The moral idea, then, which I propose to discuss, is the idea of duty or moral obligation, or, what comes to the same thing, the idea of what is wrong—morally wrong. Everybody would agree that this idea—or, to speak more accurately, one or both of these two ideas—is among the most fundamental of our moral ideas, whether or not they would admit that all others, for example the ideas of moral goodness, involve a reference to this one in their definition, or would hold that we have some others which are independent of it, and equally fundamental with it.
But there is a good deal of difficulty in getting clear as to what this idea of moral obligation itself is. Is there in fact only one idea which we call by this name? Or is it possible that on some occasions when we say that so and so is a duty, we mean something different by this expression from what we do on others? And that similarly when we say that so and so is morally wrong, we sometimes use this name "morally wrong" for one idea and sometimes for another; so that one and the same thing may be "morally wrong" in one sense of the word, and yet not morally wrong in another? I think, in fact, there are two different senses in which we use these terms; and to point out the difference between them, will help to bring out clearly more the nature of each. And I think perhaps the difference can be brought out most clearly by considering the sort of moral rules with which we are all of us familiar.
Everybody knows that moral teachers are largely concerned in laying down moral rules, and in disputing the truth of rules which have been previously accepted. And moral rules seem to consist, to a very large extent, in assertions to the effect that it is always wrong to do certain actions or to refrain from doing certain others; or (what comes to the same thing) that it is always your duty to refrain from certain actions, and positively to do certain others. The Ten Commandments for example, are instances of moral rules; and most of them are examples of what are called negative rules—that is to say rules which assert merely that it is wrong to do certain positive actions, and therefore our duty to refrain from these actions; instead of rules which assert of certain positive actions, that it is our duty to do them and therefore wrong to refrain from doing them. The fifth commandment, which tells us to honour our father and mother, is apparently an exception; it seems to be a positive rule. It is not, like the others, expressed in the negative form "Thou shalt not do so and so," and it is apparently really meant to assert that we ought to do certain positive actions, not merely that there are some positive action from which we ought to refrain. The difference between this one and the rest will thus serve as an example of the difference between positive and negative moral rules, a difference which is sometimes treated as if it were of great importance. And I do not wish to deny that there may be some important difference between seeing only that certain positive actions are wrong, and seeing also that, in certain cases, to refrain from doing certain actions is just as wrong as positively to do certain others. But this distinction between positive and negative rules is certainly of much less importance than another which is, I think, liable to be confused with it. So far as this distinction goes it is only a distinction between an assertion that it is wrong to do a positive action and an assertion that it is wrong to refrain from doing one: and each of these assertions is equivalent to one which asserts a duty—the first with an assertion that it is a duty to refrain, the second with an assertion that a positive action is a duty. But there is another distinction between some moral rules and others, which is of much greater importance than this one, and which does, I think, give a reason for thinking that the term "moral obligation" is actually used in different senses on different occasions.
I have said that moral rules seem to consist, to a large extent, in assertions to the effect that it is always wrong to do certain actions or to refrain from doing certain others, or the equivalent assertions in terms of duty. But there is a large class of moral rules, with which we are all of us very familiar, which do not come under this definition. They are rules which are concerned not with our actions, in the natural sense of the word, but with our feelings, thoughts and desires. An illustration of this kind of rule can again be given from the Ten Commandments. Most of the ten, as we all know, are concerned merely with actions; but the tenth at least is clearly an exception. The tenth says "Thou shalt not covet thy neighbour's house, nor his wife, nor his servant, nor his ox, nor his ass, nor anything that is his," and, unless "covet" is merely a mistranslation of a word which stands for some kind of action, we plainly have here a rule which is concerned with our feelings and not with our actions. And one reason which makes the distinction between rules of this kind and rules concerned with actions important, is that our feelings are not, as a rule, directly within the control of our will in the sense in which many of our actions are. I cannot, for instance, by any single act of will directly prevent from arising in my mind a desire for something that belongs to some one else, even if, when once the desire has arrived, I can by my will prevent its continuance; and even this last I can hardly do directly but only by forcing myself to attend to other considerations which may extinguish the desire. But though I thus cannot prevent myself altogether from coveting my neighbour's possessions, I can altogether prevent myself from stealing them. The action of stealing, and the feeling of covetousness, are clearly on a very different level in this respect. The action is directly within the control of my will, whereas the feeling is not. If I will not to take the thing (though of course some people may find a great difficulty in willing this) it does in general follow directly that I do not take it; whereas, it I will not to desire it, it emphatically does not, even in general, follow directly that no desire for it will be there. This distinction between the way in which our feelings and our actions are under the control of our wills is, I think, a very real one indeed; we cannot help constantly recognising that it exists. And it has an important bearing on the distinction between those moral rules which deal with actions and those which deal with feelings, for the following reason. The philosopher Kant laid down a well-known proposition to the effect that "ought" implies "can": that is to say, that it cannot be true that you "ought" to do a thing, unless it is true that you could do it, if you chose. And as regards one of the senses in which we commonly use the words "ought" and "duty," I think this rule is plainly true. When we say absolutely of ourselves or others, "I ought to do so and so" or "you ought to," we imply, I think, very often that the thing in question is a thing which we could do, if we chose; though of course it may often be a thing which it is very difficult to choose to do. Thus it is clear that I cannot truly say of anyone that he ought to do a certain thing, if it is a thing which it is physically impossible for him to do, however desirable it may be that the thing should be done. And in this sense it is clear that it cannot be truly said of me that I ought not to have a certain feeling, or that I ought not to have had it, if it is a feeling which I could not, by any effort of my will, prevent myself from having. The having or the prevention of a certain feeling is not, of course, strictly ever a physical impossibility, but it is very often impossible, in exactly the same sense, in which actions are physically impossible—that is to say that I could not possibly get it or prevent it, even if I would. But this being so, it is plain that such a moral rule as that I ought not to covet my neighbour's possessions is, if it means to assert that I ought not, in that sense in which "ought" implies "can," a rule which cannot possibly be true. What it appears to assert is, absolutely universally, of every feeling of covetousness, that the feeling in question is one which the person who felt it ought not to have felt. But in fact a very large proportion of such feelings (I am inclined to say the vast majority) are feelings which the person who felt them could not have prevented feeling, if he would: they were beyond the control of his will. And hence it is quite emphatically not true that none of these feelings ought to have been felt, if we are using "ought" in the sense which implies that the person who felt them could have avoided them. So far from its being true that absolutely none of them ought to have been felt, this is only true of those among them, probably a small minority, which the person who felt them could have avoided feeling. If, therefore, moral rules with regard to feelings are to have a chance of being nearly true, we must understand the "ought" which occurs in them in some other sense. But with moral rules that refer to actions the case is very different. Take stealing for example. Here again what the Eighth Commandment appears to imply is that absolutely every theft which has ever occurred was an act which the agent ought not to have done; and, if the "ought" is the one which implies "can," it implies, therefore, that every theft was an act which the agent, if he had chosen, could have avoided. And this statement that every theft which has been committed was an act which the thief, if he had so willed, could have avoided, though it may be doubted if it is absolutely universally true, is not a statement which is clearly absurd, like the statement that every covetous desire could have been avoided by the will of the person who felt it. It is probable that the vast majority of acts of theft have been acts which it was in the power of the thief to avoid, if he had willed to do so; whereas this is clearly not true of the vast majority of covetous desires. It is, therefore, quite possible that those who believe we ought never to steal are using "ought" in a sense which implies that stealing always could have been avoided; whereas it is I think quite certain that many of those who believe that we ought to avoid all covetous desires, do not believe for a moment that every covetous desire that has ever been felt was a desire which the person who felt it could have avoided feeling, if he had chosen. And yet they certainly do believe, in some sense or other, that no covetous desire ought ever to have been felt. The conclusion is, therefore, it seems to me, unavoidable that we do use "ought," the moral "ought," in two different senses; the one a sense in which to say that I ought to have done so and so does really imply that I could have done it, if I had chosen, and the other a sense in which it carries with it no such implication. I think perhaps the difference between the two can be expressed in this way. If we express the meaning of the first "ought," the one which does imply "can," by saying that "I ought to have done so and so" means "It actually was my duty to do it"; we can express the meaning of the second by saying that e.g. "I ought not to have felt so and so" means not "it was my duty to avoid that feeling," but "it would have been my duty to avoid it, if I had been able." And corresponding to these two meanings of "ought" we should, I think, probably distinguish two different sorts of moral rules, which though expressed in the same language, do in fact mean very different things. The one is a set of rules which assert (whether truly or falsely) that it always actually is a duty to do or to refrain from certain actions, and assert therefore that it always is in the power of the agent's will to do or to refrain from them; whereas the other sort only assert that so and so would be a duty, if it were within our power, without at all asserting that it always is within our power.
We may, perhaps, give a name to the distinction I mean, by calling the first kind of rules—those which do assert that something actually is a duty—"rules of duty," and by calling the second kind—those which recommend or condemn something not in the control of our wills—"ideal rules": choosing this latter name because they can be said to inculcate a moral "ideal"—something the attainment of which is not directly within the power of our wills. As a further example of the difference between ideal rules and rules of duty we may take the famous passage from the New Testament (Luke 6, 27) "Love your enemies, do good to them that hate you, bless them that curse you, pray for them that despitefully use you." Of these four rules, the three last may be rules of duty, because they refer to things which are plainly, as a rule, at least, in the power of your will; but the first, if "love" be understood in its natural sense as referring to your feelings, is plainly only an "ideal" rule, since such feelings are obviously not directly under our own control, in the same way in which such actions as doing good to, blessing or praying for a person are so. To love certain people, or to feel no anger against them, is a thing which it is quite impossible to attain directly by will, or perhaps ever to attain completely at all. Whereas your behaviour towards them is a matter within your own control: even if you hate a person, or feel angry with him, you can so control yourself as not to do him harm, and even to confer benefits upon him. To do good to your enemies may, then, really be your duty; but it cannot, in the strict sense, be your duty not to have evil feelings towards them: all that can possibly be true is that it would be your duty if you were able. Yet I think there can be no doubt that what Christ meant to condemn was the occurrence of such feelings altogether; and since, if what he meant to assert about them in condemning them, would have been certainly false, if he had meant to say that you could avoid ever feeling them, I think it is clear that what he meant to assert was not this, or not this only, but something else, which may quite possibly be true. That is to say, he was asserting an ideal rule, not merely a rule of duty.
It will be seen that this distinction which I am making coincides, roughly at all events, with the distinction which is often expressed as the distinction between rules which tell you what you ought to be and rules which tell you merely what you ought to do; or as the distinction between rules which are concerned with your inner life—with your thoughts and feelings—and those which are concerned only with your external actions. The rules which are concerned with what you ought to be or with your inner life are, for the most part at all events, "ideal" rules; while those which are concerned with what you ought to do or your external actions are very often, at least, rules of duty. And it is often said that one great difference between the New Testament and the Old is its comparatively greater insistence on "ideal" rules—upon a change of heart—as opposed to mere rules of duty. And that there is a comparatively greater insistence on ideal rules I do not wish to deny. But that there are plenty of ideal rules in the Old Testament too must not be forgotten. I have already given an example from the Ten Commandments: namely the rule which says you ought not to covet anything which belongs to your neighbour. And another is supplied by the Old Testament commandment, "Love thy neighbour as thyself," if by "love" is here meant a feeling which is not within our own control, and not merely that the Jew is to help other Jews by his external actions. Indeed, however great may be the difference between the Old Testament and the New in respect of comparative insistence on ideal rules rather than rules of duty, I am inclined to think that there is at least as great a difference, illustrated by this very rule, in another, quite different, respect—namely in the kind of rules, both ideal and of duty, which are insisted on. For whereas by "thy neighbour" in the Old Testament there is plainly meant only other Jews, and it is not conceived either that it is the duty of a Jew to help foreigners in general, or an ideal for him to love them; in the New Testament, where the same words are used, "my neighbour" plainly is meant to include all mankind. And this distinction between the view that beneficent action and benevolent feelings should be confined to those of our own nation, and the view that both should be extended equally to all mankind,—a distinction which has nothing to do with the distinction between being and doing, between inner and outer, but affects both equally—is, I am inclined to think, at least as important a difference between New Testament and Old, as the comparatively greater insistence on "ideal" rules. However, the point upon which I want at present to insist is the distinction between ideal rules and rules of duty. Both kinds are commonly included among moral rules, and, as my examples have shown, are often mentioned together as if no great difference were seen between them. What I want to insist on is that there is a great difference between them: that whereas rules of duty do directly assert of the idea of duty, in the sense in which to say that something is your duty implies that you can do it, that certain things are duties, the "ideal" rules do not assert this, but something different. Yet the "ideal" rules certainly do, in a sense, assert a "moral obligation." And hence we have to recognise that the phrase "moral obligation" is not merely a name for one idea only, but for two very different ideas; and the same will, of course, be true of the corresponding phrase "morally wrong."
When, therefore, I say that the idea of "moral obligation" is one of the fundamental ideas with which Moral Philosophy is concerned, I think we must admit that this one name really stands for two different ideas. But it does not matter for my purpose which of the two you take. Each of them is undoubtedly a moral idea, and whatever answer be given to the question we are going to raise about the one, will also certainly apply to the other.
But it is now time to turn to the other idea, with which I said that Moral Philosophy has been largely concerned, though it is not, strictly speaking, a moral idea, at all.
And I think, perhaps, a good way of bringing out what this idea is, is to refer to the Ethics of Aristotle. Everybody would admit that the fundamental idea, with which Aristotle's Ethics is concerned, is an idea which it is the business of Moral Philosophy to discuss; and yet I think it is quite plain that this idea is not a moral idea at all. Aristotle does not set out from' the idea of moral obligation or duty (indeed throughout his treatise he only mentions this idea quite incidentally); nor even from the idea of moral goodness or moral excellence, though he has a good deal more to say about that; but from the idea of what he calls "the human good," or "good for man." He starts by raising the question what the good for man is, and his whole book is arranged in the form of giving a detailed answer to that question. And I think we can gather pretty well what the idea is, which he calls by this name, by considering what he says about it. There are two points, in particular, which he insists upon from the outset: first, that nothing can be good, in the sense he means, unless it is something which is worth having for its own sake, and not merely for the sake of something else; it must be good in itself; it must not, like wealth (to use one example which he gives) be worth having merely for the sake of what you can do with it; it must be a thing which is worth having even if nothing further comes of it. And secondly (what partly covers the former, but also, I think, says something more) it must, he says, be something that is "self-sufficient": something which, even if you had nothing else would make your life worth having. And further light is thrown upon his meaning when he comes to tell you what he thinks the good for man is: the good, he says, is "mental, activity—where such activity is of an excellent kind, or, if there are several different kinds of excellent mental activity, that which has the best and most perfect kind of excellence; and also" (he significantly adds) "mental activity which lasts through a sufficiently long life." The word which I have here translated "excellence" is what is commonly translated "virtue"; but it does not mean quite the same as we mean by "virtue," and that in a very important respect. "Virtue" has come to mean exclusively moral excellence; and if that were all Aristotle meant, you might think that what he means by "good" came very near being a moral idea. But it turns out that he includes among "excellences," intellectual excellence, and even that he thinks that the best and most perfect excellence of which he speaks is a particular kind of intellectual excellence, which no one would think of calling a moral quality, namely, the sort of excellence which makes a man a good philosopher. And as for the word which I have translated "activity," the meaning of this can be best brought out by mentioning the reason which Aristotle himself gives for saying that mere excellence itself is not (as some of the Greeks had said) the good for man. He says, truly enough, that a man may possess the greatest excellence—he may be a very excellent man—even when he is asleep, or is doing nothing; and he points out that the possession of excellence when you are asleep is not a thing that is desirable for its own sake—obviously only for the sake of the effects it may produce when you wake up. It is not therefore, he thinks, mere mental excellence, but the active exercise of mental excellence—the state of a man's mind, when he not only possesses excellent faculties, moral or intellectual, but is actively engaged in using them, which really constitutes the human good.