Perplexed comments on Morality as Parfitian-filtered Decision Theory? - Less Wrong
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Comments (270)
Ah, "the advantage of theft over honest toil". Writing down a definite noun phrase does not guarantee the existence of a thing in reality that it names.
Some specific references would help in discerning what, specifically, you are alluding to here. You say in another comment in this thread:
but you have not done this at all, merely made vague allusions to "the last 150 years" and "standard economic game theory".
Well, you can't get much more standard than Von Neumann and Morgenstern's "Theory of Games and Economic Behaviour". This book does not attempt to justify the hypothesis that we maximise something when we make decisions. That is an assumption that they adopt as part of the customary background for the questions they want to address. Historically, the assumption goes back to the questions about gambling that got probability theory started, in which there is a definite thing -- money -- that people can reasonably be regarded as maximising. Splitting utility from money eliminates complications due to diminishing marginal utility of money. The Utility Theorem does not prove, or attempt to prove, that we are maximisers. It is a not very deep mathematical theorem demonstrating that certain axioms on a set imply that it is isomorphic to an interval of the real line. The hypothesis that human preferences are accurately modelled as a function from choices to a set satisfying those axioms is nowhere addressed in the text.
I shall name this the Utility Hypothesis. What evidence are you depending on for asserting it?
Sure. Happy to help. I too sometimes have days when I can't remember how to work that "Google" thing.
You mention Von Neumann and Morgenstern's "Theory of Games and Economic Behaviour" yourself - as you can see, I have added an Amazon link. The relevant chapter is #3.
Improvements to this version have been made by Savage and by Anscombe and Aumann. You can get a useful survey of the field from wikipedia. Wikipedia is an amazing resource, by the way. I strongly recommend it.
Two texts from my own bookshelf that contain expositions of this material are Chapter 1 of Myerson and Chapter 2 of Luce and Raiffa. I would recommend the Myerson. Luce and Raiffa is cheaper, but it is somewhat dated and doesn't prove much coverage at all of the more advanced topics such as correlated equilibria and the revelation principle. It does have some good material on Nash's program though.
And finally, for a bit of fun in the spirit of Project Steve, I offer this online bibliography of some of the ways this body of theory has been applied in one particular field.
Did I assert it? Where? I apologize profusely if I did anything more than to suggest that it provides a useful model for the more important and carefully considered economic decisions. I explicitly state here that the justification of the theory is not empirical. The theory is about rational decision making, not human decision making.
It is not. As I said, the authors do not attempt to justify the Utility Hypothesis, they assume it. Chapter 2 (not 3), page 8: "This problem [of what to assume about individuals in economic theory] has been stated traditionally by assuming that the consumer desires to obtain a maximum of utility or satisfaction and the entrepreneur a maximum of profits." The entire book is about the implications of that assumption, not its justificaation, of which it says nothing.
Neither do these authors attempt to justify the Utility Hypothesis; they too assume it. I can find Luce and Raiffa in my library and Myerson through inter-library loan, but as none of the first three works you've cited provide evidence for the claim that people have utility functions, rather than postulating it as an axiom, I doubt that these would either.
But now you deny having asserted any such thing:
Here you claim that people have utility functions:
And also here:
Here you assume that people must be talking about utility functions:
Referring to the message from which the last three quotes are taken, you say
and yet here you expand the phrase "prefer to assume" as :
These are weasel words to let you talk about utility functions while denying you think there are any such things.
How would you set about finding a model that is closer to reality, rather than one which merely makes better predictions?
I would undertake an arduous self-education in neuroscience. Thankfully, I have no interest in cognitive models which are close to reality but make bad predictions. I'm no longer as good at learning whole new fields as I was when I was younger, so I would find neuroscience a tough slog.