Skip to main content

Because I Believe It’s the Right Thing to Do


Our beliefs about which actions we ought to perform clearly have an effect on what we do. But so-called “Humean” theories—holding that all motivation has its source in desire—insist on connecting such beliefs with an antecedent motive. Rationalists, on the other hand, allow normative beliefs a more independent role. I argue in favor of the rationalist view in two stages. First, I show that the Humean theory rules out some of the ways we ordinarily explain actions. This shifts the burden of proof onto Humeans to motivate their more restrictive, revisionary account. Second, I show that they are unlikely to discharge this burden because the key arguments in favor of the Humean theory fail. I focus on some of the most potent and most recent lines of argument, which appeal to either parsimony, the teleological nature of motivation, or the structure of practical reasoning.

This is a preview of subscription content, access via your institution.


  1. 1.

    Reported in the New York Times, Nov. 16, 2010, (Thanks to Bradford Cokelet and David Shoemaker for bringing this to my attention.)

  2. 2.

    I include the requisite caveat that this view might not have been Hume’s. I stick with “Humeanism” because it is rather entrenched. As we’ll see, the label “instrumentalism” is perhaps better; it can be mentally substituted by the reader if desired.

  3. 3.

    E.g. Williams (1979/1981), Velleman (1992), Lenman (1996), Zangwill (2003), Mele (2003), Finlay (2007), Sinhababu (2009).

  4. 4.

    E.g. Nagel (1970), McDowell (1978/1998), Darwall (1983), Korsgaard (1986/1996), Wallace (1990/2006), Smith (1994), Scanlon (1998), Shafer-Landau (2003).

  5. 5.

    For a more empirical approach, see my companion paper (May ms).

  6. 6.

    I follow the philosophical use of “desire” to be broad enough to refer to any essentially motivational or conative mental state. We can make do with the general idea of directions of fit, though we needn’t rely on a very specific characterization (e.g. as in Smith 1994, ch. 4.6). Roughly, beliefs aim to accurately represent; desires aim to bring about their contents (to be efficacious). But, as we’ll see, we should not broaden the notion of desire so much that it includes mere dispositions to transition between states.

  7. 7.

    Perhaps a better term for motivated desires would be “reason-based desires” (a term some writers use in a similar sense). I stick with Nagel’s terminology only because it is fairly common currency in this context.

  8. 8.

    See Mele (2003, pp. 33–4) for an elaboration of this distinction (though under the labels “intrinsic” vs. “extrinsic” desires). Some deny the existence of instrumental or extrinsic desires (e.g. Finlay 2007, §2). We needn’t adjudicate that debate here.

  9. 9.

    My characterization of these views is highly indebted to Jay Wallace’s, which is done in terms of his “desire-out, desire-in” principle (1990/2006, p. 30); cf. also Wedgwood (2002). But my explication of the positions is more concise and, I hope, clear.

  10. 10.

    I assume moral considerations provide at least prima facie reasons for action, and thus are normative. Moral discourse at least “aspires to normative significance,” as Wallace (2006) puts it.

  11. 11.

    A note on terminology: motivational rationalism is essentially what Jonathan Dancy (1993, ch. 1) calls “motivated desire theory” or the “hybrid theory,” not the “pure theory” which is committed to the existence of besires. Unlike Michael Smith (1994, p. 211, n. 12), I do not read Nagel as pursuing the besire strategy (see Nagel 1970, pp. 29, 32). For another reading of Nagel (as well as McDowell and Kant) along these lines, see Dancy (1993, ch.1)—p. 16n22 (attached to p. 9) is especially illuminating here. A related point of departure from Smith: what he calls “the Humean theory of motivation” is roughly the claim that intentionally performing some action A requires a preceding desire to A (and a relevant belief). I do not follow him in this terminology because those in the rationalist tradition, including Smith, need not (and tend not to) deny it (cf. Wallace 1990/2006).

  12. 12.

    I will even more quickly set aside “anti-psychologistic” theories which maintain that explaining rational action needn’t appeal to mental states at all. While I do not have the space to argue against that view here, the parties in our present dispute both accept psychologistic theories.

  13. 13.

    Smith likely intends externalism to capture what we have called “motivational Humeanism.” But the views are importantly distinct as currently defined. A key difference is that the Humean theory is partly a causal claim, whereas externalism is meant to be a conceptual claim involving a material conditional, which entails nothing about causation.

  14. 14.

    This problem is related to but distinct from Smith’s well-known “moral fetishism” argument against externalism. There a several powerful responses to that argument (for a recent discussion, see Julia Markovits 2010). But such responses don’t apply to the charge of revisionary explanations.

  15. 15.

    There is also empirical evidence that normative beliefs play a substantial role in much of our everyday motivational structures (see Holton 2009, ch. 5). But I leave development of that argument to another paper (May ms).

  16. 16.

    Reported in The Australian, April 1, 2011,

  17. 17.

    Google has about 17.7 million results for explanations employing explicitly cognitive terms, such as “because she thought it was the right thing to do” or “because I knew it was the right thing to do.” And we should add to that the 17.8 million results for “because it was the right thing to do,” which is natural for first-personal attributions of the belief. That yields a total of over 35 million results employing explicitly cognitive explanations. Yet conative explanations, using phrases such as “because he wanted to do the right thing,” yield a total of only 4.5 million results. And these can be read merely de re.

  18. 18.

    Something like this sort of argument might be found in Nagel (1970, esp. ch. 6).

  19. 19.

    Compare C. D. Broad (1950) in the context of discussing egoism: “Now I do not myself share that superstitious reverence for the beliefs of common sense which many contemporary philosophers profess. But I think that we must start from them, and that we ought to depart from them only when we find good reason to do so” (pp. 230–1).

  20. 20.

    In fact, some rationalists argue that the Humean theory is less parsimonious (e.g. Barry 2010, p. 209). But we needn’t rely on that strong of a claim.

  21. 21.

    Williams (1979/1981) also might be read as employing, very briefly, a similar kind of argument (see pp. 108–9), though for the most part he seems to just assume motivational Humeanism. Insofar as he does offer a teleological argument, I think it fails for the same reasons.

  22. 22.

    It’s a bit unclear whether this dispute is merely terminological. Finlay’s preferred terms are highly technical. In this context, we cannot simply appeal to our pre-theoretical linguistic intuitions to determine the extension of terms like “agency,” “teleology,” “volition,” “willing,” or “voluntary response to normativity.” But I set aside these issues here.

  23. 23.

    A similar Humean take on practical tortoises is developed by Peter Railton (1997, pp. 76ff). However, he appeals to such considerations to explicitly defend a Humean theory of practical reason, not motivation (though he does seem to assume the latter).

  24. 24.

    Blackburn of course is a non-cognitivist, but his argument in this paper seems to be independent of whether non-cognitivism is true.

  25. 25.

    In fact, we might locate this in Smith’s (1987, pp. 58–9) response to Nagel’s (1970/1978) argument.

  26. 26.

    Mele (2003, Ch. 4) seems to suggest a similar argument that falls prey to this objection. See May (ms).

  27. 27.

    For a similar take on tortoises-style considerations, in both the practical and theoretical domains, see James Dreier (1997, §5).

  28. 28.

    A version of this paper was presented at the 3rd Annual Workshop on Ethics and Mind at the University of Miami in November 2010. The paper has improved enormously from the constructive criticism of the participants, especially Bradford Cokelet and John Doris. For feedback on other occasions, I also thank Wesley Buckwalter, Stephen Finlay, Christopher McMahon, Ian Nance, Scott O'Leary, Jonathan Way, Aaron Zimmerman, and two anonymous reviewers for this journal.


  1. Barry M (2007) Realism, rational action, and the humean theory of motivation. Ethical Theory Moral Pract 10(3):231–42

    Article  Google Scholar 

  2. Barry M (2010). Humean theories of motivation. Oxford Studies in Metaethics, vol 5. Shafer-Landau R (ed) Oxford University Press, pp 195–223

  3. Blackburn S (1995/2010) Practical tortoise raising. Reprinted in Blackburn, Practical Tortoise Raising: and Other Philosophical Essays (Oxford University Press, 2010), pp 7–25. Originally published in Mind 104(416):695–711

  4. Broad CD (1950) Egoism as a theory of human motives. Reprinted in his Ethics and the History of Philosophy: Selected Essays, London: Routledge and Kegan Paul, 1952, pp 218–31 (Originally published in 1950: The Hibbert Journal 48:105–114)

  5. Burge T (1979/2007) Individualism and the mental. In Foundations of Mind, Oxford University Press, pp 100–150. (Originally published in Midwest Studies in Philosophy 4 (1979), pp 73–121)

  6. Carroll L (1895) What the tortoise said to achilles. Mind 4(14):278–80

    Article  Google Scholar 

  7. Dancy J (1993) Moral reasons. Wiley-Blackwell

  8. Darwall S (1983) Impartial reason. Cornell University Press

  9. Davidson D (1963/1980) Actions, reasons, and causes. Essay 1 in his essays on actions and events. Oxford University Press, pp 3–19. (Originally published in 1963, Journal of Philosophy, 60(23):685–700)

  10. Dreier J (1997) Humean doubts about the practical justification of morality. In: Cullity G, Gaut B (eds) Ethics and practical reason. Clarendon, Oxford, pp 81–100

    Google Scholar 

  11. Finlay S (2007) Responding to normativity. In: Shafer-Landau R (ed) Oxford studies in metaethics, 2nd edn. Oxford University Press, Oxford, pp 220–39

    Google Scholar 

  12. Haidt J & Bjorklund F (2008) Social intuitionists answer six questions about morality. In: Sinnott-Armstrong W (ed) Moral psychology, vol 2. MIT Press, pp 181–218

  13. Holton R (2009) Willing, wanting, waiting. Clarendon, Oxford

    Book  Google Scholar 

  14. Hume D (1739–40/2000) A treatise of human nature. Norton DF, Norton MJ (eds). Oxford University Press

  15. Hume D (1751/1998) An enquiry concerning the principles of morals. Beauchamp TL (ed) Oxford University Press

  16. Korsgaard C (1986/1996) Skepticism about practical reason. Reprinted in Korsgaard, Creating the Kingdom of Ends, Cambridge University Press (1996), pp 311–34 (Originally published in 1986, The Journal of Philosophy 83(1):5–25)

  17. Lenman J (1996) Belief, desire and motivation: an essay in quasi-hydraulics. Am Philos Q 33(3):291–301

    Google Scholar 

  18. Markovits J (2010) Acting for the right reasons. Philos Rev 119(2):201–242

    Article  Google Scholar 

  19. May, Joshua. Toward a naturalistic Motivational Rationalism. Monash University. Acessed January 20, 2011

  20. McDowell J (1978/1998) Are moral requirements hypothetical imperatives? Reprinted in McDowell, Mind, Value, and Reality (Harvard University Press, 1998), pp 77–94 (Originally published: Proceedings of the Aristotelian Society, Supplementary 52:13–29+31–42)

  21. Mele A (2003) Motivation and agency. Oxford University Press, New York

    Book  Google Scholar 

  22. Nagel T (1970) The possibility of Altruism. Oxford University Press, Oxford

    Google Scholar 

  23. Quinn W (1993/1995) Putting rationality in its place. Reprinted in Virtues and Reasons: Philippa Foot on Moral Theory. Hursthouse R, Lawrence G, Quinn W (eds) Oxford: Clarendon Press. (Originally published in 1993: R. Frey and C. Morris (eds.), Value, welfare and morality. Cambridge University Press)

  24. Railton P (1997) On the hypothetical and non-hypothetical in reasoning about belief and action. In: Cullity G, Gaut B (eds) Ethics and practical reason. Clarendon, Oxford, pp 53–79

    Google Scholar 

  25. Scanlon TM (1998) What we owe to each other. Harvard University Press, Cambridge

    Google Scholar 

  26. Shafer-Landau R (2003) Moral realism: A defence. Clarendon, Oxford

    Book  Google Scholar 

  27. Sinhababu N (2009) The humean theory of motivation reformulated and defended. Philos Rev 118(4):465–500

    Article  Google Scholar 

  28. Smith M (1987) The humean theory of motivation. Mind 96(381):36–61

    Article  Google Scholar 

  29. Smith M (1994) The moral problem. Blackwell (First published in the U.S. in 1995)

  30. Smith M (1996) The argument for internalism: Reply to miller. Analysis 56(3):175–184

    Article  Google Scholar 

  31. Velleman JD (1992) What happens when someone acts? Mind 101(403):461–481

    Article  Google Scholar 

  32. Wallace RJ (1990/2006) How to argue about practical reason. Reprinted in Wallace, Normativity and the Will, Oxford University Press (2006), pp 15–42 (Originally published: 1990 in Mind 99 (395):355–385)

  33. Wallace RJ (2006) Moral reasons and moral fetishes: Rationalists and anti-rationalists on moral motivation. Ch. 14 in Wallace, Normativity and the Will, Oxford University Press, pp 322–342

  34. Wedgwood R (2002) Practical reason and desire. Australas J Philos 80(3):345–358

    Article  Google Scholar 

  35. Williams B (1979/1981) Internal and external reasons. Reprinted in Williams, Moral Luck, Cambridge University Press (1981), pp 101–113 (Originally published in Rational Action, Ross Harrison (ed), Cambridge University Press, 1979)

  36. Zangwill N (2003) Externalist moral motivation. Am Philos Q 40(2):143–154

    Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Joshua May.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

May, J. Because I Believe It’s the Right Thing to Do. Ethic Theory Moral Prac 16, 791–808 (2013).

Download citation


  • Humeanism
  • Humean theory of motivation
  • Rationalism
  • Evaluative beliefs
  • Internalism
  • Externalism