Hume’s better argument for motivational skepticism

Abstract

On a standard interpretation, Hume argued that reason is not practical, because its operations are limited to “demonstration” and “probability.” But recent critics claim that by limiting reason’s operations to only these two, his argument begs the question. Despite this, a better argument for motivational skepticism can be found in Hume’s text, one that emphasizes reason’s inability to generate motive force against contrary desires or passions. Nothing can oppose an impulse but a contrary impulse, Hume believed, and reason cannot generate an impulse. This better argument is here developed and defended. Two lines of objection to it can be anticipated: (1) that reason actually can generate impulsive force, based on contents of its normative judgments and (2) that reason neither can nor needs to generate an impulse, since the actions of rational agents are not determined by forceful impulses of desire, as Hume supposed. These objections are answered by pointing out their unsatisfying consequences.

Keywords:

• practical reason
• motivation
• internalism
• Hume
• Kant

Acknowledgements

We thank two anonymous reviewers for their comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Elizabeth S. Radcliffe is Professor of Philosophy at The College of William & Mary. Her areas of special interest include early modern philosophy (especially Hume and his contemporaries), moral philosophy, action theory, and motivational psychology. She is author of Hume, Passion, and Action (Oxford University Press, 2018) and editor of A Companion to Hume (Blackwell, 2008).

Richard McCarty is Professor of Philosophy at East Carolina University. His research focuses on Kant’s practical philosophy, and on related figures in the history of modern philosophy. He is co-editor, with Elizabeth Radcliffe, of Late Modern Philosophy: Essential Readings with Commentary (Blackwell, 2007) and author of Kant’s Theory of Action (Oxford University Press, 2009).

Notes

1 Some recent commentators have lately challenged this traditional view of Hume’s psychology, having become convinced that his view of belief allows that beliefs can motivate independently of antecedent desires. See, for example: Sturgeon (2015, 251–282); Pigden (2009, 97); Kail (2007, 197–198); Cohon (2008, 73–77); Owen (2016, 333–355); and Karlsson (2006, 235–255). We are not persuaded by these new readings, but to explain why would take this paper in a different direction. For arguments against these philosophers’ interpretations, see Radcliffe (1999, 2012).

2 References to Hume’s Treatise are by book, part, section, and paragraph number.

3 Parfit (1997, 128–129); but for a contrary reading of Hume see Phillips (2005).

4 None of the following philosophers or theologians concerned with this topic argued that reason by itself motivates to action: Descartes (1649), Malebranche ([(1674–1675) 1980]), Cudworth [1731] 1838, and Clarke (1724); lesser-known French philosophers Jean-François Senault (1641), Nicolas Coeffeteau (1621), and Marin Cureau de La Chambre (1658); and minor English theorists William Ayloffe (1700), Francis Bragge (Vicar of Hitchin) (1708), Walter Charleton (M. D.) (1674), and Edward Reynolds (1640). Spinoza [1677] 2000 thought reason alone could motivate, but he characterized it as an affective state.

5 When Hume is criticized for denying reason’s practicality, more than one line of defense against this criticism is possible. It can be argued: (i) that his skeptical argument is actually better than his critics charge or (ii) that since there is a plausible sense of reason’s being “practical” that he endorsed, or could have endorsed, he actually was not the skeptic of practical reason he is alleged to be. Our argument takes the first line of defense, while most of the recent literature on Hume and practical reason takes the second line. See, for example: Blackburn (2000); Mason (2005); Phillips (2005); Shafer (2008); and Kong (2013). We are here concerned about the validity of Hume’s argument at T 3.1.1.6, which is critical of rationalist ethical theories. If his earlier argument for motivational skepticism (T 2.3.3.3) cannot withstand criticism, then neither can his subsequent criticism of moral rationalism. As interesting and instructive as the project of developing a “Humean” theory of practical rationality may be, we do not see this project as supporting Hume’s powerful criticism of moral rationalism.

6 Korsgaard writes, for example, that, “An internalist theory is a theory according to which the knowledge (or the truth or the acceptance) of a moral judgment implies the existence of a motive (not necessarily overriding) for acting on the judgment” (1996a, 315, emphasis altered).

7 The label comes from Sellars (1974, 34).

8 Capitalism is sometimes justified as a form of beneficence. For example, “Benefitting oneself by providing what others need is the raison d'etre of the whole affair” (Acton 1971, 16).

9 It might be tempting to say that since ordinarily she can raise her arm when she desires to do so, the change of physical circumstances in the example proves that the fault must lie in her arm, and not in her desire. But this begs the question, by assuming that strength of desire is different from strength of the body. When desire-strength is explained as proposed here, then it is impossible to tell whether success in raising one’s arm would be attributable to desire-strength or to body-strength, even under ordinary physical conditions. For in ordinary conditions, just as in the launch-pad example, the impediment to raising one’s arm may be nothing other than gravity; and if the arm should fail to rise, there is no way to tell whether the weakness lies in the desire, or in the arm.