Second, what decision theory does best, if run by an agent, depends crucially on what the world is like. To see this, let’s go back to question that Y&S ask of what decision theory I’d want my child to have. This depends on a whole bunch of empirical facts: if she might have a gene that causes cancer, I’d hope that she adopts EDT; though if, for some reason, I knew whether or not she did have that gene and she didn’t, I’d hope that she adopts CDT. Similarly, if there were long-dead predictors who can no longer influence the way the world is today, then, if I didn’t know what was in the opaque boxes, I’d hope that she adopts EDT (or FDT); if I did know what was in the opaque boxes (and she didn’t) I’d hope that she adopts CDT. Or, if I’m in a world where FDT-ers are burned at the stake, I’d hope that she adopts anything other than FDT.
I think there’s a lot wrong here, but I’m particularly surprised by Will’s claim that he’d want his daughter to follow EDT in the world where a gene might cause cancer. Once she’s born and has the gene (or doesn’t), the decision theory she follows after that point makes absolutely no difference. I assume he’s thinking about the smoking lesions problem here. In such a world, I might hope my daughter doesn’t have the desire to smoke, but I wouldn’t hope she follows EDT! What difference would that possibly make?
I likewise would want my child to follow FDT in both the opaque and transparent Newcomb’s problem, so I wouldn’t want her to follow CDT in the case where I know the box contents and she doesn’t. And the burning-at-the-stake world is just silly and unfair.
I think there’s a lot wrong here, but I’m particularly surprised by Will’s claim that he’d want his daughter to follow EDT in the world where a gene might cause cancer. Once she’s born and has the gene (or doesn’t), the decision theory she follows after that point makes absolutely no difference. I assume he’s thinking about the smoking lesions problem here. In such a world, I might hope my daughter doesn’t have the desire to smoke, but I wouldn’t hope she follows EDT! What difference would that possibly make?
I likewise would want my child to follow FDT in both the opaque and transparent Newcomb’s problem, so I wouldn’t want her to follow CDT in the case where I know the box contents and she doesn’t. And the burning-at-the-stake world is just silly and unfair.