Wednesday, October 14, 2009

Smith on Parfit: 11 of 15: No Beliefs Entail a Desire

In this series of posts I am commenting on an article sent to me by a member of the studio audience. These are, in a sense, notes written in the margin as it were as I highlight passages in the article and explain my agreement or disagreement.

I am looking at some principles of what reason is thought to require that Smith presented in the article. In Part 8, I argued that a desire-as-end that P and a belief that bringing about Q will bring about P only generates a belief in a desire-as-means that Q. An actual desire-as-means that Q requires that the belief is true.

Another principle that Smith mentions is:

[There exists a belief and a desire such that, if] someone believes that p, then she has an intrinsic desire that q.

Elsewhere, Smith quotes Parfit in making a relevantly similar claim.

According to [one] group of theories, reasons for acting are all provided by the facts that make certain things worth doing for their own sake, or make certain outcomes worth producing or preventing.


No belief entails a desire.

I discussed this earlier in discussing the first of these principles that a desire that p and a belief that bringing about q will bring about p implies a desire that q.

I said that this is the case. An end-desire that p combined with the belief that bringing about q will bring about p implies the belief that one has a means-desire to bring about q . . . a belief that can be as mistaken as the belief that brining about q will bring about p.

At the same time, an end-reason to bring about p combined with the fact that bringing about q will bring about p implies having a means-reason to bring about q. However, the means-value of q can remain unknown.

That was just a specific application of the principle that no belief entails a desire. Beliefs are motivationally neutral records of how the world is. Desires are motivationally potent records of how one wants to be. Deriving a motivationally potent state from a motivationally unnert state requires some explaining.

It is in this that I find the a grain of truth in David Hume's claim that one cannot derive an ought from an is. While I hold that moral facts can be derived from physical facts, those physical facts have to contain at least one reason for action. Otherwise, the moral conclusion cannot sensibly contain and ought. I do hold that an ought conclusion requires one or more reasons for action in the premises. Since desires are the only reasons for action that exist, an ought conclusion requires the mention of one or more desires in the premises.

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