Probably there is no antithesis more often set up in moral discussion than that between acting from 'principle' and from 'interest.' To act on principle is to act disinterestedly, according to a general law, which is above all personal considerations. To act according to interest is, so the allegation rums, to act selfishly, with one's own personal profit in view. It substitutes the changing expediency of the moment for devotion to unswerving moral law. The false idea of interest underlying this opposition has already been criticized (See Chapter X), but some moral aspects of the question will now be considered.

A clew to the matter may be found in the fact that the supporters of the 'interest' side of the controversy habitually use the term 'self-interest.' Starting from the premisses that unless there is interest in an object or idea, there is no motive force, they end with the conclusion that even when a person claims to be acting from principle or from a sense of duty, he really acts as he does because there 'is something in it' for himself. The premiss is sound; the conclusion false. In reply the other school argues that since man is capable of generous self-forgetting and even self-sacrificing action, he is capable of acting without interest. Again the premiss is sound, and the conclusion false. The error on both sides lies in a false notion of the relation of interest and the self.

Both sides assume that the self is a fixed and hence isolated quantity. As a consequence, there is a rigid dilemma between acting for an interest of the self and without interest. If the self is something fixed antecedent to action, then acting from interest means trying to get more in the way of possessions for the self—whether in the way of fame, approval of others, power over others, pecuniary profit, or pleasure. Then the reaction from this view as a cynical depreciation of human nature leads to the view that men who act nobly act with no interest at all. Yet to an unbiased judgment it would appear plain that a man must be interested in what he is doing or he would not do it. A physician who continues to serve the sick in a plague at almost certain danger to his own life must be interested in the efficient performance of his profession—more interested in that than in the safety of his own bodily life. But it is distorting facts to say that this interest is merely a mask for an interest in something else which he gets by continuing his customary services—such as money or good repute or virtue; that it is only a means to an ulterior selfish end. The moment we recognize that the self is not something ready-made, but something in continuous formation through choice of action, the whole situation clears up. A man's interest in keeping at his work in spite of danger to life means that his self is found in that work; if he finally gave up, and preferred his personal safety or comfort, it would mean that he preferred to be that kind of a self. The mistake lies in making a separation between interest and self, and supposing that the latter is the end to which interest in objects and acts and others is a mere means. In fact, self and interest are two names for the same fact; the kind and amount of interest actively taken in a thing reveals and measures the quality of selfhood which exists. Bear in mind that interest means the active or moving identity of the self with a certain object, and the whole alleged dilemma falls to the ground.

Unselfishness, for example, signifies neither lack of interest in what is done (that would mean only machine-like indifference) nor selflessness—which would mean absence of virility and character. As employed everywhere outside of this particular theoretical controversy, the term 'unselfishness' refers to the kind of aims and objects which habitually interest a man. And if we make a mental survey of the kind of interests which evoke the use of this epithet, we shall see that they have two intimately associated features. (i) The generous self consciously identifies itself with the full range of relationships implied in its activity, instead of drawing a sharp line between itself and considerations which are excluded as alien or indifferent; (ii) it readjusts and expands its past ideas of itself to take in new consequences as they become perceptible. When the physician began his career he may not have thought of a pestilence; he may not have consciously identified himself with service under such conditions. But, if he has a normally growing or active self, when he finds that his vocation involves such risks, he willingly adopts them as integral portions of his activity. The wider or larger self which means inclusion instead of denial of relationships is identical with a self which enlarges in order to assume previously unforeseen ties.

In such crises of readjustment—and the crisis may be slight as well as great—there may be a transitional conflict of 'principle' with 'interest.' It is the nature of a habit to involve ease in the accustomed line of activity. It is the nature of a readjusting of habit to involve an effort which is disagreeable—something to which a man has deliberately to hold himself. In other words, there is a tendency to identify the self—or take interest—in what one has got used to, and to turn away the mind with aversion or irritation when an unexpected thing which involves an unpleasant modification of habit comes up. Since in the past one has done one's duty without having to face such a disagreeable circumstance, why not go on as one has been? To yield to this temptation means to narrow and isolate the thought of the self—to treat it as complete. Any habit, no matter how efficient in the past, which has become set, may at any time bring this temptation with it. To act from principle in such an emergency is not to act on some abstract principle, or duty at large; it is to act upon the principle of a course of action, instead of upon the circumstances which have attended it. The principle of a physician's conduct is its animating aim and spirit—the care for the diseased. The principle is not what justifies an activity, for the principle is but another name for the continuity of the activity. If the activity as manifested in its consequences is undesirable, to act upon principle is to accentuate its evil. And a man who prides himself upon acting upon principle is likely to be a man who insists upon having his own way without learning from experience what is the better way. He fancies that some abstract principle justifies his course of action without recognizing that his principle needs justification.

Assuming, however, that school conditions are such as to provide desirable occupations, it is interest in the occupation as a whole—that is, in its continuous development—which keeps a pupil at his work in spite of temporary diversions and unpleasant obstacles. Where there is no activity having a growing significance, appeal to principle is either purely verbal, or a form of obstinate pride or an appeal to extraneous considerations clothed with a dignified title. Undoubtedly there are junctures where momentary interest ceases and attention flags, and where reënforcement is needed. But what carries a person over these hard stretches is not loyalty to duty in the abstract, but interest in his occupation. Duties are 'offices'—they are the specific acts needed for the fulfilling of a function—or, in homely language, doing one's job. And the man who is genuinely interested in his job is the man who is able to stand temporary discouragement, to persist in the face of obstacles, to take the lean with the fat: he makes an interest out of meeting and overcoming difficulties and distractions.