The same is true of the other forms in which Mill expresses the conception on which he considers the proof of Utilitarianism to rest. Desiring a thing and finding it pleasant … are two parts of the same phenomenon. To think of an object as desirable … and to think of it as pleasant are one and the same thing. Both statements are ambiguous. Each is in a sense true, but not in the sense which would imply that a pleasure is the only possible object of desire. In the latter statement, what is meant by thinking of an object as desirable? Does it mean thinking of it as one that should be desired? Thus understood, the statement would lose all plausibility. No one would pretend to think of an object as one which he should desire is the same thing as thinking of it as pleasant. Rather, so long as he thinks of it as one in which he finds pleasure, it is impossible for him to place it in any such relation to himself as could be represented by saying that he thinks of it as an object which he should desire. Nor is there any sign that Mill uses the terms desired and desirable except as pretty much equivalent. To think of an object as desirable means with him to reflect on it as one that is desired. Now it is quite true that I cannot reflect on an object as one that I desire without thinking of it as pleasant, in the sense that I cannot reflect on my desire for it without thinking of the pleasure there would be in the satisfaction of the desire. But this in no way implies that the desire is a desire for that or any other pleasure. (§168 ¶1)

As regards the other statement, if the phenomenon under consideration is taken to include both the desire for an object and the satisfaction of that desire in the attainment of its object, then to desire the object and to find its attainment pleasant are doubtless parts of that one phenomenon. If, on the other hand, the phenomenon is held to be confined to the desire, and not to include its satisfaction, then to find a thing pleasant is no part of the phenomenon; for unsatisfied desire involves no pleasure. We may suppose, however, that to find it pleasant is here hastily written for to anticipate pleasure from it. Thus interpreted, the statement is indisputable so far as it goes. To desire an object, and to anticipate pleasure from its attainment, are certainly parts of one and the same phenomenon. But the question remains of the relation in which the two parts of the phenomenon stand to each other. Is it always the anticipation of pleasure from an object that excites the desire for it, or are there cases in which the anticipation of pleasure in the satisfaction of desire arises out of an independent desire for an object which is not pleasure at all? The former is the view which Mill believed himself to hold, and which his Proof of Utilitarianism requires; but the proposition under consideration is equally compatible with the latter view, and it may be doubted whether it would have seemed so self-evident to most readers, or even to Mill himself, if it were not so. (§168 ¶2)