Consider the following example from Parfit’s Reasons and Persons:
When I was young what I most wanted was to be a poet. This desire was not conditional on its own persistence. I did not want to be a poet only if this would later still be what I wanted. Now that I am older, I have lost this desire. I have changed my mind in the more restricted sense that I have changed my intentions. But I have not decided that poetry is in any way less important or worthwhile. Does my past desire give me a reason to try to write poems now, though I now have no desire to do so? (1984, 157)
The answer is clearly “no.” Parfit’s past desire to become a poet doesn’t give him any reason to write poems now. And, from this, we can conclude that the fulfillment of his past desire to be a poet is of no benefit to him, for it is plausible to suppose that if the fulfillment of his past desire were beneficial, he would have a reason to write poems. But can we further conclude that, in general, the fulfillment of a past desire is not, itself, beneficial? — see note 1 below.
As Steve Luper rightly points out in his forthcoming paper “Past Desires and the Dead,” the answer is “no,” for there is more than one possible explanation for why Parfit wouldn’t benefit from writing poetry now that he has no desire to do so. One explanation is that it is the “pastness” of his desire that undermines what prudential value there might otherwise have been in satisfying it. But another explanation points to the process by which Parfit’s desire has come to past and whether that process is something that Parfit would have opposed. Luper claims that although a desire doesn’t always lose its prudential significance when it is removed, it does always lose its prudential significance when it is given up or removed voluntarily (i.e., given up or removed by a process that one would not oppose) — see note 2 below. So Luper believes that what explains the fact that Parfit would not benefit from satisfying his past desire is that his desire has been voluntarily given up. Furthermore, Luper claims that the non-fulfillment of a past desire that has been involuntarily removed can be harmful. By contrast, I believe that the non-fulfillment of a past desire is never, itself, harmful and that the best explanation for why Parfit would not benefit from satisfying his past desire by writing poetry is that his desire has come to past, not that it has come to past by a process that Parfit would not oppose. So who’s right, me or Luper?
To determine which of us has the better explanation for why Parfit doesn’t harm himself in choosing not to write poetry, let’s consider a variant of Parfit’s original case. Suppose that, unbeknownst to Parfit, Dr. Evil has been slipping a drug into Parfit’s morning tea and that this drug has caused Parfit’s interest in poetry to wane, allowing his interest in philosophy to wax. Eventually, as a result of the drug, Parfit has lost all desire to be a poet. And let’s assume that Parfit would oppose this type of external manipulation of his desires. Now the question is: Is the fulfillment of his past desire to be a poet of any prudential importance? In other words, does his failure to write poetry now harm him by making it the case that his past desire to be a poet will never be fulfilled? My inclination is to say “no.” Of course, I might want to say that Dr. Evil harmed Parfit in giving him the drug, for Dr. Evil thereby violated his autonomy. And I might want to say that if Parfit would have been happier being a poet as opposed to the philosopher that he is now, then Dr. Evil harmed him by causing him to be less happy than he would have otherwise been. But I would deny that Parfit is harmed by the non-fulfillment of his past desire to be a poet, despite the fact that his desire was removed by involuntary external manipulation. Unfortunately, I have no argument for this. It’s just a brute intuition. So I’m curious whether others share my intuition. For if my intuition is correct, then we should, contrary to Luper, hold that the non-fulfillment of a past desire is of no prudential importance whether or not it has come to past as a result of a process that one would oppose.
Note 1: It could be that doing what will satisfy a past desire is beneficial, as where the fulfillment of one’s present desires is beneficial and one presently desires to do something that will satisfy this past desire. But this is not a case where the fulfillment of the past desire is, itself, beneficial. It is the fulfillment of the present desire that is beneficial.
Note 2: As Luper points out, we don’t disapprove of our desires changing, say, as a result of rational deliberation or as a result of an unmanipulated shift in our concerns from one valuable thing to another. But we do disapprove of our desires changing as a result of involuntary external manipulation (e.g., brainwashing). And when it comes to certain desires (e.g., one’s desire to do philosophy as opposed to one’s desire to smoke cigarettes), many of us would oppose someone else giving us a drug to remove the desire.