I think this comes down to the question of what subjective probabilities actually are. If something is concievable, do we have to give it a probability greater than 0? This post is basically asking, why should we?
The main reason I’m comfortable adapting my priors to be dogmatic is that I think there is probably not a purely epistemological ‘correct’ prior anyway (essentially because of the problem of induction), and the best we can do is pick priors that might help us to make practical decisions.
I’m not sure subjective probabilities can necessarily be given much meaning outside of the context of decision theory anyway. The best defence I know for the use of subjective probabilities to quantify uncertainty is due to Savage, and in that defence decisions are central. Subjective probabilities fundamentally describe decision making behaviour (P(A) > P(B) means someone will choose to receive a prize if A occurs, rather than if B occurs, if forced to choose between the two).
And when I say that some infinite utility scenario has probability 0, I am not saying it is inconcievable, but merely describing the approach I am going to take to making decisions about it: I’m not going to be manipulated by a Pascal’s wager type argument.
I think this comes down to the question of what subjective probabilities actually are. If something is concievable, do we have to give it a probability greater than 0? This post is basically asking, why should we?
The main reason I’m comfortable adapting my priors to be dogmatic is that I think there is probably not a purely epistemological ‘correct’ prior anyway (essentially because of the problem of induction), and the best we can do is pick priors that might help us to make practical decisions.
I’m not sure subjective probabilities can necessarily be given much meaning outside of the context of decision theory anyway. The best defence I know for the use of subjective probabilities to quantify uncertainty is due to Savage, and in that defence decisions are central. Subjective probabilities fundamentally describe decision making behaviour (P(A) > P(B) means someone will choose to receive a prize if A occurs, rather than if B occurs, if forced to choose between the two).
And when I say that some infinite utility scenario has probability 0, I am not saying it is inconcievable, but merely describing the approach I am going to take to making decisions about it: I’m not going to be manipulated by a Pascal’s wager type argument.
Make sense!