shminux comments on Can anyone explain to me why CDT two-boxes? - Less Wrong Discussion
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Here is my take on the whole thing, fwiw.
The issue is assigning probability to the outcome (Omega predicted player one-boxing whereas player two-boxed), as it is the only one where two-boxing wins. Obviously any decision theorists who assigns a non-zero probability to this outcome hasn't read the problem statement carefully enough, specifically the part that says that Omega is a perfect predictor.
EDT calculates the expected utility by adding, for all outcomes (probability of outcome given specific action)*payoff of the outcome. In the Newcomb case the contentious outcome has zero probability because "perfect predictor" means that a player never two-boxes unless Omega predicted so.
CDT does not calculate (probability of a certain outcome given specific action), but rather (probability that, if the action were performed, the outcome happens). In the Newcomb case this (probability of $1,001,000 payout were the player to two-box) can be (mis-)interpreted as certainty because "boxes already contain the prizes". This statement is in contradiction with the the "perfect predictor" clause.
In other words, the argument "Because your choice of one or two boxes can't causally affect the Predictor's guess, causal decision theory recommends the two-boxing strategy." is not really a CDT argument, but a misunderstanding of the problem statement. The suggested option ($M+$T) in SEP is actually never an option.