dogmatism is the most promising way to justify the obvious fact that it is not irrational to refuse to hand over your wallet to a Pascal mugger. (If anyone disagrees that this is an obvious fact, please get in touch, and be prepared to hand over lots of cash).
There is another way out. We can agree that it is rational to hand over the wallet and thank heavens that we’re lucky not to be rational. I’m convinced by things like Kavka’s poison paradox and Newcomb’s paradox that sometimes it sucks to be rational. Maybe Pascal’s mugger is one of those cases.
Occam’s razor seems to be necessary in order to learn anything at all about the world from experience, but it remains an assumption.
There are plenty of other assumptions that would allow learning. For any specific complex way the world might be, x, we are able to learn given an assumption of bias toward simplicity for every hypothesis except for x and a bias for x. If all you have to justify Occam’s razor is overall usability, you’ve got very little reason to prefer it to nearby aberrations.
First, I think there is an important difference between Pascal’s mugger, and Kavka’s poison/Newcomb’s paradox. The latter two are examples of ways in which a theory of rationality might be indirectlyself-defeating. That means: if we try to achive the aims given to us by the theory, they can sometimes be worse achieved than if we had followed a different theory instead. This means there is a sense in which the theory is failing on its own terms. It’s troubling when theories of rationality or ethics have this property, but actually any theory will have this property in some concievable circumstances, because of Parfit’s satan thought experiment (if you’re not familiar, do a ctrl+F for satan here: https://www.stafforini.com/docs/Parfit%20-%20Reasons%20and%20persons.pdf doesn’t seem to have a specific wikipedia article that i can find).
Pascal’s mugger seems like a different category of problem. The naive expected utility maximizing course of action (without dogmatism) seems absurd, but not because it is self-defeating. The theory is actually doing well on its own terms. It is just that those terms seem absurd. I think the Pascal mugger scenario should therefore present more of a problem for the expected utility theory, than the Kavka’s poison/Newcomb’s paradox thought experiments do.
On your second point, I don’t have a good reply. I know there’s probably gaping holes in the defence of Occam’s razor I gave in the post, and that’s a good example of why.
I’m very interested though, do you know a better justification for Occam’s razor than usability?
The theory is actually doing well on its own terms.
Can you expand on what you mean by this? I would think that expected utility maximization is doing well insofar as your utility is high. If you take a lot of risky bets, you’re doing well if a few pay off. If you always pay the mugger, you probably think your decision theory is screwing you unless you find yourself in one of those rare situation where the mugger’s promises are real.
I’m very interested though, do you know a better justification for Occam’s razor than usability?
I don’t . I’m more or less in the same boat that I wish there was a better justification, and I’m inclined to continue using it because I have to (because there is no clear alternative, because it is human nature, etc.)
Lets assume for the moment that the probabilities involved are known with certainty. If I understand your original ‘way out’ correctly, then it would apply just as well in this case. You would embrace being irrational and still refuse to give the mugger your wallet. But I think here, the recommendations of expected utility theory in a Pascal’s mugger situation are doing well ‘on their own terms’. This is because expected utility theory doesn’t tell you to maximize the probability of increasing your utility, it tells you to maximize your utility in expectation, and that’s exactly what handing over your wallet to the mugger does. And if enough people repeated it enough times, some of them would eventually find themselves in a rare situation where the mugger’s promises were real.
In reality, the probabilities involved are not known. That’s an added complication which gives you a different way out of having to hand over your wallet, and that’s the way out I’m advocating we take in this post.
There is another way out. We can agree that it is rational to hand over the wallet and thank heavens that we’re lucky not to be rational. I’m convinced by things like Kavka’s poison paradox and Newcomb’s paradox that sometimes it sucks to be rational. Maybe Pascal’s mugger is one of those cases.
There are plenty of other assumptions that would allow learning. For any specific complex way the world might be, x, we are able to learn given an assumption of bias toward simplicity for every hypothesis except for x and a bias for x. If all you have to justify Occam’s razor is overall usability, you’ve got very little reason to prefer it to nearby aberrations.
Thanks for your comment, these are good points!
First, I think there is an important difference between Pascal’s mugger, and Kavka’s poison/Newcomb’s paradox. The latter two are examples of ways in which a theory of rationality might be indirectly self-defeating. That means: if we try to achive the aims given to us by the theory, they can sometimes be worse achieved than if we had followed a different theory instead. This means there is a sense in which the theory is failing on its own terms. It’s troubling when theories of rationality or ethics have this property, but actually any theory will have this property in some concievable circumstances, because of Parfit’s satan thought experiment (if you’re not familiar, do a ctrl+F for satan here: https://www.stafforini.com/docs/Parfit%20-%20Reasons%20and%20persons.pdf doesn’t seem to have a specific wikipedia article that i can find).
Pascal’s mugger seems like a different category of problem. The naive expected utility maximizing course of action (without dogmatism) seems absurd, but not because it is self-defeating. The theory is actually doing well on its own terms. It is just that those terms seem absurd. I think the Pascal mugger scenario should therefore present more of a problem for the expected utility theory, than the Kavka’s poison/Newcomb’s paradox thought experiments do.
On your second point, I don’t have a good reply. I know there’s probably gaping holes in the defence of Occam’s razor I gave in the post, and that’s a good example of why.
I’m very interested though, do you know a better justification for Occam’s razor than usability?
Can you expand on what you mean by this? I would think that expected utility maximization is doing well insofar as your utility is high. If you take a lot of risky bets, you’re doing well if a few pay off. If you always pay the mugger, you probably think your decision theory is screwing you unless you find yourself in one of those rare situation where the mugger’s promises are real.
I don’t . I’m more or less in the same boat that I wish there was a better justification, and I’m inclined to continue using it because I have to (because there is no clear alternative, because it is human nature, etc.)
Lets assume for the moment that the probabilities involved are known with certainty. If I understand your original ‘way out’ correctly, then it would apply just as well in this case. You would embrace being irrational and still refuse to give the mugger your wallet. But I think here, the recommendations of expected utility theory in a Pascal’s mugger situation are doing well ‘on their own terms’. This is because expected utility theory doesn’t tell you to maximize the probability of increasing your utility, it tells you to maximize your utility in expectation, and that’s exactly what handing over your wallet to the mugger does. And if enough people repeated it enough times, some of them would eventually find themselves in a rare situation where the mugger’s promises were real.
In reality, the probabilities involved are not known. That’s an added complication which gives you a different way out of having to hand over your wallet, and that’s the way out I’m advocating we take in this post.