You’re right that insofar as the utility function of the my future self is the same as my current utility function, I should want to maximize the utility of my future self. But my point with that statement is precisely that one’s future self can have very different interests that one’s current self, as you said (hence, the heroin addict example EDIT: Just realized I deleted that from the prior post! Put back in at the bottom of this one!).
Many (or arguably most) actions we perform can be explained (rationally) only in terms of future benefits. Insofar as my future self just is me, there’s no problem at all. It is MY present actions are maximizing MY utility (where actions are present, and utility not necessarily indexed by time, and if it is indexed by time, not by reference to present and future selves, just to ME). I take something like that to be the everyday view of things. There is only one utility function, though it might evolve over time
(the evolution brings about its own complexities. If a 15 year old who dislikes wine is offered a $50,000 bottle of wine for $10, to be given to him when he is 30, should he buy the wine? Taking a shortsighted look, he should turn it down. But if he knows by age 30 he’s going to be a wine connoisseur, maybe he should buy it after all cause it’s a great deal).
However, on the view brought up by Phil, that an expected utility function is definied over many different future selves, who just are many different people, you have to make things more complicated (or at the very least, we’re on the edge of having to complicate things). Some people will argue that John age 18, John age 30, and John age 50 are three completely different people. On this view, it is not clear that John age 18 rationally ought to perform actions that will make the lives of Johns age 30⁄50 better (at little detriment to his present day). On the extreme view, John’s desire to have a good job at age 30 does not provide a reason to go college—because John 18 will never be 30, some other guy will reap the benefits (admittedly, John likely receives some utility from the deceived view that he is progressing toward his goal; but then progression, not the goal itself, is the end that rationalizes his actions). Unless you establish an utilitarian or altruistic rational norm, etc., the principles of reason do not straightforwardly tell us to maximize other peoples utilities.
The logic naturally breaks apart even more when we talk about many possible John age 30s, all of whom live different quite different lives and are not the same agent at all as John age 18. It really breaks down if John age 18 + 1 second is not the same as John age 18. (On a short time scale, very few actions, if any, derive immediate utility. e.g. I flip the light swich to turn on the light, but there is at least a milisecond between performing the basic action and the desired effect occurring).
Which is why, if many of our actions are to make rational sense, an agent’s identity has to be maintained through time...at least in some manner. And that’s all I really wanted establish, so as to show that the utilities in an expected utility calculation are still indexed to an individual, not a collection of people that have nothing to do with each other (maybe John1, John2, etc are slightly different—but not so much as John1 and Michael are). However, if someone wants to take the view that John age 18 and John age 18 + 1s are as different as John and Michael, I admittedly can’t prove that someone wrong.
EDIT: Heroin example: sorry for any confusion
you are having surgery tomorrow. There’s a 50% chance that (a) you will wake up with no regard for former interests and relationships, and hopelessly addicted to heroin. There’s a 50% chance that (b) you will wake up with no major change to your personality. You know that in (a) you’ll be really happy if you come home from surgery to a pile full of heroin. And in (b) if you come home and remember that you wasted your life savings on heroin, you will only be mildly upset.
In order to maximize the expected utility of the guy who’s going to come out of surgery, you should go out and buy all of the heroin you can (and maybe pay someone to prevent you from ODing). But it’s by no means clear that you rationally ought to do this. You are trying to maximize your utility. Insofar as you question whether or not the heroin addict in (a) counts as yourself, you should minimize the importance of his fate in your expected utility calculation. Standing here today, I don’t care what that guy’s life is like, even if it is my physical body. I would rather make the utility of myself in (b) slightly higher, even at the risk of making the utility of the person in (a) significantly lower.
Many (or arguably most) actions we perform can be explained (rationally) only in terms of future benefits.
Mostly true, but Newcomb-like problems can muddy this distinction.
There is only one utility function, though it might evolve over time
No, it can’t. If the same utility function can “evolve over time”, it’s got type (Time → Outcome → Utilons), but a utility function just has type (Outcome → Utilons).
Unless you establish an utilitarian or altruistic rational norm, etc., the principles of reason do not straightforwardly tell us to maximize other peoples utilities.
Agreed. The same principle applies to the utility of future selves.
It really breaks down if John age 18 + 1 second is not the same as John age 18.
No, it really doesn’t. John age 18 has a utility function that involves John age 18 + 1 second, who probably has a similar utility function. Flipping the light grants both of them utility.
Insofar as you question whether or not the heroin addict in (a) counts as yourself, you should minimize the importance of his fate in your expected utility calculation.
I don’t see how this follows. The importance of the heroin addict in my expected utility calculation reflects my values. Identity is (possibly) just another factor to consider, but it has no intrinsic special privilege.
I would rather make the utility of myself in (b) slightly higher, even at the risk of making the utility of the person in (a) significantly lower.
That may be, but your use of the word “utility” here is confusing the issue. The statement “I would rather” is your utility function. When you speak of “making the utiity of (b) slightly higher”, then I think you can only be doing so because “he agrees with me on most everything, so I’m actually just directly increasing my own utility” or because “I’m arbitrarily dedicating X% of my utility function to his values, whatever they are”.
You’re right that insofar as the utility function of the my future self is the same as my current utility function, I should want to maximize the utility of my future self. But my point with that statement is precisely that one’s future self can have very different interests that one’s current self, as you said (hence, the heroin addict example EDIT: Just realized I deleted that from the prior post! Put back in at the bottom of this one!).
Many (or arguably most) actions we perform can be explained (rationally) only in terms of future benefits. Insofar as my future self just is me, there’s no problem at all. It is MY present actions are maximizing MY utility (where actions are present, and utility not necessarily indexed by time, and if it is indexed by time, not by reference to present and future selves, just to ME). I take something like that to be the everyday view of things. There is only one utility function, though it might evolve over time
(the evolution brings about its own complexities. If a 15 year old who dislikes wine is offered a $50,000 bottle of wine for $10, to be given to him when he is 30, should he buy the wine? Taking a shortsighted look, he should turn it down. But if he knows by age 30 he’s going to be a wine connoisseur, maybe he should buy it after all cause it’s a great deal).
However, on the view brought up by Phil, that an expected utility function is definied over many different future selves, who just are many different people, you have to make things more complicated (or at the very least, we’re on the edge of having to complicate things). Some people will argue that John age 18, John age 30, and John age 50 are three completely different people. On this view, it is not clear that John age 18 rationally ought to perform actions that will make the lives of Johns age 30⁄50 better (at little detriment to his present day). On the extreme view, John’s desire to have a good job at age 30 does not provide a reason to go college—because John 18 will never be 30, some other guy will reap the benefits (admittedly, John likely receives some utility from the deceived view that he is progressing toward his goal; but then progression, not the goal itself, is the end that rationalizes his actions). Unless you establish an utilitarian or altruistic rational norm, etc., the principles of reason do not straightforwardly tell us to maximize other peoples utilities.
The logic naturally breaks apart even more when we talk about many possible John age 30s, all of whom live different quite different lives and are not the same agent at all as John age 18. It really breaks down if John age 18 + 1 second is not the same as John age 18. (On a short time scale, very few actions, if any, derive immediate utility. e.g. I flip the light swich to turn on the light, but there is at least a milisecond between performing the basic action and the desired effect occurring).
Which is why, if many of our actions are to make rational sense, an agent’s identity has to be maintained through time...at least in some manner. And that’s all I really wanted establish, so as to show that the utilities in an expected utility calculation are still indexed to an individual, not a collection of people that have nothing to do with each other (maybe John1, John2, etc are slightly different—but not so much as John1 and Michael are). However, if someone wants to take the view that John age 18 and John age 18 + 1s are as different as John and Michael, I admittedly can’t prove that someone wrong.
EDIT: Heroin example: sorry for any confusion
you are having surgery tomorrow. There’s a 50% chance that (a) you will wake up with no regard for former interests and relationships, and hopelessly addicted to heroin. There’s a 50% chance that (b) you will wake up with no major change to your personality. You know that in (a) you’ll be really happy if you come home from surgery to a pile full of heroin. And in (b) if you come home and remember that you wasted your life savings on heroin, you will only be mildly upset.
In order to maximize the expected utility of the guy who’s going to come out of surgery, you should go out and buy all of the heroin you can (and maybe pay someone to prevent you from ODing). But it’s by no means clear that you rationally ought to do this. You are trying to maximize your utility. Insofar as you question whether or not the heroin addict in (a) counts as yourself, you should minimize the importance of his fate in your expected utility calculation. Standing here today, I don’t care what that guy’s life is like, even if it is my physical body. I would rather make the utility of myself in (b) slightly higher, even at the risk of making the utility of the person in (a) significantly lower.
Mostly true, but Newcomb-like problems can muddy this distinction.
No, it can’t. If the same utility function can “evolve over time”, it’s got type (Time → Outcome → Utilons), but a utility function just has type (Outcome → Utilons).
Agreed. The same principle applies to the utility of future selves.
No, it really doesn’t. John age 18 has a utility function that involves John age 18 + 1 second, who probably has a similar utility function. Flipping the light grants both of them utility.
I don’t see how this follows. The importance of the heroin addict in my expected utility calculation reflects my values. Identity is (possibly) just another factor to consider, but it has no intrinsic special privilege.
That may be, but your use of the word “utility” here is confusing the issue. The statement “I would rather” is your utility function. When you speak of “making the utiity of (b) slightly higher”, then I think you can only be doing so because “he agrees with me on most everything, so I’m actually just directly increasing my own utility” or because “I’m arbitrarily dedicating X% of my utility function to his values, whatever they are”.