It’s somewhat less constructive than reinventing the wheel, actually. It’s axiomatic, not empirical.
The whole von Neumann-Morgenstern edifice (which is roughly what Psy-Kosh seems to be reconstructing in a roundabout way) is axiomatic. That doesn’t make it worthless.
assigning utilities to different outcomes such that they maintain preference ranking …could be done about as well with [the assumption that] all outcomes can be mapped to discrete util values.
Well, yes. You can derive X from the assumption that X is true, but that doesn’t seem very productive. (I didn’t think Psy-Kosh claimed, or needs to claim (yet), that all utils are measured on the same scale, but I could be wrong. Not least because that statement could mean a variety of different things, and I’m not sure which one you intend.)
Only some preference orderings can be represented by a real-valued utility functions. Lexicographic preferences, for example, cannot. Nor can preferences which are, in a particular sense, inconsistent (e.g. cyclic preferences).
My sense is that Psy-Kosh is trying to establish something like a cardinally measurable utility function, on the basis of preferences over gambles. This is basically what vNM did, but (a) as far as I can tell, they imposed more structure on the preferences; (b) they didn’t manage to do it without using probabilities; and (c) there’s a debate about the precise nature of the “cardinality” they established. The standard position, as I understand it, is that they actually didn’t establish cardinality, just something that looks kind of like it.
Intuitively, the problem with the claim that utility “indices actually correspond[] in a meaningful way to how much you prefer one thing to another” is that you could be risk-averse, or risk-loving with respect to welfare, and that would break the correspondence. (Put another way: the indices correspond to how much you prefer one thing to another adjusted for risk—not how much you prefer one thing to another simpliciter.)
Yeah. Here I’m trying to actually justify the existence of a numbering scheme that has the property that “increase of five points of utility is increase of five points of utility (in some set of utility units)”, no matter what the state that you’re starting and increasing from is.
I need to do this so that I then have a currency I can use in a dutch book style argument to build up the rest of it.
As far as Lexicographic preferences, I had to look that up. Thanks, that’s interesting. Maybe doable with hyperreals or such?
As far as risk aversion, um… unless I misunderstand your meaning, that should be easily doable. Simply have really increasingly huge steps of disutiliy as one goes down the preference chain, so even slight possibility of a low rank outcome would be extremely unpreferred?
I’m afraid all of this is all still a bit vague for me, sorry.
Are you familiar with the standard preference representation results in economics (e.g. the sort you’d find in a decent graduate level textbook)? The reason I ask is that the inability to represent lexicographic preferences is pretty well-known, and the fact that you weren’t aware of it makes me suspect even more strongly than before that you may be trying to do something that’s already been done to death without realizing it.
I think we’re talking past each other on the risk aversion front. Probably my fault, as my comment was somewhat vague. (Maybe also an issue of inferential distance.)
More I think about it though, seems like hyperreals, now that I know of them, would let one do a utility function for lexicographic preferences, no?
And nothing for you to apologize for. I mean, if there’s this much confusion about what I’m writing, it seems likely that the problem is at my end. (And I fully admit, there’s much basic material I’m unfamiliar with)
My criticism may be more of the writing than the concept. Once you establish that utilities obey a >=< relationship with one another, all these properties seem to flow rather cleanly and easily. If there’s one thing I’ve learned from philosophy, it’s that you should always be wary of someone who uses a thousand words when a hundred will do.
The properties are interesting and useful, it just seems that the explanation of them is being dragged out to make the process look both more complex and more “objective” than it really is, and that’s what I’m wary of.
The whole von Neumann-Morgenstern edifice (which is roughly what Psy-Kosh seems to be reconstructing in a roundabout way) is axiomatic. That doesn’t make it worthless.
Well, yes. You can derive X from the assumption that X is true, but that doesn’t seem very productive. (I didn’t think Psy-Kosh claimed, or needs to claim (yet), that all utils are measured on the same scale, but I could be wrong. Not least because that statement could mean a variety of different things, and I’m not sure which one you intend.)
Only some preference orderings can be represented by a real-valued utility functions. Lexicographic preferences, for example, cannot. Nor can preferences which are, in a particular sense, inconsistent (e.g. cyclic preferences).
My sense is that Psy-Kosh is trying to establish something like a cardinally measurable utility function, on the basis of preferences over gambles. This is basically what vNM did, but (a) as far as I can tell, they imposed more structure on the preferences; (b) they didn’t manage to do it without using probabilities; and (c) there’s a debate about the precise nature of the “cardinality” they established. The standard position, as I understand it, is that they actually didn’t establish cardinality, just something that looks kind of like it.
Intuitively, the problem with the claim that utility “indices actually correspond[] in a meaningful way to how much you prefer one thing to another” is that you could be risk-averse, or risk-loving with respect to welfare, and that would break the correspondence. (Put another way: the indices correspond to how much you prefer one thing to another adjusted for risk—not how much you prefer one thing to another simpliciter.)
Yeah. Here I’m trying to actually justify the existence of a numbering scheme that has the property that “increase of five points of utility is increase of five points of utility (in some set of utility units)”, no matter what the state that you’re starting and increasing from is.
I need to do this so that I then have a currency I can use in a dutch book style argument to build up the rest of it.
As far as Lexicographic preferences, I had to look that up. Thanks, that’s interesting. Maybe doable with hyperreals or such?
As far as risk aversion, um… unless I misunderstand your meaning, that should be easily doable. Simply have really increasingly huge steps of disutiliy as one goes down the preference chain, so even slight possibility of a low rank outcome would be extremely unpreferred?
I’m afraid all of this is all still a bit vague for me, sorry.
Are you familiar with the standard preference representation results in economics (e.g. the sort you’d find in a decent graduate level textbook)? The reason I ask is that the inability to represent lexicographic preferences is pretty well-known, and the fact that you weren’t aware of it makes me suspect even more strongly than before that you may be trying to do something that’s already been done to death without realizing it.
I think we’re talking past each other on the risk aversion front. Probably my fault, as my comment was somewhat vague. (Maybe also an issue of inferential distance.)
More I think about it though, seems like hyperreals, now that I know of them, would let one do a utility function for lexicographic preferences, no?
And nothing for you to apologize for. I mean, if there’s this much confusion about what I’m writing, it seems likely that the problem is at my end. (And I fully admit, there’s much basic material I’m unfamiliar with)
My criticism may be more of the writing than the concept. Once you establish that utilities obey a >=< relationship with one another, all these properties seem to flow rather cleanly and easily. If there’s one thing I’ve learned from philosophy, it’s that you should always be wary of someone who uses a thousand words when a hundred will do.
The properties are interesting and useful, it just seems that the explanation of them is being dragged out to make the process look both more complex and more “objective” than it really is, and that’s what I’m wary of.