Monday, May 1, 2017

Desire-belief theory and soft determinism

Consider this naive argument:

  1. If the desire-belief theory of motivation is true, whenever I act, I do what I want.
  2. Sometimes in acting I do what I do not want.
  3. So the desire-belief theory is false.

Some naive arguments are nonetheless sound. (“I know I have two hands, …”) But that’s not where I want to take this line of thought, though I could try to.

I think there are two kinds of answers to this naive argument. One could simply deny (2), espousing an error theory about what happens when people say “I did A even though I didn’t want to.” But suppose we want to do justice to common sense. Then we have to accept (2). And (1) seems to be just a consequence of the desire-belief theory. So what to can one say?

Well, one can say that “what I want” is used in a different sense in (1) and (2). The most promising distinction here seems to me to be between what one wants overall and what one has a desire for. The desire-belief theorist has to affirm that if I do something, I have a desire for it. But she doesn’t have to say that I desire the thing overall. To make use of this distinction, (2) has to say that I act while doing what I do not overall want.

If this is the only helpful distinction here, then someone who does not want to embrace an error theory about (2) has to admit that sometimes we act not in accord with what we overall want. Moreover, it seems almost as much a truism as (2) that:

  1. Sometimes in acting freely I do what I do not want.

On the present distinction, this means that sometimes in acting freely, I do something that isn’t my overall desire.

But this in turn makes soft determinism problematic: for if my action is determined and isn’t what I overall desire, and desire-belief theory is correct, then it is very hard to see how the action could possibly be free.

There is a lot of argument from ignorance (the only relevant distinction seems to be…, etc.) in the above. But if it can be all cashed out, then we have a nice argument that one shouldn’t be both a desire-belief theorist or a soft-determinist. (I think one shouldn’t be either!)


Samarpan Thorat said...

Very Nice Article

God bless you.

Heath White said...

I think there is an equivocation but a different one. In the DB theory, "desire" means something like pure motivation, oomph. (It's questionable then whether we have a *theory* of motivation, but leave that aside.) In the "sometimes I do what I don't want to do" it means, or includes the idea of, pleasure, attraction, appeal. As in, "Sometimes I do what I have to do, or ought to do, rather than what I want to do." And sometimes you do it freely.

Personally I think the idea of a theory of motivation, in intentional psychological terms, is not that promising. What there is, is a theory of practical reasons. The motivation usually but not always follows along, and the reasons for *that* are not intentional explanations.