My thoughts:
1) The failure of CDT is its modeling of the decision process as ineffable ‘free will’ upon which things in the past cannot depend. Deviation from CDT is justified only when such dependencies exist.
2) The assumption that your decision is predictable requires the existence of such a dependency.
3) If we postulate that no such dependency exists, either CDT wins or our postulates are contradictory.
In particular, in Newcomb’s Soda, the assumptions that the soda flavor predicts the ice-cream flavor with high probability and that the assignment of soda (and the choice of subjects) is uncorrelated with subjects’ decision theory require that we are exceptional in employing decision theory. If lots of subjects were using CDT or EDT, they would all be choosing ice cream independently of their soda, and we wouldn’t see that correlation (except maybe by coincidence). So it doesn’t have to be stated in the problem that other subjects aren’t using evidential reasoning—it can be seen plainly from the axioms! To assume that they are reasoning as you are is to assume a contradiction.
The AB game is confusing because it flirts with contradiction. You act as if you’re free to choose A or B according to your decision theory while simultaneously assuming that Omega can predict your choice perfectly. But in fact, the only way Omega can predict perfectly is by somehow interacting with your decision theory. He can either administer the game only to people whose decision theory matches their genes, or manipulate people’s answers, or manipulate their genes. In the first case, EDTers will get a free gene test if they have G_A, but will not be miraculously healed if they have G_B. In the second case, you’ll find yourself pressing ‘B’ if you have G_B no matter what you try to precommit to. In the third case only, you have legitimate reason to commit to ‘A’, because your predetermined decision has causal influence on your genes.
You might try to counter with the case where Omega ensures that all children who are born will answer in a way consistent with their genes, and both things are determined at conception. But if this is the case, then if you have G_B, you can’t commit yourself to EDT no matter how hard you think about decision theory. This follows from the assumptions, and the only reason to think otherwise is if you still count free will among your premises.
If lots of subjects were using CDT or EDT, they would all be choosing ice cream independently of their soda, and we wouldn’t see that correlation (except maybe by coincidence). So it doesn’t have to be stated in the problem that other subjects aren’t using evidential reasoning—it can be seen plainly from the axioms! To assume that they are reasoning as you are is to assume a contradiction.
If lots of subjects were using CDT or EDT, they would be choosing ice cream independently of their soda iff the soda has no influence on whether they argue according to CDT or EDT. It is no logical contradiction to say that the sodas might affect which decision theoretic intuitions a subject is going to have. As long as we don’t specify what this subconscious desire for ice cream exactly means, it is thinkable that the sodas imperceptibly affect our decision algorithm. In such a case, most of the V-I people (the fraction originating from V-S) would be attracted to causal reasoning, whereas most of the Ch-I people (the fraction originating from Ch-S) would find the evidential approach compelling.
One can say now that the sodas “obviously” do not affect one’s decision theory, but this clearly had to be pointed out when introducing a “subconscious desire.” I agree that once it is specified that we are the only agents using decision theory, screening off applies. But the game is defined in a way that we are subjects of a study where all the subjects are rewarded with money:
It so happens that all participants in the study who test the Chocolate Soda are rewarded with a million dollars after the study is over, while participants in the study who test the Vanilla Soda receive nothing. But subjects who actually eat vanilla ice cream receive an additional thousand dollars, while subjects who actually eat chocolate ice cream receive no additional payment.
After reading this, it is not a priori clear to me that I would be the only subject who knows about the money at stake. To the contrary, as one of many subjects I assume that I know as much as other subjects know about the setting. Once other subjects know about the money they probably also think about whether choosing Ch-I or V-I produces the better outcome. It seems to me that all the agents base their decision on some sort of intuition about which would be the correct decisional algorithm.
To sum up, I tend to assume that other agents play a decision theoretic game as well and that the soda might affect their decision theoretic intuitions. Even if we assigned a low prior to the event that the sodas affect the subject’s decision algorithms, the derived reasoning would not be invalid but it’s power would shrink in proportion to the prior. Finally, it is definetly not a contradictory statement to say that the soda affects how the subject’s decide and that the subject’s use CDT or EDT.
By ‘using [CDT|EDT]‘, I meant ‘adhering to a belief in [CDT|EDT] that predates drinking the soda.’ If you’re the only one (or one of the only ones) doing this, screening off would apply, right? But if others are doing this, there would be fewer correct predictions. And if you aren’t doing this, you’ll switch to CDT if you get CS, making your reasoning today for naught.
(Doing decsion theory logically enough to overcome your subconscious desires would have the same effect as sticking to your pre-soda beliefs—either way you get an ice cream choice independent of your soda)
My thoughts: 1) The failure of CDT is its modeling of the decision process as ineffable ‘free will’ upon which things in the past cannot depend. Deviation from CDT is justified only when such dependencies exist. 2) The assumption that your decision is predictable requires the existence of such a dependency. 3) If we postulate that no such dependency exists, either CDT wins or our postulates are contradictory.
In particular, in Newcomb’s Soda, the assumptions that the soda flavor predicts the ice-cream flavor with high probability and that the assignment of soda (and the choice of subjects) is uncorrelated with subjects’ decision theory require that we are exceptional in employing decision theory. If lots of subjects were using CDT or EDT, they would all be choosing ice cream independently of their soda, and we wouldn’t see that correlation (except maybe by coincidence). So it doesn’t have to be stated in the problem that other subjects aren’t using evidential reasoning—it can be seen plainly from the axioms! To assume that they are reasoning as you are is to assume a contradiction.
The AB game is confusing because it flirts with contradiction. You act as if you’re free to choose A or B according to your decision theory while simultaneously assuming that Omega can predict your choice perfectly. But in fact, the only way Omega can predict perfectly is by somehow interacting with your decision theory. He can either administer the game only to people whose decision theory matches their genes, or manipulate people’s answers, or manipulate their genes. In the first case, EDTers will get a free gene test if they have G_A, but will not be miraculously healed if they have G_B. In the second case, you’ll find yourself pressing ‘B’ if you have G_B no matter what you try to precommit to. In the third case only, you have legitimate reason to commit to ‘A’, because your predetermined decision has causal influence on your genes.
You might try to counter with the case where Omega ensures that all children who are born will answer in a way consistent with their genes, and both things are determined at conception. But if this is the case, then if you have G_B, you can’t commit yourself to EDT no matter how hard you think about decision theory. This follows from the assumptions, and the only reason to think otherwise is if you still count free will among your premises.
If lots of subjects were using CDT or EDT, they would be choosing ice cream independently of their soda iff the soda has no influence on whether they argue according to CDT or EDT. It is no logical contradiction to say that the sodas might affect which decision theoretic intuitions a subject is going to have. As long as we don’t specify what this subconscious desire for ice cream exactly means, it is thinkable that the sodas imperceptibly affect our decision algorithm. In such a case, most of the V-I people (the fraction originating from V-S) would be attracted to causal reasoning, whereas most of the Ch-I people (the fraction originating from Ch-S) would find the evidential approach compelling. One can say now that the sodas “obviously” do not affect one’s decision theory, but this clearly had to be pointed out when introducing a “subconscious desire.”
I agree that once it is specified that we are the only agents using decision theory, screening off applies. But the game is defined in a way that we are subjects of a study where all the subjects are rewarded with money:
(an excerpt of the definition in Yudkowsky (2010))
After reading this, it is not a priori clear to me that I would be the only subject who knows about the money at stake. To the contrary, as one of many subjects I assume that I know as much as other subjects know about the setting. Once other subjects know about the money they probably also think about whether choosing Ch-I or V-I produces the better outcome. It seems to me that all the agents base their decision on some sort of intuition about which would be the correct decisional algorithm.
To sum up, I tend to assume that other agents play a decision theoretic game as well and that the soda might affect their decision theoretic intuitions. Even if we assigned a low prior to the event that the sodas affect the subject’s decision algorithms, the derived reasoning would not be invalid but it’s power would shrink in proportion to the prior. Finally, it is definetly not a contradictory statement to say that the soda affects how the subject’s decide and that the subject’s use CDT or EDT.
By ‘using [CDT|EDT]‘, I meant ‘adhering to a belief in [CDT|EDT] that predates drinking the soda.’ If you’re the only one (or one of the only ones) doing this, screening off would apply, right? But if others are doing this, there would be fewer correct predictions. And if you aren’t doing this, you’ll switch to CDT if you get CS, making your reasoning today for naught.
(Doing decsion theory logically enough to overcome your subconscious desires would have the same effect as sticking to your pre-soda beliefs—either way you get an ice cream choice independent of your soda)