The remainder of the argument will fall into two parts. On the basis of the psychology just expounded I shall try to show, in the first stage, how there must arise and persist for every self from its very nature, a contrast between two general 'ends,' one of which may be called the 'end of the self-as-such,' and the other (somewhat more loosely) the 'end of desire.' This, the simpler task, will not demand lengthy treatment. In the second stage I shall try to show that the 'end of the self-as-such' presents itself as 'obligatory' as against the 'end of desire' - that it wears the garb of the moral imperative. If this can be made good, then no more is required for the proof of the thesis which the chapter set out to maintain. It will have been shown that the recognition of an 'ought' is bound up with a form of experience which is fundamental and irremovable in human nature; wherefore the 'ought' must itself be accepted as fundamental and irremovable. The implications of such acceptance for metaphysics have been sufficiently dwelt upon.
Let us make a start, then, with the emergence of the contrast between the 'end of the self-as-such' and the 'end of desire'.
We have already seen how a being not merely immersed in the flow of its impulses, but capable of distinguishing itself from them, i.e. a self-conscious subject, will consider the objects of the impulses in the light of their capacity to satisfy the self This self-reference is what transforms rude animal impulse into the desire characteristic of rational beings. The 'mere object' of impulse becomes in desire 'object conceived as a good for the self'.
We have seen also how the 'self-referent' factor in desire has the effect of promoting a certain natural harmony in the several desires of the individual rational being (a feature which is absent from the mere impulsive material). The viewing (as in desire) of the object towards which an impulse is felt in the light of its capacity to satisfy the self raises the question of the object's compatibility or incompatibility with the other interests which the self is conscious of having, and this reflective consideration exercises a qualifying influence upon the original impulse, heightening or diminishing its force, according as its object is found to be in alignment with, or in opposition to, the interests of the self as a whole.
But we have also noticed in passing, and must now observe more closely, that this self-referent factor, although it operates naturally in the direction of harmony, does not of itself suffice to effect harmony. To consider the object of impulse in the light of its capacity to satisfy a self which is conscious of many other interests also claiming satisfaction involves the formulation of some conception as to the precise amount of indulgence (if any) which may be permitted consistently with the good of the self as a whole. It tells us what we should here desire, if our desire is to be in accord with what will best satisfy the self as the common subject of many desires. But this 'considering 'does not have the effect of producing in the desire, 'automatically' as it were, the precise adjustment whose fitness is conceptually clear. The conceived fullest or truest good of the self is often in opposition to the direction not merely of impulse, but of desire also. Desire is always for a conceived good of the self, as we have seen. The conceived good of the self may be something very different.
It will be helpful, perhaps, to see how these distinctions function in a concrete case. Let us suppose the case of a scientific explorer travelling alone through some desert waste. His store of water has by some mischance failed him, and, while still a day's journey from known supplies, he finds himself afflicted with a thirst that is almost unendurable. Suddenly he comes upon a wholly unexpected pool, and great is his elation until, on drawing closer to it, he finds unmistakable signs of pollution. He has not present, we shall suppose, the means of ascertaining the exact nature, and consequent danger, of the impurity, but he knows enough to be sure that there is at least grave risk in partaking.
Now let us consider the conative situation that may fairly be expected to arise here, from the point of view of the distinction of 'ends.' The dictate of impulse, per se, is to slake his thirst to the full. That is the first 'end.' But as a self-conscious subject he presents to himself the end of drinking the water in the light of its capacity to satisfy the self. And that self has many interests whose fulfilment, it is at once clear to him, will be seriously endangered if he allows even any indulgence to the impulse; and very much more seriously if he allows to the impulse completely full rein. For even slight indulgence, he sees, may mean death, either directly, or through such incapacitation as will unduly delay his reaching the near-by depot. Thus when he reviews the situation in the light of these manifold interests which drinking will endanger - his interest in bringing a difficult project, now all but achieved, to a satisfactory termination; his interest in collating and studying and circulating the valuable scientific data that he has amassed; the interests that affect him as husband, parent, and friend; his interest in new expeditions which he had promised himself for the future; his interest in mere living itself, or, what is perhaps the same thing, his aversion from the thought of physical death (to mention but a few of the more typical interests) - it is certain that he will regard it as really best for him that he should resist wholly the cravings of his parched throat and push on as rapidly as may be to the source of fresh supplies. Here then we have a second 'end,' the end representing the conceived good of the self-as-such, or of the self as the unity of its manifold interests. But there is a third end also. When the act of self-reference has taken place, and a conception thereby formed of what course of action is in accord with the good of the self as a whole, our traveller does not, unfortunately, find the 'set' of desire inclining straight to this good. Without a doubt the antagonism of impulse will have undergone modification through the self-reference which constitutes it as a 'desire.' It is improbable that he will 'desire' to drink unrestrainedly. Such an end is too crassly self-destructive to be even present to his mind once the act of self-reference has taken place. But almost certainly the modification will still leave a desire to drink - to drink perhaps just enough to relieve the first urgency of his distress. This is the third end, the 'end of desire,' and its presence as a factor opposed to the end of the self-as-such is manifested in the inner conflict which ensues. The traveller, if his thirst be as intense as we have hypothesized, will assuredly be conscious of having to exert will-power in order to achieve the 'end of the self-as-such.' He may, indeed, speak as if it were mere 'impulse,' his 'animal nature' which offers combat - 'flesh warring against spirit.' And this is in a sense true, since it is the power of the original 'animal impulse' continuing on, though in modified form, in desire, that is the ultimate source of the opposition. But strictly considered, that which offers the opposition must be named 'desire,' not' impulse.' Impulse has ceased to exist as such with the incidence of the act of self-reference.