An Enquiry Concerning the Principles of Morals

An Enquiry Concerning the Principles of Morals (1751) is a philosophical classic by Scottish Enlightenment philosopher David Hume. In this book, Hume provides an empirical, organized, and systematic analysis of moral theory and judgment. For the sake of clarity, this summary will briefly tackle each of the main chapters and Appendices.

Hume begins by describing the most irksome kinds of arguers: the ones who are obstinate in their rightness and superiority and who will not unbend to hear anything contrary, and the Devil’s Advocates who do not believe in the argument, they just like to cause strife and controversy. Hume’s advice is, in modern parlance, don’t feed the trolls. Arguing with them is ineffective; it is best to ignore them and, starved for attention, they might begin to see common sense. Hume goes on to argue that although we would like to believe that morality is derived from reason, in truth, morality is connected to sentiment. In this way, Hume dismisses moral ideals. Instead, he examines how morality is formed through observation and psychology.

Benevolence and other human virtues of kindness temper and make palatable other qualities, such as ambition, success, and courage. Although the public might hate someone who embodies the latter qualities, benevolence will silence even the harshest of critics and build goodwill. For Hume, benevolence has great utility: it wins praise and commendation and gives the person who wields it a measure of influence over those who benefit. In other words, benevolence is a moral virtue because it has social utility and appeals to sympathy.



To Hume, justice is socially approved entirely for its relative utility, and depends “on the particular state and condition in which men are placed.” He provides several examples. In a utopian society where everyone has what he or she needs and is free of envy and possessiveness, justice would not be necessary. In a dystopia, where everyone is fighting just to get the basics to survive, justice is unfeasible. Justice is impossible in war because the parties involved no longer believe that justice has any use to them, and should a man fall into the clutches of a band of miscreants, he would have to abandon justice to survive. Yet, justice is foundational to society and morality. An expectation of justice and consequences keeps people from behaving lawlessly anytime they please. It is worth noting that Hume discusses justice mostly in relation to personal property, and only lightly in terms of acceptable conduct towards other humans and creatures.

Building on the idea that justice is foundational to society, Hume goes on to prove that morality in society is required because individuals need each other to survive. Justice and laws are instrumental in curbing our baser impulses. Princes must respect the sovereignty of other princes in order to negotiate and enforce treaties; parents must provide for their helpless young (somehow he connects this to requiring fidelity and chastity in women); laws of manners prevent altercations springing from discourtesy or gossip; games require rules to play; even murder is regulated. To function, society needs useful standards of right and wrong.

Hume argues, “Usefulness is agreeable, and engages our approbation.” Simply put, we pursue things that give us pleasure and joy, and things that bring pleasure are useful. We laud and appreciate virtue even in our enemies, and we are applauded when we display virtue as well. Recognition, influence, and approval make us happy. Being treated humanely by someone who has power over us also makes us happy. Social sympathy (empathy) allows us to share in the joys of others, and to be genuinely distressed on behalf of those who encounter misfortune. Social sympathy goes together with morality because those who display it often have a strong sense of right and wrong.



Hume contends, “No quality…is absolutely either blamable or praiseworthy. It is all according to its degree.” Fortune must be tempered by frugality—but not so much frugality that a man loses all joy in life and refuses hospitality to others. He writes that while all men want happiness, few get it, mainly because most lack the strength of mind and character to keep moving forward and taking risks. Weaker men get distracted and fall into vice. At least they get to redeem themselves; women who are not perfectly chaste are permanently ruined and can never prove their worth again. Beauty is a useful quality, as is strength. However, impotence in men and barrenness in women invites contempt.

He opens the chapter “Of Qualities Immediately Agreeable to Ourselves” with an observation that a moderately lively and cheerful person can perk up a gloomy crowd with infectious good humor. Enjoyment and cheerfulness are meritorious, and we think kindly about such people and their wit. Courage is also excellent, as is serenity. However, extremes of these qualities are demerits. For example, being too courageous can lead to foolhardiness. Overall, Hume maintains his argument that everything should be taken in moderation, even virtues.

In society, justice is necessary, but the virtues of common sense, cleanliness, humor, politeness, and modesty are all equally attractive qualities. However, arrogance, lying, vanity, and impudence invite scorn. Yet, desiring fame or reputation is a good thing, Hume argues. People have an inherent desire to please and gain others’ admiration and are more likely to do praiseworthy deeds in order to get those results.



In sum, morality is subjective and driven almost entirely by sentiment, including social sympathy and a desire for approbation. Certain qualities are useful because performing them bring desirable results, such as inclusions and protections of society, happiness, reputation, and good regard. Useful, agreeable, and companionable qualities are more attractive than negative or contrary qualities. Hume also believes that they are necessary for happiness—if we know and care that we have acted well, we have peace of mind and satisfaction with our own conduct. Those who behave contrary to morality, who behave unjustly, or who are indifferent to good and evil, will not.

This book was mostly a revision of the third book of A Treatise of Human Nature. Although Hume is repetitive, the book is clearly written and accessible to a general audience. He includes four appendices where he elaborates further on a few ideas: Concerning Moral Sentiment, Of Self-Love, Some Farther Considerations with Regard to Justice, and Of Some Verbal Disputes.