Philosophy Practical Moral Skepticism
Anita M. Superson
  • LAST REVIEWED: 02 May 2023
  • LAST MODIFIED: 27 April 2017
  • DOI: 10.1093/obo/9780195396577-0343


The issue of why be moral is one of the most intractable in moral philosophy. Plato is the first Western philosopher to address it extensively in The Republic. In the dialogue, Thrasymachus asserts that justice is the interest of the stronger, which he illustrates with the story of the ring of Gyges. The ring, when turned a certain way, makes its bearer invisible and thus able to escape detection when acting immorally. Glaucon challenges Socrates to demonstrate that the just life is more advantageous than the unjust life, or, that rationality requires being a moral person. In the 1600s, Thomas Hobbes addresses the skeptic who wants to be shown that every morally required action is rationally required and who understands rational action to be identified with self-interested action, or, action that best satisfies one’s desires or preferences. Hobbes develops his contractarian moral theory in the context of his attempt to defeat a self-interest based skeptic about moral action. Henry Sidgwick, in the late 1800s, argues that there are two equally compelling sets of reasons—moral and prudential—and that there is no way to adjudicate between them such that one always overrides the other. Immanuel Kant argues that reason requires that one follow duty rather than inclination even when following morality thwarts all one’s inclinations, self-interested or otherwise. David Hume believes that most of us have reasons to be moral grounded in the universal sentiment of sympathy or benevolence, but for others, such as the sensible knave, who lacks such feelings, Hume offers self-interested reasons having to do with peace of mind, reputation, and the like, and, if these be rejected, there is nothing more to say. Aristotle’s approach was similar on this last point, as he addresses his discussion of this issue to those who are already at least somewhat disposed to morality or at least not pigheaded about the arguments for following it. Since the time when these historical figures tackled the issue of why be moral, it has been largely ignored. We might extract from error theory, the view that all moral talk is false because there are no moral facts, that the practical skeptic’s challenge is moot. Recently, however, the topic of practical skepticism has garnered significant attention since 1986 when David Gauthier, in the spirit of Hobbes, proposed a self-interest based contractarian theory with an eye to defeating the skeptic who wants it to be shown that every morally required action is rationally required. This theory of rational action and choice, known as the expected utility theory, is appealed to heavily by economists and social scientists and is taken by Gauthier to be the parameter within which skepticism needs to be defeated for the reason that self-interested action is seen as action that is most in opposition to moral action. Hence, if the skeptic is successfully defeated, the moral philosopher will have defeated the worst-case scenario against morality. Some philosophers after Gauthier adhere to the Hobbesian strategy and propose different answers to the skeptic, while others propose different moral theories and in their context address skepticism, and still others challenge the way the skeptic’s position is traditionally defined. Other challenges are more indirect, aiming at the expected utility theory, the notion of self-interest as desire satisfaction, and the legitimacy of the desires that rationality dictates the agent to satisfy. An issue related to skepticism is that of the possibility of rational amoralism. The amoralist recognizes that there is a reason to act morally but denies the force of moral reasons, believing that they do not necessarily motivate. Internalists about reasons and motives, who endorse a position known as motivational internalism, deny that amoralism is a tenable position, while externalists, who deny the necessary connection between reasons and motives, insist that it is. The vast amount of literature on this debate takes the issue of skepticism to a deeper level than merely demonstrating the overridingness of moral reasons. A similar point can be made about the issue of the authority of moral reasons, or whether moral reasons necessarily bind a rational person. Demonstrating that acting in morally required ways is rationally required addresses the theoretical skeptical challenge, while demonstrating that moral reasons necessarily take on, or grip, rational agents addresses the practical skeptical challenge.

Responses to Skepticism

back to top

Users without a subscription are not able to see the full content on this page. Please subscribe or login.

How to Subscribe

Oxford Bibliographies Online is available by subscription and perpetual access to institutions. For more information or to contact an Oxford Sales Representative click here.