The Smoking Lesion: A problem for evidential decision theory

This is part of a sequence titled "An introduction to decision theory". The previous post was Newcomb's Problem: A problem for Causal Decision Theories

For various reasons I've decided to finish this sequence on a seperate blog. This is principally because there were a large number of people who seemed to feel that this sequence either wasn't up to the Less Wrong standard or felt that it was simply covering ground that had already been covered on Less Wrong.

The decision to post it on another blog rather than simply discontinuing it came down to the fact that other people seemed to feel that the sequence had value. Those people can continue reading it at "The Smoking Lesion: A problem for evidential decision theory".

Alternatively, there is a sequence index available: Less Wrong and decision theory: sequence index

This is part of a sequence titled "An introduction to decision theory". The previous post was Newcomb's Problem: A problem for Causal Decision Theories

Alternatively, there is a sequence index available: Less Wrong and decision theory: sequence index

You can say the same thing about Newcomb's problem. It doesn't mean you can choose whether or not there will be a million in one of the boxes. It means that if there is a million in one of the boxes, then "some combination of logic, rationalisation or impulse will make you decide" to choose only one of the boxes (and if there's no million, then similarly you'll end up taking both boxes.) "You can then tell from your decision whether" you'll get the million or not, "but you couldn't have made the other decision, no matter what."

Either that, or you can be the first to outguess Omega and get the million as well as the thousand...

Nope, this reasoning doesn't work with Newcomb, and it doesn't work with the Smoking Lesion. If you want to win, you one-box, and you don't smoke.

It doesn't mean you can choose whether or not there will be a million in one of the boxes.

Yes I can, right now.

-2[anonymous]16y

I think the difference is that your disposition to one-box or two-box is something you can decide to change. Whether you were born with a lesion is not.

4RichardChappell16y

One potentially-significant difference: in Newcomb, it is precisely the fact that you're disposed to two-box that causes you to lose out. (Omega is detecting and responding to this very disposition.) In Smoking Lesion, the disposition to smoke is intrinsically harmless; it merely happens to be correlated (due to a common cause) with a disposition to get cancer. (But if you're right that the two cases are on a par, then that would significant increase my confidence that two-boxing is rational. The smoking lesion case is by far the more obvious of the two.)