An Enquiry Concerning the Principles of Morals

Context and Aims

An Enquiry Concerning the Principles of Morals (1751) is David Hume’s mature statement of his moral philosophy, a revision and condensation of Book III of his earlier A Treatise of Human Nature (1739–40). Dissatisfied with the Treatise’s reception and stylistic density, Hume re‑presented his ethical views in a clearer and more accessible form. He later described the Enquiry as “incomparably the best” of his writings.

The work belongs to the tradition of British moral sense theory, which emphasizes sentiment and feeling in moral judgment. Hume’s main aim is to identify the “principles of morals”—the psychological and social bases of our ideas of virtue and vice—and to argue that these are fundamentally rooted in human sentiment, not in pure reason or divine command.

Central Doctrines

At the heart of the Enquiry is Hume’s sentimentalist thesis: moral distinctions are “more properly felt than judg’d of.” Hume argues that:

• Reason alone can discover relations of ideas or matters of fact, but it cannot by itself generate moral approval or disapproval.
• Moral judgment essentially involves a feeling of pleasure (in response to virtue) or uneasiness (in response to vice).
• These feelings are neither purely idiosyncratic nor arbitrary; they are shaped by shared human nature and by the operation of sympathy.

Hume defines virtue as any quality of mind that is either immediately agreeable or useful to the person who possesses it or to others. Conversely, vice is what is immediately disagreeable or harmful. This yields a fourfold classification:

1. Qualities useful to others (e.g., justice, fidelity, industry)
2. Qualities immediately agreeable to others (e.g., good manners, wit, modesty)
3. Qualities useful to oneself (e.g., prudence, temperance, perseverance)
4. Qualities immediately agreeable to oneself (e.g., cheerfulness, a sense of humor, pride when properly regulated)

Across these categories, Hume emphasizes utility and agreeableness as the bases of moral approval, giving his theory a broadly utilitarian character, though couched in psychological rather than purely normative terms.

A central explanatory mechanism is sympathy. By sympathy Hume means a natural propensity to receive the feelings of others and to be affected by their happiness or misery. Sympathy allows us to:

• Extend our concern beyond narrow self-interest
• Feel pleasure at the happiness that virtues promote
• Adopts a more general and impartial viewpoint, correcting for our immediate biases and partialities

This “correction” explains how we come to approve traits that may not directly benefit us personally but promote the “interest of society” more broadly.

Structure and Major Themes

The Enquiry is composed of a brief Preface and twelve sections, moving from methodological questions to detailed discussions of particular virtues.

1. Method and Preliminary Distinctions: Hume argues that moral philosophy should be grounded in empirical observation of human nature, modeling itself on the “experimental method” used in natural science. He distinguishes between “natural” and “artificial” virtues and between moral and other forms of evaluation (such as aesthetic judgment).

2. Reason and Sentiment: Hume criticizes rationalist accounts (associated with Samuel Clarke and others) that ground morality in eternal relations discerned by reason. He maintains that reason can inform us of facts and relations relevant to action but cannot directly move the will or generate moral praise and blame. This supports his claim that sentiment is “the source of moral distinctions.”

3. Natural and Artificial Virtues: Hume distinguishes natural virtues, which arise directly from human nature (e.g., benevolence, generosity), from artificial virtues, which depend on social conventions and institutions (e.g., justice, fidelity to promises). This distinction allows him to give a genealogical account of certain social practices.

4. Justice as an Artificial Virtue: One of the most influential sections is Hume’s account of justice and property. He argues that rules of justice emerge under conditions of moderate scarcity and limited generosity, where unregulated self-interest would generate conflict. Through convention, individuals converge on stable rules regarding property and promise-keeping because these rules are mutually advantageous. Justice thus has no foundation in an abstract natural right, but in its utility for social order and cooperation.

5. Benevolence and the Common Good: Hume insists that benevolence is a central and genuine motive in human life, countering the psychological egoism of writers such as Hobbes and Mandeville. He holds that we naturally take pleasure in the happiness of others, especially when filtered through sympathy. This explains our approval of traits that advance the common good, and supports Hume’s alignment of virtue with what promotes public utility.

6. The General Point of View: Hume confronts the problem of subjective bias: people are more affected by what is close to them in time, space, or personal relation. He argues that, in moral thinking, we habitually adopt a “general point of view”, correcting for these biases. From this standpoint, we evaluate characters and actions “as they appear to a judicious spectator,” not simply in terms of private advantage. This device preserves the apparently objective and public character of moral discourse while maintaining a sentimentalist foundation.

7. Religious and Metaphysical Considerations: Hume downplays theological foundations for morality, emphasizing that our moral sentiments are intelligible without appeal to divine command. Morality, he suggests, depends on human nature, not on speculative metaphysics. This secular orientation was controversial in his time and remained a focal point for later criticism and admiration.

Reception and Influence

Upon publication, An Enquiry Concerning the Principles of Morals did not achieve the wide acclaim Hume hoped for, though it was generally better received than the Treatise. Over the 18th and 19th centuries, it became a central text in discussions of moral sense theory, sentimentalism, and utilitarianism.

The Enquiry influenced Adam Smith, whose Theory of Moral Sentiments develops related ideas about sympathy and the impartial spectator, as well as later British moralists, including Francis Hutcheson and early utilitarians. Hume’s emphasis on utility, sympathy, and the artificiality of justice shaped the intellectual background of Jeremy Bentham and John Stuart Mill, even where they departed from his strictly psychological framework.

Critics from rationalist and Kantian traditions have argued that Hume’s sentimentalism cannot adequately account for the apparent normative authority and universality of moral obligations, especially duties of justice that seem to bind regardless of inclination. Others contend that his reliance on sympathy risks reducing morality to contingent human psychology, leaving it vulnerable to cultural variation and bias.

Defenders and interpreters have responded by emphasizing the sophistication of Hume’s general point of view, his nuanced distinction between natural and artificial virtues, and his proto‑utilitarian insight that what we call “virtue” reliably tracks what promotes human flourishing and social stability.

In contemporary moral philosophy, the Enquiry is widely regarded as one of the classic formulations of moral sentimentalism and as a foundational work in the history of utilitarian and consequentialist thought. It continues to be studied both for its substantive ethical claims and for its methodological proposal that moral philosophy should be conducted as a science of human nature, grounded in careful observation of our sentiments, practices, and social life.