoured to give a fuller and clearer account of my views on any points on which I either have myself seen them to be ambiguously or inadequately expressed, or have found by experience that they were liable to be misunderstood. Thus in Book i. chap. ii. I have tried to furnish a rather more instructive account than my first edition contained of the mutual relations of Ethics and Politics. Again, even before the appearance of Mr. Leslie Stephen's interesting review in Fraser (March 1875), I had seen the desirability of explaining further my general view of the `Practical Reason', and of the fundamental notion signified by the terms `right', `ought', etc. With this object I have entirely rewritten chap. iii. of Book i., and made considerable changes in chap. i. Elsewhere, as in chaps. vi. and ix. of Book i., and chap. vi of Book ii, I have altered chiefly in order to make my expositions more clear and symmetrical. This is partly the case with the considerable changes that I have made in the first three chapters of Book iii.; but I have also tried to obviate the objections brought by Professor Calderwood against the first of these chapters. The main part of this Book (chaps. iv.--xii.) has been but slightly altered; but in chap. xiii. (on `Philosophical Intuitionism'), which has been suggestively criticised by more that one writer, I have thought it expedient to give a more direct statement of my own opinions; instead of confining myself (as I did in the first edition) to comments on those of other moralists. Chap. xiv. again has been considerably modified; chiefly in order to introduce into it the substance of certain portions of an article on `Hedonism and Ultimate Good', which I published in Mind (No. 5). In Book iv. the changes (besides those above mentioned) have been inconsiderable; and have been chiefly made in order to remove a misconception which I shall presently notice, as to my general attitude towards the three Methods which I am principally occupied in examining.
In revising my work, I have endeavoured to profit as much as possible by all the criticisms on it that have been brought to my notice, whether public or private. I have frequently deferred to objections, even when they appeared to me unsound, if I thought I could avoid controversy by alterations to which I was myself indifferent. Where I have been unable to make the changes required, I have usually replied, in the text or the notes, to such criticisms as have appeared to me plausible, or in any way instructive. In so doing, I have sometimes referred by name to opponents, where I thought that, from their recognised position as teachers of the subject, this would give a distinct addition of interest to the discussion; but I have been careful to omit such reference where experience has shown that it would be likely to cause offence. The book is already more controversial than I could wish; and I have therefore avoided encumbering it with any polemics of purely personal interest. For this reason I have generally left unnoticed such criticisms as have been due to mere misapprehensions, against which I thought I could effectually guard in the present edition. There is, however, one fundamental misunderstanding, on which it seems desirable to say a few words. I find that more than one critic has overlooked or disregarded the account of the plan of my treatise, given in the original preface and in §5 of the introductory chapter: and has consequently supposed me to be writing as an assailant of two of the methods which I chiefly examine, and a defender of the third. Thus one of my reviewers seems to regard Book iii. (on Intuitionism) as containing mere hostile criticism from the outside: another has constructed an article on the supposition that my principal object is the `suppression of Egoism': a third has gone to the length of a pamphlet under the impression (apparently) that the `main argument' of my treatise is a demonstration of Universalistic Hedonism. I am concerned to have caused so much misdirection of criticism: and I have carefully altered in this edition the passages which I perceive to have contributed to it. The morality that I examine in Book iii. is my own morality as much as it is any man's: it is, as I say, the `Morality of Common Sense', which I only attempt to represent in so far as I share it; I only place myself outside it either (1) temporarily, for the purpose of impartial criticism, or (2) in so far as I am forced beyond it by a practical consciousness of its incompleteness. I have certainly criticised this morality unsparingly: but I conceive myself to have exposed with equal unreserve the defects and difficulties of the hedonistic method (cf. especially chaps. iii., iv. of Book ii., and chap. v. of Book iv.). And as regards the two hedonistic principles, I do not hold the reasonableness of aiming at happiness generally with any stronger conviction than I do that of aiming at one's own. It was no part of my plan to call special attention to this ``Dualism of the Practical Reason'' as I have elsewhere called it: but I am surprised at the extent to which my view has perplexed even those of my critics who have understood it. I had imagined that they would readily trace it to the source from which I learnt it, Butler's well-known Sermons. I hold with Butler that ``Reasonable Self-love and Conscience are the two chief or superior principles in the nature of man'', each of which we are under a ``manifest obligation'' to obey: and I do, not (I believe) differ materially from Butler in my view either of reasonable self-love, or---theology apart---of its relation to conscience. Nor, again, do I differ from him in regarding conscience as essentially a function of the practical Reason: ``moral precepts'', he says in the Analogy (Part II. chap. viii.), ``are precepts the reason of which we see''. My difference only begins when I ask myself, `What among the precepts of our common conscience do we really see to be ultimately reasonable' a question which Butler does not seem to have seriously put, and to which, at any rate, he has given no satisfactory answer. The answer that I found to it supplied the rational basis that I had long perceived to be wanting to the Utilitarianism of Bentham, regarded as an ethical doctrine: and thus enabled me to transcend the commonly received antithesis between Intuitionists and Utilitarians.