“The Humean Theory of Motivation Rejected” G. F. Schueler
Philosophy and Phenomenological Research, volume 78, number 1 (January 2009), pages 103-122.
Main authors discussed: Michael Smith, Donald Davidson, Phillip Pettit, Thomas Nagel
Schueler presents a dilemma for the defender of the Humean theory of motivation. First, let’s define the theory. Schueler focuses on the theory as one that explains why a person acted as she did and not as a theory of what a person ought to do (103). According to Schueler, contemporary advocates of the Humean theory, “…agree with Hume in holding that a desire or some analogous motivational state is always needed to move anyone to act” (105). His main example of a contemporary Humean theory of motivation is Michael Smith’s, according to which:
R at t constitutes a motivating reason of agent A to Φ if and only if there is some Ψ such that R at t consists of an appropriately related desire of A to Ψ and a belief that were she to Φ she would Ψ (106).
The first horn of the dilemma arises when we fill in the reason for the phrase “appropriately related to” in Smith’s formulation. Schueler argues that this phrase is necessary to avoid counter-examples in which a person does Φ, has a desire for Ψ, and a belief that if she were to Φ she would Ψ, and yet this particular belief-desire pair has nothing to do with the agent Φing. Schueler develops an example to make this clear. Suppose he knows that the bus that goes by his house goes to the University. One day when his car won’t start and he wants to get to the University, he gets on the bus. However, he got on the bus, not to get to the University, but rather to get to his sister’s office. There he plans to borrow her car and then drive to the University. The reason the belief-desire pair (“I want to get to the University” and “I believe this bus goes to the University”) does not explain his action is because they were not “put together” in the right way by him (108-9). It is analogous to something that happens in theoretical reasoning (107). Suppose someone has two beliefs that entail a third. This person comes to believe the third belief, not on the basis of the two that entail it, but because he heard a rumor that it might be true and he is easily swayed by rumors.
One lesson that Schueler takes from the bus example is that practical reasoning is an activity–it is not the mere presence of the belief-desire pair that explains behavior. Rather, the explanation of the behavior requires that the agent engage in practical reasoning in which the agent “puts them together” (109). But this causes a problem for the Humean. For if the explanation of the action traces back to the activity of an agent reasoning about beliefs and desires, then the actual desire is not what explains the action, and can, in fact, be dropped out of the explanation altogether (110). This is seen more clearly when we consider that an agent can be wrong about what she desires—when, for example, the agent believes she wants to Ψ but actually does not want to Ψ (111). In such a case, the desire to Ψ simply cannot explain what the agent does, for that desire does not exist. And yet, someone might mistakenly believe that she wants to Ψ, reason about how to satisfy this desire, and come to believe that if she were to Φ she would Ψ, and as a result of putting these two things together, Φ. What this shows us, argues Schueler, is that it is the representation of a desire to Ψ that is relevant in the explanation of the action and not the desire itself (112). According to Schueler, this first horn of the dilemma is not strong enough by itself to refute the Humean theory of motivation. But, the “putting together” point discussed here will be relevant when we move to the second horn of the dilemma.
The second horn focuses on the fact that from a phenomenological point of view our practical reasoning often does not take the form of explicitly reasoning about how to satisfy one of our desires. Instead, we often seem to reason about what to do based on what we find to be important, worth doing, or think we ought to do. These are not desires, and yet they are the sorts of the things we “put together” with beliefs in our practical deliberation (117).
Humeans, such as Smith and Pettit, are aware of this fact and respond by introducing the distinction between a desire that exists in the foreground and a desire that exists in the background of a decision. A desire that exists in the foreground of the decision is one that the agent is consciously aware that she has and is one that she is reasoning about how to satisfy. One that exists in the background helps to motivate the action, but the agent need not be aware that it is there–it is not one about which the agent is consciously reasoning. Smith and Pettit claim that the Humean can respond to the objection by claiming that in those cases in which it appears to us that we are not reasoning about how to satisfy one of our desires, we nevertheless have a background desire that is doing the motivational work (118).
Now we can see the dilemma clearly. To accommodate what seems to be an obvious point about the phenomenology of our practical deliberation, the Humean must claim that our desires that motivate us exist in the background. But to avoid counter-examples like the bus case, they must claim that the desires that motivate do not exist in the background. The Humean cannot have it both ways. According to Schueler, the best way to avoid this dilemma is to reject the Humean theory of motivation.
Reviewed by Scott Wilson
Wright State University
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