I am currently looking over the objections that Chris Heathwood A to a desire-fulfillment (or desire-satisfaction) theory of a good life.
(See: Desire Satisfaction and Hedonism by Chris Heathwood (Philosophical Studies (2006) 128:539–563).)
One of the problems he claims exists with such a theory concerns the possibility of irrational desires.
[A] person might know that going to the dentist is in his interest, but still he prefers and chooses not to go, because he is weak-willed. The claim is that desire satisfactionism implies, incorrectly, that since he desires not to go and all desire satisfactions are good for a person, it is good him not to go to the dentist.
The question is: What does it take to make a desire irrational?
I argue that an irrational desire is a desire that tends to thwart other desires of the agent. (An immoral desire is a desire that tends to thwart the desires of other agents.)
The desire to smoke is an irrational desire. It is a desire that tends to lead to future consequences that will thwart the desires that the agent can be expected to have at that time. All things considered, the agent would be better off not smoking. However, all things considered, the agent would be better off if she never acquired the desire to smoke.
The reason that irrational desires exist is that desires are not capable of backward causation. A future desire cannot influence present-day actions. When an agent acts, he only acts to fulfill the most and strongest of his current desires, given his beliefs. He never acts so as to fulfill a desire that does not yet exist - even if he knows that it will exist.
A person can know full well that a current desire (to smoke, to drink, to eat, to gamble, to use some cocaine, for sex, for pornography, to avoid public speaking, to avoid flying, to avoid germs) is excessive and will thwart many and strong future desires, and still succumb to that irrational desire. Because, while his beliefs about the relationship between acts motivated by current desires and the fulfillment of future desires are true, the future desires are also impotent.
When desires come into conflict, the next question that comes up is: Which desires should be changed? Which are the desires to be given up and which are to be kept?
Desire fulfillment theory says that malleable desires should be given up. It makes no sense to try to give up desires that are fixed. And, of malleable desires, those desires that are easiest to change should be changed in preference over those that are harder to change.
When we talk about irrational desires, we are not just talking about desires that are difficult to give up once they have been gotten, but desires that can be avoided in the first place. A fair amount of social morality goes into avoiding the acquisition of desires that tend to thwart other desires, because it is recognized that, once acquired, they cannot easily be unacquired.
It is a part of this theory that the fulfillment irrational desires count towards the quality of a life. After all, if we take that same desire and strip away the conflicts that make it irrational, we would also be taking away all reasons-for-action for avoiding that desire to begin with. Desires are the only reasons for action that exist, so the only reasons for action that exist for getting rid of an irrational desire are the desires that the irrational desire will thwart.
On this model, irrational desires do not provide a problem with a desire-fulfillment theory of value. Instead, a desire-fulfillment theory of value provides the best way of understanding irrational value.
It tells us what irrational desires are (malleable or avoidable desires that tend to thwart future desires).
It tells us how it is that irrational desires can exist (future desires have no backward causation so weaker current desires can cause actions that thwart many and strong future desires).
It tells us why irrational desires generally subtract from the quality of a life (because of the weight of the future desires that end up getting thwarted).