I wrote recently about the strange relationship a person might have with his future selves. What if Noko (n) eats salad for dinner today to try to lose five pounds, and Noko (n+1) sabotages her efforts by ordering the creme brulee tomorrow? What if Noko (n+12) doesn't appreciate our efforts?
But, of course, we worry about our future selves, too. Constantly. Will they have enough money to retire on? Will they be healthy? Will they be suffering at next Tuesday's dentist appointment?
So. Why do we worry about our future selves? And how much should we worry?
In last Sunday's Times, Jim Holt reflects on the analogy between worrying about future selves and worrying about actual other people. He says the reason we worry about our future selves is that our evolutionary ancestors worried about their future selves.
OK, sure. As philosophers say, that's an explanatory reason, of a sort. It explains why, in the course of things, we are a certain way. But it's not an justificatory reason. It's not even a satisfying explanatory reason, in a way. It leaves open the question: Are we right to care about our future selves? And if we are, what makes this make sense? An evolutionary answer isn't going to solve that problem.
The question is important, because without an explanation of why we ought to care about our future selves, how are we going to answer the question of how much we ought to care about our future selves?
I'm inclined to say that in a way the question of "why" has no satisfactory answer. You care about your future self because it's you: it's more like caring about your present self than caring about someone else. In that case, the question of "how much" has no satisfactory answer either.
Holt imagines a person who doesn't care about his future self as someone who is really improvident: never saving for the future, never preparing for what's going to happen.
But even a person who doesn't want to sacrifice for his future self might care about his future self; he just isn't motivated to give up what he has now. He might still dread the bad things that are going to happen. He just doesn't dread them enough.
So how much should you dread the bad things that may befall your future self? The background assumption seems to be something like this: you should dread them the same about you would dread similar suffering of your present self. Rationality, on this view, requires you to treat your future self and your present self the same.
This Freakonomics post by Daniel Hamermish uses the example of cheating on your spouse to illustrate the concept of "hyperbolic discounting": "people overemphasize current pleasure and pain in comparing actions at different points in time." This leads them to "irrational" behavior.
Hamermish allows that one might properly "discount" for something being in the future, but seems to suggest that cheating is discounting too much. Indeed, hyperbolically so.
So how much is the right amount?
When I was a kid, in like seventh grade, there was a poster on our classroom wall that had a quote from a poem -- something about how the author wanted to burn bright and short like a star rather than endure long and cold like a planet.
I remember I always thought it was the darndest thing to put up in a kids' classroom. After all, adults are always trying to get kids to do the exact opposite: Do your homework! Don't smoke! Care about your future selves, guys!
Inviting the classic teen response: Why should I?
Why indeed? Ya got me.