To ground morality in utility is to make it entirely contingent and hypothetical. If actions are right because they promote happiness or social welfare, then moral obligation depends on consequences and circumstances, making the moral law variable and uncertain. But true moral obligation is categorical, not hypothetical. An action is right not because it produces good consequences but because it conforms to the categorical imperative—because it can be willed as universal law. Hume's utilitarianism, like all forms of consequentialism, makes morality dependent on empirical facts about what produces happiness, when in fact moral duty is determined a priori by practical reason. Justice, fidelity, and honesty are obligatory regardless of their utility.

Hume's emphasis on utility is sound as far as it goes, but it is not the complete story. Moral judgment involves not merely the assessment of utility but the operation of sympathy—our capacity to imaginatively enter into the situations and sentiments of others. We approve of virtuous actions not only because they are useful but because, through sympathy, we share in the pleasure they bring to those they benefit and in the approval of the impartial spectator. Utility is indeed important, but the moral sentiments operate through a more complex psychological mechanism than Hume's account suggests. The impartial spectator within us judges actions by their propriety and merit, not merely by their utility.

Hume here anticipates and provides foundation for the utilitarian principle that I would later develop systematically. He correctly identifies utility—the tendency to promote happiness and prevent misery—as the ground of moral approval. However, his account could be strengthened by distinguishing between act and rule utilitarianism, and by formulating the principle more precisely: actions are right in proportion as they tend to promote happiness, wrong as they tend to produce the reverse of happiness. Hume's emphasis on sentiment as the mechanism of moral judgment is also valuable. We approve of useful qualities not through cold calculation but through a sentiment of approbation that naturally arises when we contemplate beneficial actions.

Hume's utilitarianism represents the Enlightenment's attempt to ground morality in human nature and social utility after the collapse of the Aristotelian-Thomistic tradition. But by reducing virtue to whatever promotes utility, Hume empties the virtues of their traditional meanings and their connection to human flourishing conceived as the realization of our telos. The virtues in the classical tradition were not mere instruments for producing happiness but constituents of the good life. Courage, temperance, justice, and practical wisdom are not valuable merely because they happen to promote social utility, but because they are essential to the kind of life proper to rational animals. Hume's account is a degraded remnant of the virtue tradition it replaced.

Hume's account of justice as based purely on utility and convention is fundamentally mistaken. Justice is not a matter of social convention arising from utility, but a categorical duty grounded in respect for persons as rational agents. The principles of right—that we should honor contracts, respect property, refrain from fraud—are not justified by their social utility but by the demands of practical reason. We have duties of justice because persons have rights that must be respected regardless of consequences. To treat justice as merely a useful convention is to miss its moral necessity. Even if violating justice would produce greater overall happiness, it would still be wrong because it would violate the categorical imperative.

Hume is quite right that justice has its origin in considerations of utility—specifically, in the need to regulate property and prevent conflict under conditions of moderate scarcity. In a state of perfect abundance, justice would be unnecessary because everyone could have whatever they wanted. In a state of extreme scarcity, justice would be impossible because survival would require everyone to take whatever they could. Justice emerges in between these extremes as a set of conventions that serve our common interest in peaceful cooperation. However, once these conventions are established, we approve of just actions not merely because of their utility but because of their conformity to established rules that we have internalized through sympathy and education.

Hume's analysis of justice is penetrating and largely correct. Justice is indeed grounded in utility—specifically, in the utilities of security, stable expectations, and peaceful cooperation that rules of property make possible. These utilities are so fundamental that justice takes on the character of an absolute rule, and we feel strong sentiments of obligation toward it. However, we should recognize that rules of justice can conflict with utility in particular cases, and in such cases we may need to revise the rules or make exceptions. Justice is not merely about property but about rights generally, and rights are ultimately justified by the principle of utility properly understood—as concerned with the greatest happiness of the greatest number over the long term.

Hume's account of justice illustrates the bankruptcy of the Enlightenment project of grounding morality in human nature and utility. Justice becomes merely a useful convention for coordinating behavior under certain empirical conditions. But this cannot provide the kind of unconditional obligation that justice requires. In the Aristotelian tradition, justice is a virtue—a settled disposition to give each person their due—and it is essential to human flourishing, not merely useful for social cooperation. Hume's conventionalism about justice, like his emotivism about morality generally, represents the fragmentation of moral discourse that occurs when we lose the teleological framework of the virtue tradition.