As long as you always have the option to exchange money for something useful (or at least know that you will have the possibility when you need it), you are indifferent between getting the item or money to buy the item.
I don’t think this works correctly… your agent has money and is standing next to a soda machine, getting progressively more thirsty. How does that trigger the exchange if you tie utility of money to utility of water to drink?
The thing to remember is that utility is what you use to push your utility maximizing agent around, to make the agent do things. The agent has some foresight of how it’s actions are going to affect future utility, and picks the actions that result in larger future utility. For human, the utility may be some integral of quality of life over the possible futures. Drinking water when thirsty, eating food when hungry, living in a better house vs living in a worse house, that sort of stuff. Use, not passive possession. If the agent has descendants, or cares for the mankind, then the integral may include other people.
If you include possession of money over time into this integral, your agent will make trade-offs between possession of the money and the ultimate total comfort of his life (and those he cares about). The agent’s behaviour will be that of a miser.
edit: and yes, as a heuristic, you can assign derived utilities to stuff that can be exchanged for usable stuff. But you can’t include those utilities in the sum over the original ones. The derived utilities are a shortcut, a heuristic, and one needs to be careful not to sum together utilities of different types.
edit: to think about it, though, maybe a great deal of people have the kind of utility that you described here, the utility calculated from possession of items. I, personally, try to act according to the utility as I described above, calculated from the uses and comfort of life.
to think about it, though, maybe a great deal of people have the kind of utility that you described here, the utility calculated from possession of items.
I think this is a key point. Our brains seem prone to a dynamic where we assign some attribute to our representation of a thing in a way that makes sense in the short term (e.g., valuing money), but we then fail to entirely re-initialize that assignment when we’re done doing whatever we were doing, so over time our instrumental goals take on a terminal value of their own. Theories involving clear-cut lines between terminal and instrumental goals consequently don’t describe actual human behavior terribly well.
Yes, absolutely. And I imagine that there’s a great variety in human behaviours. I don’t really assign utility to money, as much as foresee that more money allow for higher quality of life if certain conditions are met (and that involves ultimately exchanging the money for things, and the inclination to exchange is not a result of some very slight difference in ‘utility’ of possessions).
Consider playing chess… the effective chess program may assign some simplistic utilities to pieces and particular patterns, which it evaluates in the best-play-of-opponent near future states that it foresees.
It, however, does not do knight1.utility=(utility of victory); for some knight when that knight is critical for the inevitable checkmate (victory) it foresees. There’s no point in that, it’s going to use this knight correctly without that utility adjustment. If it would do that adjustment, it would have a bug when the checkmate involves sacrifice of that knight (or ‘exchange’ of that knight for a bishop). Some people may have that bug, some may not. I think it is better not to focus on how ‘people’ on average work but on the diversity of human behaviour and efficacy of different strategies.
your agent has money and is standing next to a soda machine, getting progressively more thirsty. How does that trigger the exchange if you tie utility of money to utility of water to drink?
In that case, he knows that at some time he has to buy water and a part of his money is equivalent to the soda. He is indifferent between buying it now and later (again assuming the machine works perfectly). When he begins to become thirsty, the utility of the soda increases and he will buy one.
But maybe there is an additional thing to consider: Time. Money is an option to get stuff in the future. Having money as an intermediate step is useful to have food/house/whatever later.
How can we define a single number for a utility, if we want to have food all the time? Maybe like this: Define a current utility density. Integrate the (expected) utility density over the lifetime. In that case, having money increases the expected utility density in the future, and therefore the total utility.
See, the core of the issue is that assigning some utility to money is just a heuristic. The foresight-oriented agent does not need to do that, for it automatically tries to acquire money (and trades wisely) when maximizing other utility such as e.g. quality of life over the future. Such agent, btw, would need to assign not utility number to the money, but the future utility distribution (at very least mean and standard deviation) that he expects to get from having the money at some point in closer future.
And with regards to assigning utilities from the future to the items in the now, well, chess AI doesn’t need to do that, it doesn’t need to have some floating point value for each piece and update those all the time. (see my chess example in another post).
The problem with assigning same type of utility to money as to the items those money buy, as per
In terms of “Hey, I have this nice-looking coin”, of course. But as you can buy items with money (and you know it), money has a comparable utility.
is that if you do so as you get thirstier, the utility of the coin should also increase.
The big issue here is that people speak very informally of the utilities all the time. We do, internally, distinguish between some derived utility (like that of money) and some primary utility (that of water when thirsty), at least to the extent necessary to avoid getting stuck when getting thirsty. Albeit it IS the case that some people act as misers, which is probably due to some confusion.
I don’t think this works correctly… your agent has money and is standing next to a soda machine, getting progressively more thirsty. How does that trigger the exchange if you tie utility of money to utility of water to drink?
The thing to remember is that utility is what you use to push your utility maximizing agent around, to make the agent do things. The agent has some foresight of how it’s actions are going to affect future utility, and picks the actions that result in larger future utility. For human, the utility may be some integral of quality of life over the possible futures. Drinking water when thirsty, eating food when hungry, living in a better house vs living in a worse house, that sort of stuff. Use, not passive possession. If the agent has descendants, or cares for the mankind, then the integral may include other people.
If you include possession of money over time into this integral, your agent will make trade-offs between possession of the money and the ultimate total comfort of his life (and those he cares about). The agent’s behaviour will be that of a miser.
edit: and yes, as a heuristic, you can assign derived utilities to stuff that can be exchanged for usable stuff. But you can’t include those utilities in the sum over the original ones. The derived utilities are a shortcut, a heuristic, and one needs to be careful not to sum together utilities of different types.
edit: to think about it, though, maybe a great deal of people have the kind of utility that you described here, the utility calculated from possession of items. I, personally, try to act according to the utility as I described above, calculated from the uses and comfort of life.
I think this is a key point. Our brains seem prone to a dynamic where we assign some attribute to our representation of a thing in a way that makes sense in the short term (e.g., valuing money), but we then fail to entirely re-initialize that assignment when we’re done doing whatever we were doing, so over time our instrumental goals take on a terminal value of their own. Theories involving clear-cut lines between terminal and instrumental goals consequently don’t describe actual human behavior terribly well.
Yes, absolutely. And I imagine that there’s a great variety in human behaviours. I don’t really assign utility to money, as much as foresee that more money allow for higher quality of life if certain conditions are met (and that involves ultimately exchanging the money for things, and the inclination to exchange is not a result of some very slight difference in ‘utility’ of possessions).
Consider playing chess… the effective chess program may assign some simplistic utilities to pieces and particular patterns, which it evaluates in the best-play-of-opponent near future states that it foresees.
It, however, does not do knight1.utility=(utility of victory); for some knight when that knight is critical for the inevitable checkmate (victory) it foresees. There’s no point in that, it’s going to use this knight correctly without that utility adjustment. If it would do that adjustment, it would have a bug when the checkmate involves sacrifice of that knight (or ‘exchange’ of that knight for a bishop). Some people may have that bug, some may not. I think it is better not to focus on how ‘people’ on average work but on the diversity of human behaviour and efficacy of different strategies.
If you don’t assign utility to money, you have to violate one of the rules given here: http://en.wikipedia.org/wiki/Utility#Additive_von_Neumann.E2.80.93Morgenstern_utility—or you have to take choices which do not maximize your utility.
But maybe there is an additional thing to consider: Time. Money is an option to get stuff in the future. Having money as an intermediate step is useful to have food/house/whatever later.
How can we define a single number for a utility, if we want to have food all the time? Maybe like this: Define a current utility density. Integrate the (expected) utility density over the lifetime. In that case, having money increases the expected utility density in the future, and therefore the total utility.
See, the core of the issue is that assigning some utility to money is just a heuristic. The foresight-oriented agent does not need to do that, for it automatically tries to acquire money (and trades wisely) when maximizing other utility such as e.g. quality of life over the future. Such agent, btw, would need to assign not utility number to the money, but the future utility distribution (at very least mean and standard deviation) that he expects to get from having the money at some point in closer future.
And with regards to assigning utilities from the future to the items in the now, well, chess AI doesn’t need to do that, it doesn’t need to have some floating point value for each piece and update those all the time. (see my chess example in another post).
The problem with assigning same type of utility to money as to the items those money buy, as per
is that if you do so as you get thirstier, the utility of the coin should also increase.
The big issue here is that people speak very informally of the utilities all the time. We do, internally, distinguish between some derived utility (like that of money) and some primary utility (that of water when thirsty), at least to the extent necessary to avoid getting stuck when getting thirsty. Albeit it IS the case that some people act as misers, which is probably due to some confusion.