Motivation to the Means

Rationalists including Nagel and Korsgaard argue that motivation to the means to our desired ends cannot be explained by appeal to the desire for the end. They claim that a satisfactory explanation of this motivational connection must appeal to a faculty of practical reason motivated in response to desireindependent norms of reason. This paper builds on ideas in the work of Hume and Donald Davidson to demonstrate how the desire for the end is sufficient for explaining motivation to the means. Desiring is analyzed as having motivation towards making the end so, which is analyzed as engaging in mental activity aimed at facilitating that end. I conclude that it is constitutive of an agent’s desiring an end that he is motivated towards what he believes to be means. I desire a soda, so I feed a vending machine. What could be more mundane? But some perceive a difficult problem in explaining this motivation to the means: a problem for the orthodox Humean Motivation-by-Desire Principle, which holds that all motivation of action – causal influence towards activity exerted by minds1 – requires and is produced by conative psychological states like desire and aversion. How does a desire for one thing motivate action of doing something else? If this motivational transfer cannot be explained satisfactorily there is license for attributing the motivation to sources other than desire, such as rational acceptance of imperatives of reason. Thomas Nagel, Christine Korsgaard, and others (henceforth ‘rationalists’) have thereby sought to find an Achilles heel in the Humean position.2 Here I argue that the Motivation-byDesire Principle is not vulnerable to this attack. I first explain the objection, which focuses on the role of normative reasons in instrumental motivation, then examine the Davidsonian response analyzing reasons in terms of desires and beliefs, finding it 1 It is a matter of substantive dispute whether motivational explanations of action are causal explanations. I assume that the process of being motivated to act is a causal process, although I allow that some explanations in terms of motivation are constitutive rather than causal explanations. 2 Nagel 1970: 33-5, Korsgaard 1986: 12-13, 1997: 220-21, see also Scanlon 1998: 38, Smith 2004. For Korsgaard reason legislates these norms, whereas for Nagel, Scanlon and Smith it discovers them. Smith’s inclusion here may raise eyebrows, as he is considered the foremost champion of the Motivation-by-Desire Principle. But although Smith thinks the motivation to the means comes from a desire for the means, he argues that it must be practical reason and not desire for the end that generates this desire.