In the VNM-sense, it may well be that technically humans don’t have a (VNM!)utility function. But meh, unless there’s uncomputable magic in there somewhere some kind of function mapping all possible stimuli to a human’s behavior should theoretically exist, and I’d call that utility function.
Calling it a utility function does not make it a utility function. A utility function maps decisions to utilities, in an entity which decides among its available choices by evaluating that function for each one and making the decision that maximises the value. Or as Wikipedia puts it, in what seems a perfectly sensible summary definition covering all its more detailed uses, utility is “the (perceived) ability of something to satisfy needs or wants.” That is the definition of utility and utility functions; that is what everyone means by them. It makes no sense to call something completely different by the same name in order to preserve the truth of the sentence “humans have utility functions”. The sentence has remained the same but the proposition it expresses has been changed, and changed into an uninteresting tautology. The original proposition expressed by “humans have utility functions” is still false, or if one is going to argue that it is true, it must be done by showing that humans have utility functions in the generally understood meaning of the term.
some kind of function mapping all possible stimuli to a human’s behavior should theoretically exist
No, it should not; it cannot. Behaviour depends not only on current stimuli but the human’s entire past history, internal and external. Unless you are going to redefine “stimuli” to mean “entire past light-cone” (which of course the word does not mean) this does not work. Furthermore, that entire past history is also causally influenced by the human’s behaviour. Such cyclic patterns of interaction cannot be understood as functions from stimulus to response.
In order to arrive at this subjectively ineluctable (“meh, unless there’s uncomputable magic”) statement, you have redefined the key words to make them mean what no-one ever means by them. It’s the Texas Sharpshooter Utility Function fallacy yet again: look at what the organism does, then label that as having higher “utility” than the things it did not do.
Mostly, I’m concerned that “strictly speaking, humans don’t have VNM-utility functions, so that’s that, full stop” can be interpreted like a stop sign, when in fact humans do have preferences (clearly) and do tend to choose actions to try to satisfice those preferences at least part of the time. To the extent that we’d deny that, we’d deny the existence of any kind of “agent” instantiated in the physical universe. There is predictable behavior for the most part, which can be modelled. And anything that can be computationally modelled can be described by a function. It may not have some of the nice VNM properties, but we take what we can get.
If there’s a more applicable term for the kind of model we need (rather than simply “utility function in a non-VNM sense”), by all means, but then again, “what’s in a name” …
Calling it a utility function does not make it a utility function. A utility function maps decisions to utilities, in an entity which decides among its available choices by evaluating that function for each one and making the decision that maximises the value. Or as Wikipedia puts it, in what seems a perfectly sensible summary definition covering all its more detailed uses, utility is “the (perceived) ability of something to satisfy needs or wants.” That is the definition of utility and utility functions; that is what everyone means by them. It makes no sense to call something completely different by the same name in order to preserve the truth of the sentence “humans have utility functions”. The sentence has remained the same but the proposition it expresses has been changed, and changed into an uninteresting tautology. The original proposition expressed by “humans have utility functions” is still false, or if one is going to argue that it is true, it must be done by showing that humans have utility functions in the generally understood meaning of the term.
No, it should not; it cannot. Behaviour depends not only on current stimuli but the human’s entire past history, internal and external. Unless you are going to redefine “stimuli” to mean “entire past light-cone” (which of course the word does not mean) this does not work. Furthermore, that entire past history is also causally influenced by the human’s behaviour. Such cyclic patterns of interaction cannot be understood as functions from stimulus to response.
In order to arrive at this subjectively ineluctable (“meh, unless there’s uncomputable magic”) statement, you have redefined the key words to make them mean what no-one ever means by them. It’s the Texas Sharpshooter Utility Function fallacy yet again: look at what the organism does, then label that as having higher “utility” than the things it did not do.
I appreciate your point.
Mostly, I’m concerned that “strictly speaking, humans don’t have VNM-utility functions, so that’s that, full stop” can be interpreted like a stop sign, when in fact humans do have preferences (clearly) and do tend to choose actions to try to satisfice those preferences at least part of the time. To the extent that we’d deny that, we’d deny the existence of any kind of “agent” instantiated in the physical universe. There is predictable behavior for the most part, which can be modelled. And anything that can be computationally modelled can be described by a function. It may not have some of the nice VNM properties, but we take what we can get.
If there’s a more applicable term for the kind of model we need (rather than simply “utility function in a non-VNM sense”), by all means, but then again, “what’s in a name” …