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timtyler comments on Morality as Parfitian-filtered Decision Theory? - Less Wrong
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That seems to be of questionable relevance - since utilities in decision theory are all inside a single agent. Different agents having different values is not an issue in such contexts.
That's a big part of the problem right there: humans aren't "single agents" in this sense.
Humans are single agents in a number of senses - and are individual enough for the idea of revealed preference to be useful.
From the page you linked (emphasis added):
However, even if you ignore that, WARP is trivially proven false by actual human behavior: people demonstrably do sometimes choose differently based on context. That's what makes ordinal utilities a "spherical cow" abstraction.
(WARP's inapplicability when applied to real (non-spherical) humans, in one sentence: "I feel like having an apple today, instead of an orange." QED: humans are not "economic agents" under WARP, since they don't consistently choose A over B in environments where both A and B are available.)
The first sentence is true - but the second sentence doesn't follow from it logically - or in any other way I can see.
It is true that there are some problems modelling humans as von Neumann–Morgenstern agents - but that's no reason to throw out the concept of utility. Utility is a much more fundamental and useful concept.
WARP can't be used to predict a human's behavior in even the most trivial real situations. That makes it a "spherical cow" because it's a simplifying assumption adopted to make the math easier, at the cost of predictive accuracy.
That sounds to me uncannily similar to, "it is true that there are some problems modeling celestial movement using crystal spheres -- but that's no reason to throw out the concept of celestial bodies moving in perfect circles."
There is an obvious surface similarity - but so what? You constructed the sentence that way deliberately. You would need to make an analogy for arguing like that to have any force - and the required analogy looks like a bad one to me.
How so? I'm pointing out that the only actual intelligent agents we know of don't actually work like economic agents on the inside. That seems like a very strong analogy to Newtonian gravity vs. "crystal spheres".
Economic agency/utility models may have the Platonic purity of crystal spheres, but:
We know for a fact they're not what actually happens in reality, and
They have to be tortured considerably to make them "predict" what happens in reality.
It seems to me like arguing that we can't build a good computer model of a bridge - because inside the model is all bits, while inside the actual bridge is all spinning atoms.
Computers can model anything. That is because they are universal. It doesn't matter that computers work differently inside from the thing they are modelling.
Just the same applies to partially-recursive utility functions - they are a universal modelling tool - and can model any computable agent.
Not at all. I'm saying that just as it takes more bits to describe a system of crystal spheres to predict planetary motion than it does to make the same predictions with a Newtonian solar system model, so too does it take more bits to predict a human's behavior with a utility function, than it does to describe a human with interests and tolerances.
Indeed, your argument seems to be along the lines that since everything is made of atoms, we should model bridges using them. What were your words? Oh yes:
Right. That very universality is exactly what makes them a poor model of human intelligence: they don't concentrate probability space in the same way, and therefore don't compress well.
Sure - but whay you claimed was a "spherical cow" was "ordinal utilities" which is a totally different concept.
It was you who brought the revealed preferences into it, in order to claim that humans were close enough to spherical cows. I merely pointed out that revealed preferences in even their weakest form are just another spherical cow, and thus don't constitute evidence for the usefulness of ordinal utility.
That's treating the "Weak Axiom of Revealed Preference" as the "weakest form" of revealed preference. However, that is not something that I consider to be correct.
The idea I introduced revealed preference to support was that humans act like a single agent in at least one important sense - namely that they have a single brain and a single body.
Single brain and body doesn't mean anything when that brain is riddled with sometimes-conflicting goals... which is precisely what refutes WARP.
(See also Ainslie's notion of "picoeconomics", i.e. modeling individual humans as a collection of competing agents -- which is closely related to the tolerance model I've been giving examples of in this thread.)