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Why Be Good?

On What Matters

by Derek Parfit
Oxford University Press, Volume 1: 540 pp., $35.00; Volume 2: 825 pp., $35.00


Philosophers have long sought to formulate a theory that explains the purposes of commonsense moral rules and provides principles enabling us to resolve the frequent moral dilemmas we encounter. Thomas Hobbes wrote that familiar moral rules are not relative to one culture or another but are “articles of peace,” necessary to civilized social life. It is in everyone’s rational self-interest to obey these rules; the grim alternative is a “state of war.” Immanuel Kant said that we have an unconditional duty to obey morality regardless of our desires and self- interests. His second “categorical imperative” says that we ought never treat others “merely as means,” but always as “ends in themselves.” To do so, we should follow a general principle that we believe everyone should follow in circumstances like our own.

Steve Pyke/Getty Images
Derek Parfit, 1991

Kant held that his imperative justifies our commonsense duties to each other and provides a more fine-grained method of reasoning about what we ought to do when ordinary moral rules do not adequately address the complexities of life. For example, under what circumstances is it permissible to break a promise or deceive someone? To save innocent life or prevent great harm, surely, but not to benefit ourselves in minor ways; the hard cases lie in between.

In The Methods of Ethics (1874), among the greatest works in moral philosophy since Kant, the British philosopher Henry Sidgwick countered that the rules of commonsense morality coincide with utilitarianism. The “principle of utility” says that our actions are right and our laws are just to the degree that they promote the greatest sum of “utility,” or happiness, in the world. Happiness, Sidgwick says, is basically pleasurable experiences.

Contemporary utilitarians often identify happiness (now called “welfare” or “well-being”) with satisfaction of preferences, or of rationally informed desires. Until John Rawls’s influential social contract theory, expounded in A Theory of Justice (1971), utilitarianism remained the predominant moral theory in Anglo-American philosophy for over two hundred years. Utilitarianism remains highly influential among economists, in business and law schools, and in public policy institutes. In each it is common to hear arguments that a law or practice is justified because it improves overall well-being.

Utilitarianism is the most prominent example of a family of positions called “consequentialism.” These positions hold that actions, laws, or other conventions are right to the degree that they produce the best consequences, effectively “maximizing” the good. Many consequentialists today consider utilitarian general happiness only one of the good consequences that right conduct ought to promote. Some say that equalizing the distribution of happiness is also important. Some consequentialists endorse, as among the “intrinsic goods” that ought to be promoted, goods such as knowledge, creativity, aesthetic appreciation, love and friendship, or individual freedom.

Joining consequentialism and Kantianism is a third major position in contemporary moral philosophy, Harvard philosopher T.M. Scanlon’s “contractualism,” which reflects Rawls’s social contract theory of justice, the main influence on Scanlon. Rawls contends that justice requires that we act upon principles that would be unanimously agreed to among free persons equally situated behind an impartial “veil of ignorance” where they do not know particular facts that would bias their judgments.

Modifying Rawls’s social contract to apply it to personal duties, Scanlon’s contractualism says that we owe to each other a general duty to act on moral rules—such as not harming others and honoring our promises—that it would be unreasonable for anyone to reject. Contractualism resembles Kantian views in that it sees the morality of right and wrong as duties we owe to one another in recognition of our equal status as persons. In this respect, both stand together in opposition to consequentialist views, which construe right and wrong as derived from an impartial duty to promote the best overall states of affairs in the world, even if in the course of doing so what contractualists see as moral duties to persons may not be fulfilled.


Consequentialism, Kantianism, and contractualism are currently the three predominant positions in moral philosophy, and they are the primary subject of On What Matters, Derek Parfit’s enormous two-volume treatise.1 The book is divided into three main discussions: Part I, “Reasons,” argues for the objectivity of reasons for acting; Parts II–V are on the three main moral theories just mentioned; and Part VI, “Normativity,” defends the truth of moral and other normative judgments. There is also a helpful introduction by the book’s editor, Samuel Scheffler, and four critical commentaries by the philosophers Susan Wolf, Barbara Herman, Allen Wood, and Scanlon.

Parfit’s treatise is driven by two overarching concerns. First, he hopes to show that moral philosophy’s three predominant positions converge into a “Triple Theory.” Parfit’s Triple Theory says, first, that right and wrong are determined by moral rules that, when generally accepted, “optimize,” or promote the best overall consequences in the world. Though this sounds like a form of consequentialism—indeed Parfit calls it “Kantian rule consequentialism”—he offers both contractualist and Kantian arguments for it, appealing to the idea that the rules are ones that it would be unreasonable for anyone to reject, and that we all have reason to consent to them. Hence the designation “Triple Theory.”

Parfit’s second main concern is the truth and objectivity of morality and of reasons and values more generally. He argues that the statements we make about moral duties and valuable activities are not subjective or culturally relative, but are objectively true or false. Things are valuable, independent of whether we desire or value them. It is for Parfit an objective truth that happiness is good, suffering is bad, and that “no one could ever deserve to suffer.” If the reasons for moral and evaluative choices are objective and they justify true statements about duties and values, then moral and value relativism, subjectivism, and nihilism must be false. This is the main conclusion of Parts I and VI.

Parfit uses these two concerns to address the question of “what matters.” He discusses some of the things that ultimately matter—primarily happiness and an absence of human and nonhuman suffering. But he is especially concerned with showing that something must matter, independent of our subjective and culturally relative beliefs and desires. If there are no objective reasons or values but only desires and beliefs about what matters, then there are no truths about morality and what we ought to do. But then, Parfit contends, nothing can truly matter—regardless of how much we care about it—and we are condemned to nihilism. On What Matters dryly sets forth countless arguments, but its author is passionate in his conviction that there must be objective values that give meaning to our lives in a godless world. It is rare to find an academic philosophical treatise that sincerely grapples with such cosmic questions as “whether human history has been worth it,” given all the suffering that has existed in the world.


In Part I of On What Matters, “Reasons,” Parfit—challenging a fundamental premise of our consumer culture—denies that we have any reason at all to satisfy our own desires or preferences for their own sake. He argues the radical position that the mere fact that an action would promote the satisfaction of some desire is never in itself a reason for the person to do that action. People can and do desire most anything. For example, it’s conceivable, Parfit says, that a person could desire to be in agonizing pain. Surely this desire gives him no reason to satisfy it by putting his hand in the fire. In order for a person to have a reason to act as he desires, there must be some feature of the object of desire that makes it worth desiring. Practicing the piano in order to play better may be a goal worth desiring. Producing agonizing pain by burning your hand is not such a goal.

The position Parfit attacks here is known as “the desire-based theory of reasons.” It has enormous influence in philosophy, economics, political science, rational choice theory, and other academic disciplines. Underlying the desire-based theory is the premise that, in order for us to have a reason for doing anything, we must be motivated to act; and this requires a desire that propels our behavior. For our capacities for reasoning and intellect are, as David Hume said, “inert,” incapable of moving people to act in the absence of some desire, whether for wealth or knowledge or power or others’ happiness, for example.

The account of rationality implicit in economics and rational choice theory presupposes the desire-based theory of reasons for acting. In both, by definition it is rational for a person to maximize his individual utility: that is, to act to satisfy consistently ordered preferences for what he most wants. Parfit argues in effect that we have no reason to maximize our utility if we do so regardless of the objects of our desires. Whether we have reason to do what we most want depends, instead, upon the value of the objects of our desires, and the reasons these objects give us for acting. Pleasure, knowledge, love and friendship, aesthetic appreciation, justice and equality, and many other ends might be good reasons for acting and hence worthy of desire. But it’s these objective values themselves, and not the mere fact that we desire them, that provide us with reasons to pursue them.2

Economists may say they are insulated from these criticisms, since their task is to explain, not justify, individual and group behavior. We often talk about “the reasons” a person had for acting (e.g., Caesar’s reasons for crossing the Rubicon), referring to the beliefs and desires that cause conduct, with no moral or evaluative connotations. Parfit and other critics recognize this causal usage. What they object to is the subtle transition from a causal to a normative use of “reason for acting,” which implies what people ought to do. Economists and rational choice theorists, wittingly or not, make this transition when they say that a person acts “irrationally” by not maximizing his individual utility.

Parfit’s position implies that we often do not have sufficient reasons to act rationally by maximizing our own utility; and that acting nonrationally (if not irrationally) by refusing to satisfy certain utility-maximizing preferences (e.g., to steal, or cheat on taxes, knowing we will not be discovered) can be the best course of action. If Parfit is right, then ambitious economists perhaps should abandon their claim that economics is a “science of rational choice” and instead entitle it the “science of consistent, self-interested choice.”


It is difficult to understand Kant’s second categorical imperative, that we are never to treat others “merely as means” but always as “ends in themselves,” when that imperative is isolated from the rest of Kant’s moral philosophy. Parfit nonetheless tries. He simplifies his task by focusing exclusively on treating others “merely as means,” disregarding the idea of treating persons as ends. Clearly Kant cannot mean we should never rely on others as means to achieve our purposes; for it would be hard to make it through life without the services of strangers (grocers, physicians, teachers, garbage collectors, etc.). But instrumentally relying upon others is different from treating them merely as means, with no regard for their rights and interests—as if they were slaves. To rob someone at gunpoint, or transplant her kidneys without her consent, is to treat her merely as a means. Parfit suggests, however, that even when we harm others, we do not treat them merely as means if we deprive them of no more than is necessary to prevent a greater harm to someone else. Suppose you sacrifice a person’s leg to save another’s life, while refraining from sacrificing his second leg to save your computer. Since the victim’s well-being is considered and is sacrificed only for a greater good, it cannot be said that the victim is treated “merely as a means.”

  1. 1

    There has been a revival of Aristotelian “virtue ethics” in recent years, though it is ignored by Parfit. 

  2. 2

    Other philosophers also argue that reasons are objective and are not based in desire, notably Thomas Nagel, Joseph Raz, and Scanlon. 

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