I've often had half-finished LW post ideas and crossed them off for a number of reasons, mostly they were too rough or undeveloped and I didn't feel expert enough. Other people might worry their post would be judged harshly, or feel overwhelmed, or worried about topicality, or they just want some community input before adding it.
So: this is a special sort of open thread. Please post your unfinished ideas and sketches for LW posts here as comments, if you would like constructive critique, assistance and checking from people with more expertise, etc. Just pile them in without worrying too much. Ideas can be as short as a single sentence or as long as a finished post. Both subject and presentation are on topic in replies. Bad ideas should be mined for whatever good can be found in them. Good ideas should be poked with challenges to make them stronger. No being nasty!
Let's empty out my draft folder then....
Counterfactual Mugging v. Subjective Probability
A couple weeks ago, Vladimir Nesov stirred up the biggest hornet's nest I've ever seen on LW by introducing us to the Counterfactual Mugging scenario.
If you didn't read it the first time, please do -- I don't plan to attempt to summarize. Further, if you don't think you would give Omega the $100 in that situation, I'm afraid this article will mean next to nothing to you.
So, those still reading, you would give Omega the $100. You would do so because if someone told you about the problem now, you could do the expected utility calculation 0.5U(-$100)+0.5U(+$10000)>0. Ah, but where did the 0.5s come from in your calculation? Well, Omega told you he flipped a fair coin. Until he did, there existed a 0.5 probability of either outcome. Thus, for you, hearing about the problem, there is a 0.5 probability of your encountering the problem as stated, and a 0.5 probability of your encountering the corresponding situation, in which Omega either hands you $10000 or doesn't, based on his prediction. This is all very fine and rational.
So, new problem. Let's leave money out of it, and assume Omega hands you 1000 utilons in one case, and asks for them in the other -- exactly equal utility. What if there is an urn, and it contains either a red or a blue marble, and Omega looks, maybe gives you the utility if the marble is red, and asks for it if the marble is blue? What if you have devoted considerable time to determining whether the marble is red or blue, and your subjective probability has fluctuated over the course of you life? What if, unbeknownst to you, a rationalist community has been tracking evidence of the marble's color (including your own probability estimates), and running a prediction market, and Omega now shows you a plot of the prices over the past few years?
In short, what information do you use to calculate the probability you plug into the EU calculation?
It's a little too strong, I think you shouldn't give away the $100, because you are just not reflectively consistent. It's not you who could've ran the expected utility calculation to determine that you should give it away. If you persist, by the time you must do the action it's not in your interest anymore, it's a lost cause. And that is a subject of another post that has been lying in draft form for some time.
If you are strong enough to be reflectively consistent, then ...
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