Papers framing anthropic questions as decision problems?

jsalvatier

A few weeks ago at a Seattle LW meetup, we were discussing the Sleeping Beauty problem and the Doomsday argument. We talked about how framing Sleeping Beauty problem as a decision problem basically solves it and then got the idea of using same heuristic on the Doomsday problem. I think you would need to specify more about the Doomsday setup than is usually done to do this.

We didn't spend a lot of time on it, but it got me thinking: Are there papers on trying to gain insight into the Doomsday problem and other anthropic reasoning problems by framing them as decision problems? I'm surprised I haven't seen this approach talked about here before. The idea seems relatively simple, so perhaps there is some major problem that I'm not seeing.

Stuart, thanks for contributing here. I've posted a couple of discussion threads myself on anthropic reasoning and the Doomsday Argument, and your paper has been mentioned in them, which caused me to read it.

I'm interested how you would like to apply ADT in Big World cases, where e.g. there are infinitely many civilizations of observers. Some of them expand off their home planets, others don't, and we are trying to estimate the fraction (limiting frequency) of civilizations that expand, when conditioning on the indexical evidence that we're now living on our home planet. It seems to me that aggregate utility functions (either "selfless" or additive utility altruist) won't give sensible results here - you just end up comparing infinity against infinity and can't make decisions. Whereas "selfish" or average utility altruist functions will give Doomish conclusions, for the reasons discussed in your paper.

See http://lesswrong.com/lw/9ma/selfindication_assumption_still_doomed/ and in particular my recent questions to endoself here http://lesswrong.com/lw/9ma/selfindication_assumption_still_doomed/6gaq

I'm genuinely interested in how different Decision Theories handle the updating in the infinite case (or if there is no formal updating, how the agents bet at different stages).

A final thing is that I'm puzzled by your claim that selfish and average utility altruist agents won't care about Doom, and so it won't affect their decisions. Won't average utilitarians worry about the negative utility (pain, distress) of agents who are going to face Doom, and consider actions which will mitigate that pain? Won't selfish agents worry about facing Doom themselves, and engage in survivalist "prepping" (or if that's going to be no use at all, party like there's no tomorrow)?

I'm interested how you would like to apply ADT in Big World cases, where e.g. there are infinitely many civilizations of observers.

I don't know how to deal with infinite ethics, and I haven't looked into that in detail. ADT was not designed with that in mind, and I think we must find specific ways of extending these types of theories to infinite situations. And once they are found, we can apply them to ADT (or to other theories).

Though on a person note, I have to say that non-standard reals are cool.

0Stuart_Armstrong14y

I was simplifying when I said "didn't care". And if there's negative utility around, things are different (I was envisaging the doomsday scenario as something along the lines of painless universal sterility). But let's go with your model, and say that doomsday will be something painful (slow civilization collapse, say). How will average and total altruists act? Well, an average altruist would not accept an increase in the risk of doom in exchange for other gains. The doom is very bad, and would mean a small population, so the average badness is large. Gains in the case where doom doesn't happen would be averaged over a very large population, so would be less significant. The average altruist is willing to sacrifice a lot to avoid doom (but note this argument needs doom=small population AND bad stuff). What about the total altruist? Well, they still don't like the doom. But for them the benefits in the "no doom" scenario are not diluted. They would be willing to run a slight increase in the risk of doom, in exchange of some benefit to a lot of people in the no-doom situation. They would turn on the reactor that could provide limitless free energy to the whole future of the human species, even if there was small risk of catastrophic meltdown. So the fact these two would reason differently is not unexpected. But what I'm trying to get to is that there is no simple single "doomsday argument" for ADT. There are many different scenarios (where you need to specify the situation, the probabilities, the altruisms of the agents, and the decisions they are facing), and in some of them, something that resembles the classical doomsday argument pops up, and in others it doesn't.