I don’t think P(my epistemology) is a practically useful concept.
This is surprising to me -- I've always thought that whatever our understanding of knowledge was should apply to itself. If it doesn't, how do you know that your epistemology is right? An epistemology is the thing that's meant to give you the answer to the question. So it seems like a problem if an epistemology can't apply to itself.
One response might be 'Bayesianism is about science, not philosophy', but then on what basis are you adopting bayesianism? if that decision is supported by some other epistemology, then why not use that instead? (it seems like it might be more powerful because it can do something bayesianism can't)
Does critical fallibilism have anything to say about itself? If it gives itself a full bill of health, that’s no more useful than the statement “This sentence is true”, which can consistently be assigned any truth value.
Yeah it does, though a 'full bill of health' might mean something different. CF says that we should use the best ideas we have access to. "Best" means that it works to achieve a goal and is unrefuted (no unanswered decisive criticisms). CF claims it has no decisive criticisms (at least insofar as the epistemology is concerned), but does not claim such criticisms are impossible (it's fallibilist after all). CF is Elliot Temple's school and he is very willing to debate (which means a forum discussion).
From Debate Policies Introduction, he says:
Debate is important because it enables errors to be corrected. If an intellectual is wrong, and a critic has an important correction, then refusing to debate is one of the common ways the intellectual can stay wrong.
One of goals of CF-ists is to find and debate people who disagree with you because that's the best way to get criticisms, which are an integral part of error correction and improvement.
But also the world isn't very good for debate, at least not at a high level. It's hard to find people and forums who will continue a discussion to it's conclusion. So maybe CF isn't as good as it could be if there was more debate.
If someone knew of a criticism of CF, then Elliot would want to know. If he disagreed, he'd want a public discussion about it.
I can expand on anything if you have questions.
Can Bayesianism deal with the mail-order prophet scam? If so, how?
This scam uses a segmented mailing list and a large initial population to advertise predictions so that a 'winning' portion of recipients receive an apparently improbable series of correct predictions. Most recipients (the 'losers') receive an incorrect prediction at some point.
For clarity, here is the situation:
A Bayesian with no prior knowledge of the scam receives a letter advertising stock predictions via a new proprietary quantitative model. The letter predicts that by the end of the month, stock XYZ will be up. It also states that the firm will prove their legitimacy by sending 6 more predictions (one per month) that will correctly predict whether XYZ is up or down. Sure enough, the Bayesian receives each letter, and the predictions all end up correct!
Unbeknownst to the Bayesian, 63 other Bayesians also received the first letter, 31 others received the second, 15 the third, 7 the fourth, 3 the fifth, and 1 other received the sixth letter. Our unlucky Bayesian was the only one to receive the seventh.
The question is, assuming no knowledge of the scam or communication with the "losers" (for whom a stock prediction was wrong), should the Bayesian -- strictly adhering to Bayesian Epistemology -- believe that the firm's stock predictions are legit?
I don't know how to approach this from a Bayesian perspective and would appreciate any guidance from someone who's more familiar. My intuition is that the Bayesian should believe that the predictions are legit (which we observers know to be incorrect).
Also I feel I should disclose that I'm not a Bayesian (rather a Critical Fallibilist), and I'm looking for the best Bayesian answers to this problem (links to prior material welcome). It's often quite hard to find the best answers to a problem from a particular school, so please bear with me if I've missed something obvious.