Moral

A characteristic component of eighteenth-century sentimentalist ethics was the rejection of the rationalist accounts of moral knowledge and motivation that supported theoretical views like those just summarized. Sentimentalist thinkers held that our awareness of moral good and evil, our ability to judge actions and character traits, and our motives for action depend on our capacity to be affected by feelings that are common to all human beings. The notion of a moral sense thus often figured prominently in the sentimentalists' portrayals of the source of our feelings of moral approval and disapproval. Contrary to the theorists of natural law discussed above, these theorists of moral sensibility tended not to regard concepts of law, obligation, and duty as primary ethical notions. Anthony Ashley Cooper, better known as the earl of Shaftesbury (1671–1713), understood virtue in terms of actions that give rise to feelings of approbation, actions that in turn show evidence of an agent's self-ordered affective harmony with respect to the feelings that move him to act. According to Francis Hutcheson (1694–1746), human moral sensibility is naturally structured in such a way that we approve of actions and character traits to the extent that they exhibit benevolent inclination as their motivating condition. Hutcheson formulated a theory of virtue in which universally benevolent inclination features as the morally best of motives. While David Hume (1711–1776) did not follow Hutcheson in maintaining that benevolent inclination supplied the only genuinely moral basis for action, he advanced a secular science of morality founded on the analysis of the moral sentiments and the human capacity for sympathy. Making use of the systematic superstructure of modern natural-law accounts of duties and rights, Hume constructed a comprehensive theory of the virtues revolving around the distinction between the "natural" virtues (such as compassion and generosity) and convention-dependent "artificial" virtues (such as justice). Jean-Jacques Rousseau (1712–1778) and Adam Smith (1723–1790) published highly influential treatises that further articulated the view that human morality has its grounds in the sensuous dimension of our nature.

A further type of approach was furnished by ethical theories that assumed egoistic explanations of moral motivation, typically in conjunction with hedonistic accounts of the good and proto-utilitarian principles requiring the maximal promotion of human happiness. These theories were often rooted in the Augustinian view of the sinfulness and corruption of human nature that was presupposed not only by Lutheran and Calvinist moral theology but also by French Jansenist ethical thought. Interweaving the Augustinian view with themes drawn from Hobbes's anthropology, Pierre Nicole (1625–1695) maintained that, although virtuous action is at bottom the result of self-interested passion, such selfish action has beneficial consequences for society as a whole. Bernard de Mandeville (1670–1733), writing in English, radicalized this line of thinking to the point of rupture with traditional religious conceptions of vice and sinfulness. While Mandeville's theory of morals scandalized his immediate contemporaries, the connection between selfish motivation and general utility came to be regarded with increasing favor during the eighteenth century. That connection provides a crucial element of the moral philosophies of Claude-Adrien Helvétius (1715–1771) and Paul-Henri-Dietrich d'Holbach (1723–1789), both of whom were important influences on the full-fledged utilitarian ethics of Jeremy Bentham (1748–1832). Bentham argued that the general happiness, to be promoted through actions and governmental policies, must be understood quantitatively in terms of the favorable balance of pleasure over pain, as experienced by separate individuals in the pursuit of their particular ends.

Immanuel Kant (1724–1804) sought the grounds of morality in concepts and principles of practical reason that could be established independently of facts about the sensuous dimension of human nature. Kant's major works on moral philosophy aimed to give an account of the fundamental moral law as a supreme formal principle of duty, which he called the categorical imperative. Kant thought of the categorical imperative as an objectively valid principle by which an agent can determine the moral content of subjective practical principles called maxims. Maxims conforming to the universality requirements expressed by the categorical imperative supply laws of practical reason that specify particular duties. The categorical imperative, however, is much more than just an abstract and legalistic formal principle of duty. For it requires the individual agent to make it her maxim to act in such a way that the maxims of her actions can be willed as universal laws, thus making the principle of duty itself the sufficient incentive for action, independently of inclination and sentiment. The rationally legislating human agent gives laws of duty to herself in conformity with the idea that every human will can be a will that legislates universally through all its maxims. Such is the Kantian idea of rational self-legislation as autonomy of the will. In keeping with this idea, Kant asserted that morality is "the relation of actions to the autonomy of the will, that is, to a possible giving of universal law through its maxims."