Most of our preferences, if fulfilled, make us better off, at least for the span of time before hedonic treadmilling claws the benefit back. If it is given that I am to have a bowl of ice cream tonight, and I prefer vanilla over chocolate, we would expect me to benefit more from a bowl of vanilla than from a bowl of chocolate.
But let’s say that I’m at a very odd ice cream shop and they have only two flavors left, neither which I’ve heard of before: fluzzleberry and kablazzo bean. Unbeknownst to me, I’ll like them equally, but I’m not allowed to sample, and so I flip a coin and end up with the kablazzo bean. I eat it and enjoy it, but I’m no better off than I would have been had the coin dictated the fluzzleberry.
We now change the scenario, renaming fluzzleberry to sufferberry. This time, the name “sufferberry” causes me to develop a preference for the kablazzo bean, even though my tastes and the ice creams have not changed at all. I order the kablazzo bean, eat it, and enjoy it, but my benefit is no greater in this second scenario than it was when sufferberry was called fluzzleberry.
A person’s preferences are usually good indicators of what would be best for that person, but creating a preference in someone and then fulfilling that preference without changing their actual benefit structure doesn’t make them better off.
When we create a desire in someone, we create a preference for something as well as some combination of a hunger and a drive to attain that object. This can be beneficial to the person if the desire increases the probability of their attaining the desideratum, and attaining the desideratum gives them a benefit — perhaps before desiring it they just didn’t have the energy to pursue the object, or they mistakenly thought it wouldn’t be worthwhile. But let’s assume that the person had sufficient energy and complete relevant knowledge, and correctly determined pre-desire that it wasn’t worth doing what they’d have to do to attain the object. In this case, unless we ensure that the person indeed attain the object, we do them a disservice. Creating a hunger in someone imposes a deficiency, and that deficiency is harmful until remedied. Indeed, even if they do attain the object and satisfy their hunger, they still were harmed for the period between the creation of the deficiency and the attainment of the desideratum.
To me at least, this still seems counterintuitive. That’s why I went through the ice cream thought experiment, to demonstrate that benefit need not depend on preference. Usually when we prefer something and have a hunger for it, it’s because we have reason to believe that getting it will bring us a benefit, and forgoing that benefit is painful. Beings that lacked the drive to attain good things for themselves would have been selected out in the course of evolution.
But sometimes our desires are unjustified. Inducing a desire in a child for a toy by advertising does the child no good unless the child would have actually been better off with the toy and the advertisement gave the child or its parents new information. And as adults, we’re hardly immune to the effects of advertising, now matter how much we’d like to believe. Our reason and prudence may promote in us desires for good things, but they are unreliable gatekeepers in preventing us from being planted with unhelpful desires. Our machinery of hunger and lust is operable by others who do not always have our best interests in mind.