Perceptual dogmatism is the view that a perceptual seeming that P prima facie justifies P. Classical Bayesianism (CB), as I am using the term, is the idea that justification is accurately modelled by classical probability theory, which includes Bayes’ Theorem. A popular way of objecting to dogmatism goes something like this: dogmatism is incompatible with CB, so dogmatism is false. I’ll assume that you have some familiarity with this sort of objection, which can be found in White’s “Problems for Dogmatism”, Schiffer’s “Skepticism and the Vagaries of Justified Belief” (pgs 175-6), and Wright’s “The Perils of Dogmatism” (pg 42).
Suppose we grant the premise that dogmatism is incompatible with CB. Why in the world should we conclude that the CB wins? Why shouldn’t we reject CB instead? The latter view does have a number of virtues, but it is not as though dogmatism has nothing going for it. And CB has a number of well-known problems. So I repeat: if dogmatism and CB are incompatible, why should the Classical Bayesian win?
Here is a way of approaching the question: if the incompatibility between CB and dogmatism depends on the most controversial features of Classical Bayesianism, then dogmatism should win. For example, I find it implausible that a rational human being should assign a credence to every proposition or a credence of 1 to every necessary truth. I take it that these implausible claims are entailed by CB. To whatever extent the incompatibility arises because of CB’s commitment to either of those two claims, dogmatism should win and we should rework CB. If, however, the incompatibility relies only on the least controversial features of CB, then CB should win. Perhaps an example of something uncontroversial would be: if S assigns a credence to both P and P or Q, S is irrational for assigning P or Q a lower credence than P.
My suspicion is that you can only derive the incompatibility by relying on the most controversial features of dogmatism, such as the claim that I suffer a rational failing if I don’t assign every proposition a credence. Suppose I might reasonably fail to assign a credence to the proposition (~D) that I’m not being deceived into thinking there is a hand. That is, suppose that, prior to having an experience as of my hand, ~D has no probability for me (perhaps because I have no information one way or the other, I’ve never considered ~D, etc.). Now what’s the problem with the dogmatism allowing this: my experience provides me with justification to believe that I have a hand, and then, from my justified belief that I have a hand, I justifiably deduce ~D?
I admit that I’m worse than an idiot when it comes to formal epistemology, so this post is intended as a request for information as much as it is intended as a defense of dogmatism. And let me also stress that I’m not against formal epistemology. If dogmatism wins, then we shouldn’t give up on formal epistemology; rather, we should improve our formal modelling techniques.
(Btw: Peter Kung’s “On Having No Reason: Dogmatism and Bayesian Confirmation” provides a defense of dogmatism that may be a more intelligent way of pushing some of the points I make in this post. But perhaps Peter wouldn’t like to be associated with ideas that may be worse than idiotic.)