Now, we are struck by the fact that this affirmation of the universal validity of the principle of truth is made in a chapter on "Cases of Conscience," in a chapter concerned with what seem to be conflicts between duties; and this chapter is followed by one which treats of "Cases of Necessity," _i.e._ cases in which a man is to be regarded as justified in violating common rules when there seems to be urgent reason for so doing. We are told that the moralist cannot say: Lie not, except in great emergencies; but must say: Lie not at all. But we are also told that he must grant that there are cases of necessity in which transgressions of moral rules are excusable; and this looks very much as if he said: Go on and do the thing while I close my eyes. This hardly seems to give us a "sure and connected knowledge of the duties of man" deduced from axiomatic principles. On what authority shall we suspend for the time being this axiomatic principle or that? Is there some deeper principle which lends to each of them its authority, and which may, for cause, withdraw it? There is no hint of such in the treatment of ethics which we are considering, and we seem to have on our hands, not so much a science, as a collection of practical rules, of the scope of which we are more or less in the dark. The interesting thing to notice is that this view of ethics is very closely akin to that adapted unconsciously by the majority of the persons we meet who have not interested themselves much in ethics as a science. By the time that we have reached years of discretion we are all in possession of a considerable number of moral maxims. We consider it wrong to steal, to lie, to injure our neighbor. Such maxims lie in our minds side by side, and we do not commonly think of criticising them. But now and then we face a situation in which one maxim seems to urge one course of action and another maxim a contrary one. Shall we tell the truth and the whole truth, when so doing will bring grave misfortune upon an innocent person? And now and then we are brought to the realization that all men do not admit the validity of all our maxims. Judgments differ as to what is right and what is wrong. Who shall be the arbiter? Not infrequently a rough decision is arrived at in the assumption that we have only to interrogate "conscience"--in the assumption, in other words, that we carry a watch which can be counted upon to give the correct time, even if the timepieces of our neighbors are not to be depended upon. The common sense ethics cannot be regarded as very systematic and consistent, or as very profound. It is a collection of working rules, of practical maxims; and, although it is impossible to overestimate its value as a guide to life, its deficiencies, when it is looked at critically, become evident, I think, even to thoughtful persons who are not scientific at all.