Comment by mitthrowaway2
1 hour ago
> if you believe it will rain with probability 0.7 but you are 80% sure of your belief
What does this even mean...?
If I believe it will rain with probability 0.7, that 0.7 figure should already be taking into account the sum total of all of my uncertainty over all of my beliefs: my trust in the weather forecast, my past experience with the local area in this season, my certainty that the earth will continue to exist tomorrow.
Bayesians of course accept that their models can have errors, and if they're doing a good job they'll factor all of the most influential ones into the probability calculation itself.
> What does this even mean...?
You are making the same point that I did, if you read the rest. 0.7 at 80% is an intermediate step in formulating a forecast, and the point is to show that you cannot stop there and have to include everything in your number, like you have said. In your words, the intermediate steps are what you list (trust in weather forecasts, past experience,…).
No, what I'm saying is that 0.7 is the ending point of the calculation, and there is no 80% associated with it. The 0.7 number already factors in my uncertainty in all of my knowledge about whether it will rain tomorrow. Saying that you're 80% sure of your 0.7 probability forecast throws a TypeErrorException.