Thanks for the link to Wallace’s work. I think that he also fails in the same trap, that is he fails to distinguish “large” and “small” forms of self-undermining arguments.
The large one is a choice between two alternatives: “1) I am real; 2) I am BB, and therefore can’t have reasonable thoughts.”
The small argument is only (2) from above: “I am BB, and therefore I can’t have coherent thoughts. “Only the small argument is self-undermining but the large one stands because there is no probability update in (1) horn.
For example, I have a 10 per cent chance to believe that I am real a priory, based on theoretical physics. I know that BBs can’t update properly but it is not evidence on which I should update, as it is not news for me.
Another example: I can be either awake or dreaming. During dreaming I can’t effectively decide, am I awake or dreaming and properly calculate the chances of being in a dream. Sometimes I have lucid dreams and sometimes I have very realistic dreams. If we follow Carroll’s logic, we should conclude that dreaming is impossible, because it is cognitively unstable, and it could be that I am dreaming now about commenting in LW. But in real life, we assume that dreaming takes, say, 0.3 time of my subjective experiences and we ignore any probability computations about dreaming that we do during dreaming.
Thanks for the link to Wallace’s work. I think that he also fails in the same trap, that is he fails to distinguish “large” and “small” forms of self-undermining arguments.
The large one is a choice between two alternatives: “1) I am real; 2) I am BB, and therefore can’t have reasonable thoughts.”
The small argument is only (2) from above: “I am BB, and therefore I can’t have coherent thoughts. “Only the small argument is self-undermining but the large one stands because there is no probability update in (1) horn.
For example, I have a 10 per cent chance to believe that I am real a priory, based on theoretical physics. I know that BBs can’t update properly but it is not evidence on which I should update, as it is not news for me.
Another example: I can be either awake or dreaming. During dreaming I can’t effectively decide, am I awake or dreaming and properly calculate the chances of being in a dream. Sometimes I have lucid dreams and sometimes I have very realistic dreams. If we follow Carroll’s logic, we should conclude that dreaming is impossible, because it is cognitively unstable, and it could be that I am dreaming now about commenting in LW. But in real life, we assume that dreaming takes, say, 0.3 time of my subjective experiences and we ignore any probability computations about dreaming that we do during dreaming.