Now suppose a case like the Smoking Lesion were to come up in real life. Someone like Eliezer could say [...]
In other words, for some highly atypical people who have given a lot of explicit thought to situations like the Smoking Lesion one (and who, furthermore, strongly reject EDT), deciding to smoke wouldn’t be evidence of having the lesion and therefore the SL situation for them doesn’t work as a counterexample to EDT. I think I agree, but I don’t see why it matters.
there might be a statistical association between choosing to smoke and having the lesion, but it still will not increase a person’s credence that he has the lesion, if the association goes away after controlling for some factor besides the choice, such as desire for smoking.
Yes, I agree. Just to be clear, it seems like you’re arguing here for “EDT doesn’t necessarily say not to smoke” but elsewhere for “TDT probably says not to smoke”. Is that right? I find the first of these distinctly more plausible than the second, for what it’s worth.
So if the Smoking Lesion is supposed to be a fair counterexample to CDT, we should do the same thing [sc. posit a very-near-100% correlation].
I’m not sure I follow the logic. Even a well-sub-100% Smoking Lesion situation is (allegedly) a counterexample to EDT, and it’s not necessary to push the correlation up to almost 100% for it to serve this purpose; the reason why you need a correlation near to 100% for Newcomb is that what makes it plausible (to the chooser in the Newcomb situation) that Omega really can predict his choices is exactly the fact that the correlation is so strong. If it were much weaker, the chooser would be entirely within his rights to say “My prior against Omega having any substantial predictive ability is extremely strong; no one has shown me the sort of evidence that would change my mind about that; so I don’t think my choosing to two-box is strong evidence that Omega will leave the second box empty; so I shall take both boxes.”
It’s not clear to me that anything parallel is true about the Smoking Lesion scenario, so I don’t see why we “should” push the correlations to practically-100% in that case.
(But I don’t think what you’re saying particularly depends on the correlation being practically 100%.)
I’m not sure what TDT, or Eliezer, would say about your refined smoking-lesion situation. I will think a bit more about what I would say about it :-).
“For some highly atypical people...” The problem is that anyone who discusses this situation is a highly atypical person. And such people cannot imagine actually having a higher credence that they have the lesion, if they choose to smoke. This is why people advocate the smoking answer; and according to what I said in my other comment, it is not a “real Smoking Lesion problem” as long as they think that way, or at least they are not thinking of it as one (it could be that they are mistaken, and that they should have a higher credence, but don’t.)
Just to be clear, it seems like you’re arguing here for “EDT doesn’t necessarily say not to smoke” but elsewhere for “TDT probably says not to smoke”. Is that right? I find the first of these distinctly more plausible than the second, for what it’s worth.
What I meant was: in the situations people usually think about, or at least the way they are thinking about them, EDT doesn’t necessarily say not to smoke. But these are not the situations that are equivalent to the real Newcomb problem—these are equivalent to the fake Newcomb situations. EDT does say not to smoke in the situations which are actually equivalent to Newcomb. When I said “TDT probably says not to smoke,” I was referring to the actually equivalent situations. (Although as I said, I am less confident about TDT now; it may simply be incoherent or arbitrary.)
You don’t need to have a 100% correlation either for Newcomb or for the Smoking Lesion. But you are right that the reason for a near 100% correlation for Newcomb is to make the situation convincing to the chooser. But this is just to get him to admit that the million will actually be more likely to be there if he takes only one box. In the same way, theoretically you do not need it for the Smoking Lesion. But again, you have to convince the chooser that he personally will have a higher chance of having the lesion if he chooses to smoke, and it is hard to convince people of that. As someone remarked about people’s attitude on one of the threads about this, “So the correlation goes down from 100% to 99.9% and suddenly you consider yourself one of the 0.1%?” If anything, it seems harder to convince people they are in the true Smoking Lesion situation, than in the true Newcomb situation. People find Newcomb pretty plausible even if the correlation is 90%, if it is both for one-boxers and two-boxers, but a 90% correlation in the lesion case would leave a lot of person’s opinions about whether they have the lesion unchanged, no matter whether they choose to smoke or not.
(But I don’t think what you’re saying particularly depends on the correlation being practically 100%.)
In other words, for some highly atypical people who have given a lot of explicit thought to situations like the Smoking Lesion one (and who, furthermore, strongly reject EDT), deciding to smoke wouldn’t be evidence of having the lesion and therefore the SL situation for them doesn’t work as a counterexample to EDT. I think I agree, but I don’t see why it matters.
Yes, I agree. Just to be clear, it seems like you’re arguing here for “EDT doesn’t necessarily say not to smoke” but elsewhere for “TDT probably says not to smoke”. Is that right? I find the first of these distinctly more plausible than the second, for what it’s worth.
I’m not sure I follow the logic. Even a well-sub-100% Smoking Lesion situation is (allegedly) a counterexample to EDT, and it’s not necessary to push the correlation up to almost 100% for it to serve this purpose; the reason why you need a correlation near to 100% for Newcomb is that what makes it plausible (to the chooser in the Newcomb situation) that Omega really can predict his choices is exactly the fact that the correlation is so strong. If it were much weaker, the chooser would be entirely within his rights to say “My prior against Omega having any substantial predictive ability is extremely strong; no one has shown me the sort of evidence that would change my mind about that; so I don’t think my choosing to two-box is strong evidence that Omega will leave the second box empty; so I shall take both boxes.”
It’s not clear to me that anything parallel is true about the Smoking Lesion scenario, so I don’t see why we “should” push the correlations to practically-100% in that case.
(But I don’t think what you’re saying particularly depends on the correlation being practically 100%.)
I’m not sure what TDT, or Eliezer, would say about your refined smoking-lesion situation. I will think a bit more about what I would say about it :-).
“For some highly atypical people...” The problem is that anyone who discusses this situation is a highly atypical person. And such people cannot imagine actually having a higher credence that they have the lesion, if they choose to smoke. This is why people advocate the smoking answer; and according to what I said in my other comment, it is not a “real Smoking Lesion problem” as long as they think that way, or at least they are not thinking of it as one (it could be that they are mistaken, and that they should have a higher credence, but don’t.)
What I meant was: in the situations people usually think about, or at least the way they are thinking about them, EDT doesn’t necessarily say not to smoke. But these are not the situations that are equivalent to the real Newcomb problem—these are equivalent to the fake Newcomb situations. EDT does say not to smoke in the situations which are actually equivalent to Newcomb. When I said “TDT probably says not to smoke,” I was referring to the actually equivalent situations. (Although as I said, I am less confident about TDT now; it may simply be incoherent or arbitrary.)
You don’t need to have a 100% correlation either for Newcomb or for the Smoking Lesion. But you are right that the reason for a near 100% correlation for Newcomb is to make the situation convincing to the chooser. But this is just to get him to admit that the million will actually be more likely to be there if he takes only one box. In the same way, theoretically you do not need it for the Smoking Lesion. But again, you have to convince the chooser that he personally will have a higher chance of having the lesion if he chooses to smoke, and it is hard to convince people of that. As someone remarked about people’s attitude on one of the threads about this, “So the correlation goes down from 100% to 99.9% and suddenly you consider yourself one of the 0.1%?” If anything, it seems harder to convince people they are in the true Smoking Lesion situation, than in the true Newcomb situation. People find Newcomb pretty plausible even if the correlation is 90%, if it is both for one-boxers and two-boxers, but a 90% correlation in the lesion case would leave a lot of person’s opinions about whether they have the lesion unchanged, no matter whether they choose to smoke or not.
This is correct.