How Hume gives meaning to this otherwise unmeaning definition: ‘Interest,’ like other motives described, implies determination by reason.
47. Such desire, then, being excluded, what other motive than ‘interest’ remains, by contrast with which the latter may be defined? It has been explained above (§7) that since pleasure as such, or as a feeling, does not admit of generality, ‘pleasure in general’ is an impossible object. When the motive of an action is said to be ‘pleasure in general,’ what is really meant is that the action is determined by the conception of pleasure, or, more properly, of self as a subject to be pleased. Such determination, again, is distinguished by opposition to two other kinds—(a) to that sort of determination which is not by conception, but either by animal want, or by the animal imagination of pleasure, and (b) to determination by the conception of other objects than pleasure. By an author, however, who expressly excluded the latter sort of determination, and who did not recognise any distinction between the thinking and the animal subject, the motive in question could not thus be defined. Hence the difficulty of extracting from Hume himself any clear and consistent account of that which he variously describes as the ‘general appetite for good, considered merely as such,’ as ‘interest,’ and as ‘self-love.’ To say that he understood by it a desire for pleasure which is yet not a desire for any pleasure in particular, may seem a strange interpretation to put on one who regarded himself as a great liberator from abstractions, but there is no other which his statements, taken together, would justify. This desire for nothing, however, he converts into a desire for something by identifying it on occasion, (1) with any desire for a pleasure of which the attainment is regarded as sufficiently remote to allow of calmness in the desire, and (2) with desire for the means of having all pleasures indifferently at command. It is in one or other of these senses—either as desire for some particular pleasure distinguished only by its calmness, or as desire for power—that he always understands ‘interest’ or ‘self-love,’ except where he gains a more precise meaning for it by the admission of desires, not for pleasure at all, to which it may be opposed. Now taken in the former sense, its difference from the desires for the several pleasures of ‘sense,’ ‘pride,’ and ‘sympathy,’ of which Hume’s account has already been examined, cannot lie in the object, but—as he himself says of the distinction, which he regarded as an equivalent one, between ‘reasonable and unreasonable’ desires—in our situation with regard to it. If then the object of each of these desires, as we have shown to be implied in Hume’s account of them, is one which only reason, as self-consciousness, can constitute, it cannot be less so when the desire is calm enough to be called self-love. Still more plainly is the desire in question determined by reason—by the conception of self as a permanent susceptibility of pleasure—if it is understood to be desire for power.
Thus Hume, having degraded morality for the sake of consistency, after all is not consistent.
48. Having now before us a complete view of the possible motives to human action which Hume admits, we find that while he has carried to its furthest limit, and with the least verbal inconsistency possible, the effort to make thought deny its own originativeness in action, he has yet not succeeded. He has made abstraction of everything in the objects of human interest but their relation to our nervous irritability—he has left nothing of the beautiful in nature or art but that which it has in common with a sweetmeat, nothing of that which is lovely and of good report to the saint or statesman but what they share with the dandy or diner-out—yet he cannot present even this poor residuum of an object, by which all action is to be explained, except under the character it derives from the thinking soul, which looks before and after, and determines everything by relation to itself. Thus if, as he says, the distinction between reasonable and unreasonable desires does not lie in the object, this will not be because reason has never anything to do with the constitution of the object, but because it has always so much to do with it as renders selfishness—the self-conscious pursuit of pleasure—possible. Sensuality then will have been vindicated, the distinction between the ‘higher’ and ‘lower’ modes of life will have been erased, and after all the theoretic consistency—for the sake of which, and not, of course, to gratify any sinister interest, Hume made his philosophic venture—will not have been attained. Man will still not be ultimately passive, nor human action natural. Reason may be the ‘slave of the passions,’ but it will be a self-imposed subjection.
If all good is pleasure, what is moral good? Ambiguity in Locke’s view.
49. We have still, however, to explain how Hume himself completes the assimilation of the moral to the natural; how, on the supposition that the ‘good’ can only mean the ‘pleasant,’ he accounts for the apparent distinction between moral and other good, for the intrusion of the ‘ought and ought not’ of ethical propositions upon the ‘is and is not’ of truth concerning nature. [1] Here again he is faithful to his rôle as the expander and expurgator of Locke. With Locke, it will be remembered, the distinction of moral good lay in the channel through which the pleasure, that constitutes it, is derived. It was pleasure accruing through the intervention of law, as opposed to the operation of nature: and from the pleasure thus accruing the term ‘morally good’ was transferred to the act which, as ‘conformable to some law,’ occasions it. [2] This view Hume retains, merely remedying Locke’s omissions and inconsistencies. Locke, as we saw, not only neglected to derive the existence of the laws, whose intervention he counted necessary to constitute the morally good, from the operation of that desire for pleasure which he pronounced the only motive of man; in speaking of moral goodness as consisting in conformity to law, he might, if taken at his word, be held to admit something quite different from pleasure alike as the standard and the motive of morality. Hume then had, in the first place, to account for the laws in question, and so account for them as to remove that absolute opposition between them and the operation of nature which Locke had taken for granted; secondly, to exhibit that conformity to law, in which the moral goodness of an act was held to consist, as itself a mode of pleasure—pleasure, namely, to the contemplator of the act; and thirdly, to show that not the moral goodness of the act, even thus understood, but pleasure to himself was the motive to the doer of it. [3]
[1] Vol. II, p. 245. [Book III., part I., sec. I.]
[2] Above, secs. 16-18.
[3] Of the three problems here specified, Hume’s treatment of the second is discussed in the following secs. 50-54; of the first in secs. 55-58; of the third in secs. 60 to the end.
Development of it by Clarke, which breaks down for want of true view of reason.