The revision of The Methods of Ethics for this edition was begun by Professor Sidgwick and carried through by him up to p. 276, on which the last of his corrections on the copy were made. The latter portion of his revision was done under the pressure of severe illness, the increase of which prevented him from continuing it beyond the point mentioned; and by the calamity of his death the rest of the book remains without the final touches which it might have received from his hand. In accordance with his wish, I have seen pp. 277 to 509 through the press unchanged---except for a few small alterations which he had indicated, and the insertion on pp. 457--459 of the concluding passage of Book iv. chapter iii.  Such alterations as were made by Professor Sidgwick in this edition prior to p. 276 will be found chiefly in chapters i.--v. and ix. of Book i, and chapters iii. and vi. of Book ii.
The Appendix on ``The Kantian Conception of Free Will'', promised in note 1 on p. 58 of this edition, is substantially a reprint of a paper by Professor Sidgwick under that heading which appeared in Mind, vol. xiii. No. 51, and accurately covers the ground indicated in the note.
There is one further matter of importance. Among the MS. material which Professor Sidgwick intended to be referred to, in preparing this edition for the press, there occurs, as part of the MS. notes for a lecture, a brief history of the development in his thought of the ethical view which he has set forth in the Methods of Ethics. This, though not in a finished condition, is in essentials complete and coherent, and since it cannot fail to have peculiar value and interest for students of the book, it has been decided to insert it here. Such an arrangement seems to a certain extent in harmony with the author's own procedure in the Preface to the Second Edition; and in this way while future students of the Methods will have access to an introductory account which both ethically and historically is of very exceptional interest, no dislocation of the text will be involved.
In the account referred to Professor Sidgwick says:---
``My first adhesion to a definite Ethical system was to the Utilitarianism of Mill: I found in this relief from the apparently external and arbitrary pressure of moral rules which I had been educated to obey, and which presented themselves to me as to some extent doubtful and confused; and sometimes, even when clear, as merely dogmatic, unreasoned, incoherent. My antagonism to this was intensified by the study of Whewell's Elements of Morality which was prescribed for the study of undergraduates in Trinity. It was from that book that I derived the impression which long remained uneffaced---that Intuitional moralists were hopelessly loose (as compared to mathematicians) in their definitions and axioms.
The two elements of Mill's view which I am accustomed to distinguish as Psychological Hedonism [that each man does seek his own Happiness] and Ethical Hedonism [that each man ought to seek the general Happiness] both attracted me, and I did not at first perceive their incoherence.
Psychological Hedonism---the law of universal pleasure-seeking---attracted me by its frank naturalness. Ethical Hedonism, as expounded by Mill, was morally inspiring by its dictate of readiness for absolute self-sacrifice. They appealed to different elements of my nature, but they brought these into apparent harmony: they both used the same words ``pleasure'', ``happiness'', and the persuasiveness of Mill's exposition veiled for a time the profound discrepancy between the natural end of action---private happiness, and the end of duty---general happiness. Or if a doubt assailed me as to the coincidence of private and general happiness, I was inclined to hold that it ought to be cast to the winds by a generous resolution.
But a sense grew upon me that this method of dealing with the conflict between Interest and Duty, though perhaps proper for practice could not be final for philosophy. For practical men who do not philosophise, the maxim of subordinating self-interest, as commonly conceived, to ``altruistic'' impulses and sentiments which they feel to be higher and nobler is, I doubt not, a commendable maxim; but it is surely the business of Ethical Philosophy to find and make explicit the rational ground of such action.
I therefore set myself to examine methodically the relation of Interest and Duty.
This involved a careful study of Egoistic Method, to get the relation of Interest and Duty clear. Let us suppose that my own Interest is paramount. What really is my Interest, how far can acts conducive to it be known, how far does the result correspond with Duty (or Wellbeing of Mankind)? This investigation led me to feel very strongly this opposition, rather than that which Mill and the earlier Utilitarians felt between so-called Intuitions or Moral Sense Perceptions, and Hedonism, whether Epicurean or Utilitarian. Hence the arrangement of my book-ii., iii., iv. [Book ii. Egoism, Book iii. Intuitionism, Book iv. Utilitarianism].
The result was that I concluded that no complete solution of the conflict between my happiness and the general happiness was possible on the basis of mundane experience. This [conclusion I] slowly and reluctantly accepted---cf. Book ii. chap. v., and last chapter of treatise [Book ii. chap. v. is on ``Happiness and Duty'', and the concluding chapter is on ``The Mutual Relations of the Three Methods'']. This [was] most important to me.
In consequence of this perception, moral choice of the general happiness or acquiescence in self-interest as ultimate, became practically necessary. But on what ground?
I put aside Mill's phrases that such sacrifice was ``heroic'': that it was not ``well'' with me unless I was in a disposition to make it. I put to him in my mind the dilemma:---Either it is for my own happiness or it is not. If not, why [should I do it]? It was no use to say that if I was a moral hero I should have formed a habit of willing actions beneficial to others which would remain in force, even with my own pleasure in the other scale. I knew that at any rate I was not the kind of moral hero who does this without reason; from blind habit. Nor did I even wish to be that kind of hero: for it seemed to me that that kind of hero, however admirable, was certainly not a philosopher. I must somehow see that it was right for me to sacrifice my happiness for the good of the whole of which I am a part.
Thus, in spite of my early aversion to Intuitional Ethics, derived from the study of Whewell, and in spite of my attitude of discipleship to Mill, I was forced to recognise the need of a fundamental ethical intuition.
The utilitarian method---which I had learnt from Mill---could not, it seemed to me, be made coherent and harmonious without this fundamental intuition.
In this state of mind I read Kant's Ethics again: I had before read it somewhat unintelligently, under the influence of Mill's view as to its ``grotesque failure''.  I now read it more receptively and was impressed with the truth and importance of its fundamental principle:---Act from a principle or maxim that you can will to be a universal law---cf. Book iii. chap. i. §3 [of The Methods of Ethics]. It threw the ``golden rule'' of the gospel (``Do unto others as ye would that others should do unto you'') into a form that commended itself to my reason.
Kant's resting of morality on Freedom did not indeed commend itself to me, though I did not at first see, what I now seem to see clearly, that it involves the fundamental confusion of using ``freedom'' in two distinct senses---``freedom'' that is realised only when we do right, when reason triumphs over inclination, and ``freedom'' that is realised equally when we choose to do wrong, and which is apparently implied in the notion of ill-desert. What commended itself to me, in short, was Kant's ethical principle rather than its metaphysical basis. This I briefly explain in Book iii. chap. i. §3 [of The Methods of Ethics]. I shall go into it at more length when we come to Kant.
That whatever is right for me must be right for all persons in similar circumstances---which was the form in which I accepted the Kantian maxim---seemed to me certainly fundamental, certainly true, and not without practical importance.
But the fundamental principle seemed to me inadequate for the construction of a system of duties; and the more I reflected on it the more inadequate it appeared.
On reflection it did not seem to me really to meet the difficulty which had led me from Mill to Kant: it did not settle finally the subordination of Self-Interest to Duty.
For the Rational Egoist---a man who had learnt from Hobbes that Self-preservation is the first law of Nature and Self-interest the only rational basis of social morality---and in fact, its actual basis, so far as it is effective---such a thinker might accept the Kantian principle and remain an Egoist.
He might say, ``I quite admit that when the painful necessity comes for another man to choose between his own happiness and the general happiness, he must as a reasonable being prefer his own, i.e. it is right for him to do this on my principle. No doubt, as I probably do not sympathise with him in particular any more than with other persons, I as a disengaged spectator should like him to sacrifice himself to the general good: but I do not expect him to do it, any more than I should do it myself in his place.''
It did not seem to me that this reasoning could be effectively confuted. No doubt it was, from the point of view of the universe, reasonable to prefer the greater good to the lesser, even though the lesser good was the private happiness of the agent. Still, it seemed to me also undeniably reasonable for the individual to prefer his own. The rationality of self-regard seemed to me as undeniable as the rationality of self-sacrifice. I could not give up this conviction, though neither of my masters, neither Kant nor Mill, seemed willing to admit it: in different ways, each in his own way, they refused to admit it.
I was, therefore, [if] I may so say, a disciple on the loose, in search of a master---or, if the term `master' be too strong, at any rate I sought for sympathy and support, in the conviction which I had attained in spite of the opposite opinions of the thinkers from whom I had learnt most.
It was at this point then that the influence of Butler came in. For the stage at which I had thus arrived in search of an ethical creed, at once led me to understand Butler, and to find the support and intellectual sympathy that I required in his view.
I say to understand him, for hitherto I had misunderstood him, as I believe most people then misunderstood, and perhaps still misunderstand, him. He had been presented to me as an advocate of the authority of Conscience; and his argument, put summarily, seemed to be that because reflection on our impulses showed us Conscience claiming authority therefore we ought to obey it. Well, I had no doubt that my conscience claimed authority, though it was a more utilitarian conscience than Butler's: for, through all this search for principles I still adhered for practical purposes to the doctrine I had learnt from Mill, i.e. I still held to the maxim of aiming at the general happiness as the supreme directive rule of conduct, and I thought I could answer the objections that Butler brought against this view (in the ``Dissertation on Virtue'' at the end of the Analogy). My difficulty was, as I have said, that this claim of conscience, whether utilitarian or not, had to be harmonised with the claim of Rational Self-love; and that I vaguely supposed Butler to avoid or override [the latter claim].
But reading him at this stage with more care, I found in him, with pleasure and surprise, a view very similar to that which had developed itself in my own mind in struggling to assimilate Mill and Kant. I found he expressly admitted that ``interest, my own happiness, is a manifest obligation'', and that ``Reasonable Self-love'' [is ``one of the two chief or superior principles in the nature of man'']. That is, he recognised a ``Dualism of the Governing Faculty''---or as I prefer to say ``Dualism of the Practical Reason'', since the `authority' on which Butler laid stress must present itself to my mind as the authority of reason, before I can admit it.
Of this more presently: what I now wish to make clear is that it was on this side---if I may so say---that I entered into Butler's system and came under the influence of his powerful and cautious intellect. But the effect of his influence carried me a further step away from Mill: for I was led by it to abandon the doctrine of Psychological Hedonism, and to recognise the existence of `disinterested' or `extra-regarding' impulses to action, [impulses] not directed towards the agent's pleasure [cf. chap iv. of Book i. of The Methods of Ethics]. In fact as regards what I may call. a Psychological basis of Ethics, I found myself much more in agreement with Butler than Mill.
And this led me to reconsider my relation to Intuitional Ethics. The strength and vehemence of Butler's condemnation of pure Utilitarianism, in so cautious a writer, naturally impressed me much. And I had myself become, as I had to admit to myself, an Intuitionist to a certain extent. For the supreme rule of aiming at the general happiness, as I had come to see, must rest on a fundamental moral intuition, if I was to recognise it as binding at all. And in reading the writings of the earlier English Intuitionists, More and Clarke, I found the axiom I required for my Utilitarianism [That a rational agent is bound to aim at Universal Happiness], in one form or another, holding a prominent place (cf. History of Ethics, pp. 172, 181).
I had then, theoretically as well as practically, accepted this fundamental moral intuition; and there was also the Kantian principle, which I recognised as irresistibly valid, though not adequate to give complete guidance.---I was then an ``intuitional'' moralist to this extent: and if so, why not further? The orthodox moralists such as Whewell (then in vogue) said that there was a whole intelligible system of intuitions: but how were they to be learnt? 1 could not accept Butler's view as to the sufficiency of a plain man's conscience: for it appeared to me that plain men agreed rather verbally than really.
In this state of mind I had to read Aristotle again; and a light seemed to dawn upon me as to the meaning and drift of his procedure---especially in Books ii., iii., iv. of the Ethics---(cf. History of Ethics, chap. ii. §9, p. 58, read to end of section).
What he gave us there was the Common Sense Morality of Greece, reduced to consistency by careful comparison: given not as something external to him but as what ``we''---he and others---think, ascertained by reflection. And was not this really the Socratic induction, elicited by interrogation? Might I not imitate this: do the same for our morality here and now, in the same manner of impartial reflection on current opinion?
Indeed ought I not to do this before deciding on the question whether I had or had not a system of moral intuitions? At any rate the result would be useful, whatever conclusion I came to.
So this was the part of my book first written (Book iii., chaps. i--xi.), and a certain imitation of Aristotle's manner was very marked in it at first, and though I have tried to remove it where it seemed to me affected or pedantic, it still remains to some extent.
But the result of the examination was to bring out with fresh force and vividness the difference between the maxims of Common Sense Morality (even the strongest and strictest, e.g. Veracity and Good Faith) and the intuitions which I had already attained, i.e. the Kantian Principle (of which I now saw the only certain element in Justice---``treat similar cases similarly''---to be a particular application), and the Fundamental Principle of Utilitarianism. And this latter was in perfect harmony with the Kantian Principle. I certainly could will it to be a universal law that men should act in such a way as to promote universal happiness; in fact it was the only law that it was perfectly clear to me that I could thus decisively will, from a universal point of view.
I was then a Utilitarian again, but on an Intuitional basis.
But further, the reflection on Common Sense Morality which I had gone through, had continually brought home to me its character as a system of rules tending to the promotion of general happiness (cf. [Methods of Ethics] pp. 470, 471).
Also the previous reflection on hedonistic method for Book ii. had shown me its weaknesses. What was then to be done? [The] conservative attitude [to be observed] towards Common Sense [is] given in chapter v. of Book iv.: ``Adhere generally, deviate and attempt reform only in exceptional cases in which,---notwithstanding the roughness of hedonistic method,---the argument against Common Sense is decisive.''
In this state of mind I published my book: I tried to say what I had found: that the opposition between Utilitarianism and Intuitionism was due to a misunderstanding. There was indeed a fundamental opposition between the individual's interest and either morality, which I could not solve by any method I had yet found trustworthy, without the assumption of the moral government of the world: so far I agreed with both Butler and Kant.
But I could find no real opposition between Intuitionism and Utilitarianism The Utilitarianism of Mill and Bentham seemed to me to want a basis: that basis could only be supplied by a fundamental intuition; on the other hand the best examination 1 could make of the Morality of Common Sense showed me no clear and self-evident principles except such as were perfectly consistent with Utilitarianism.
Still, investigation of the Utilitarian method led me to see defects [in it]: the merely empirical examination of the consequences of actions is unsatisfactory, and being thus conscious of the practical imperfection in many cases of the guidance of the Utilitarian calculus, I remained anxious to treat with respect, and make use of, the guidance afforded by Common Sense in these cases, on the ground of the general presumption which evolution afforded that moral sentiments and opinions would point to conduct conducive to general happiness; though I could not admit this presumption as a ground for overruling a strong probability of the opposite, derived from utilitarian calculations.''
It only remains to mention that the Table of Contents and the Index have been revised in accordance with the changes in the text.
CAMBRIDGE, April 1901.