We grant that it is possible to punish agents for using a specific decision proce-
dure, or to design one decision problem that punishes an agent for rational behavior
in a different decision problem. In those cases, no decision theory is safe. CDT per-
forms worse that FDT in the decision problem where agents are punished for using
CDT, but that hardly tells us which theory is better for making decisions. [...]
Yet FDT does appear to be superior to CDT and EDT in all dilemmas where the
agent’s beliefs are accurate and the outcome depends only on the agent’s behavior
in the dilemma at hand. Informally, we call these sorts of problems “fair problems.”
By this standard, Newcomb’s problem is fair; Newcomb’s predictor punishes and
rewards agents only based on their actions. [...]
There is no perfect decision theory for all possible scenarios, but there may be a
general-purpose decision theory that matches or outperforms all rivals in fair dilem-
mas, if a satisfactory notion of “fairness” can be formalized
Yet FDT does appear to be superior to CDT and EDT in all dilemmas where the agent’s beliefs are accurate and the outcome depends only on the agent’s behavior in the dilemma at hand
This is not true in cases even where mind-reading agents do not exist.
Consider the desert dilemma again with Paul Ekman, except he is actually not capable of reading people’s mind. Also assume your goal here is to be selfish and gain as much utility for yourself as possible. You offer him $50 in exchange for him taking you out of the desert and to the nearest village, where you will be able to draw out the money and pay him. He can’t read your mind but judges that the expected value is positive given most people in this scenario would be telling the truth. CDT says that you should simply not pay him when you reach the village, but FDT has you $50 short. In this real world scenario, that doesn’t include magical mind-reading agents, CDT is about $50 up from FDT.
The only times FDT wins against CDT is in strange mind-reading thought experiments that won’t happen in the real world.
In your new dilemma, FDT does not say to pay the $50. It only says to pay when the driver’s decision of whether or not to take you to the city depends on what you are planning to do when you get to the city. Which isn’t true in your setup, since you assume the driver can’t read faces.
The agent in this scenario doesn’t necessarily know if the driver can read faces or not, in the original problem the agent isn’t aware of this information. Surely if FDT advises you pay him on arrival in the face reading scenario, you would do the same in the non-face reading scenario since the agent can’t tell them apart.
No, the whole premise of the face-reading scenario is that the agent can tell that his face is being read, and that’s why he pays the money. If the agent can’t tell whether his face is being read, then his correct action (under FDT) is to pay the money if and only if (probability of being read) times (utility of returning to civilization) is greater than (utility of the money). Now, if this condition holds but in fact the driver can’t read faces, then FDT does pay the $50, but this is just because it got unlucky, and we shouldn’t hold that against it.
Then you violate the accurate beliefs condition.
(If the world is infact a random mixture in proportion which their beliefs track correctly, then fdt will do better when averaging over the mixture)
True beliefs doesn’t mean omniscience. It is possible to have only true beliefs but still not know everything. In this case, the agent might not know if the driver can read minds but still have accurate beliefs otherwise.
The setup violates a fairness condition that has been talked about previously.
From https://arxiv.org/pdf/1710.05060.pdf, section 9:
This is not true in cases even where mind-reading agents do not exist.
Consider the desert dilemma again with Paul Ekman, except he is actually not capable of reading people’s mind. Also assume your goal here is to be selfish and gain as much utility for yourself as possible. You offer him $50 in exchange for him taking you out of the desert and to the nearest village, where you will be able to draw out the money and pay him. He can’t read your mind but judges that the expected value is positive given most people in this scenario would be telling the truth. CDT says that you should simply not pay him when you reach the village, but FDT has you $50 short. In this real world scenario, that doesn’t include magical mind-reading agents, CDT is about $50 up from FDT.
The only times FDT wins against CDT is in strange mind-reading thought experiments that won’t happen in the real world.
In your new dilemma, FDT does not say to pay the $50. It only says to pay when the driver’s decision of whether or not to take you to the city depends on what you are planning to do when you get to the city. Which isn’t true in your setup, since you assume the driver can’t read faces.
The agent in this scenario doesn’t necessarily know if the driver can read faces or not, in the original problem the agent isn’t aware of this information. Surely if FDT advises you pay him on arrival in the face reading scenario, you would do the same in the non-face reading scenario since the agent can’t tell them apart.
No, the whole premise of the face-reading scenario is that the agent can tell that his face is being read, and that’s why he pays the money. If the agent can’t tell whether his face is being read, then his correct action (under FDT) is to pay the money if and only if (probability of being read) times (utility of returning to civilization) is greater than (utility of the money). Now, if this condition holds but in fact the driver can’t read faces, then FDT does pay the $50, but this is just because it got unlucky, and we shouldn’t hold that against it.
Then you violate the accurate beliefs condition. (If the world is infact a random mixture in proportion which their beliefs track correctly, then fdt will do better when averaging over the mixture)
True beliefs doesn’t mean omniscience. It is possible to have only true beliefs but still not know everything. In this case, the agent might not know if the driver can read minds but still have accurate beliefs otherwise.