§7. If, then, the prescriptions of Justice, Good Faith, and Veracity, as laid down by Common Sense, appear so little capable of being converted into first principles of scientific Ethics, it seems scarcely necessary to inquire whether such axioms can be extracted from minor maxims of social behaviour, such as the maxim of Liberality or the rules restraining the Malevolent Affections: or, again, from such virtues as Courage and Humility, which we found it difficult to class as either social or self-regarding. Indeed, it was made plain in chap. viii. that as regards the proper regulation of resentment, Common Sense can only be saved from inconsistency or hopeless vagueness by adopting the `interest of society' as the ultimate standard: and in the same way we cannot definitely distinguish Courage from Foolhardiness except by a reference to the probable tendency of the daring act to promote the wellbeing of the agent or of others, or to some definite rule of duty prescribed under some other notion.
It is true that among what are commonly called ``duties to self'' we find the duty of self-preservation prescribed with apparent absoluteness,---at least so far as the sacrifice of one's life is not imperatively required for the preservation of the lives of others, or for the attainment of some result conceived to be very important to society. I think, however, that when confronted with the question of preserving a life which we can foresee will be both miserable and burdensome to others---e.g. the life of a man stricken with a fatal disease which precludes the possibility of work of any kind, during the weeks or months of agony that remain to him,---though Common Sense would still deny the legitimacy of suicide, even under these conditions, it would also admit the necessity of finding reasons for the denial. This admission would imply that the universal wrongness of suicide is at any rate not self-evident. And the reasons that would be found so far as they did not ultimately depend upon premises drawn from Revelational Theology---would, I think, turn out to be utilitarian, in a broad sense of the term: it would be urged that if any exceptions to the rule prohibiting suicide were allowed, dangerous encouragement would be given to the suicidal impulse in other cases in which suicide would really be a weak and cowardly dereliction of social duty: it would also probably be urged that the toleration of suicide would facilitate secret murders. In short, the independent axiom of which we are in search seems to disappear on close examination in this case no less than in others.
So again, reflection seems to show that the duties of Temperance, Self-control, and other cognate virtues, are only clear and definite in so far as they are conceived as subordinate either to Prudence (as is ordinarily the case), or to Benevolence or some definite rule of social duty, or at least to some end such as `furtherance of moral progress'---of which the conception involves the notion of duty supposed to be already determinate. Certainly the authority of Common Sense cannot be fairly claimed for any restriction even of the bodily appetites for food and drink, that is not thus subordinated.
In the case, however, of the sexual appetite, a special regulation seems to be prescribed on some independent principle under the notion of Purity or Chastity. In chap. ix. of this Book, where we examined this notion, it appeared that Common Sense is not only not explicit, but actually averse to explicitness, on this subject. As my aim in the preceding chapters was to give, above all things, a faithful exposition of the morality of Common Sense, I allowed my inquiry to be checked by this (as it seemed) clearly recognisable sentiment. But when it becomes our primary object to test the intuitive evidence of the moral principles commonly accepted, it seems necessary to override this aversion: for we can hardly ascertain whether rational conviction is attainable as to the acts allowed and forbidden under this notion and its opposite, without subjecting it to the same close scrutiny that we have endeavoured to give to the other leading notions of Ethics. Here the briefest account of such a scrutiny will be sufficient. I am aware that in giving even this I cannot but cause a certain offence to minds trained in good moral habits: but I trust I may claim the same indulgence as is commonly granted to the physiologist, who also has to direct the student's attention to objects which a healthy mind is naturally disinclined to contemplate.