I’m off to Northern Illinois tomorrow to give a talk (a department with an impressive group of epistemologists, if you haven’t noticed–clearly the pick of the crop for MA work in epistemology), but I’ve been thinking more about rules, principles, and rule-following. I’ll post some further thoughts here now, and will be back later in the weekend.
In his review in NDPR of Weirich’s latest book on decision rules for nonideal agents, Morton writes:
If there are rules for the decisions of nonideal agents then they will most likely run along the lines Weirich describes. So it is important to test his theory: if it fails then most likely there are no rules. Would that be a disaster? I think not: contrast rational decision with rational belief. Few philosophers believe that there are rules that tell us what to believe. There are principles that tell us how to evaluate the strength of evidence, and less definite principles that tell us how to gather evidence, and even less definite principles that tell us how to distinguish serious hypotheses from those not worth considering. All these are valuable and non-trivial, but they don’t add up to rules for belief.
Given recent discussion of rules and principles here and here, as well as the interesting discussion that followed, I found this quote quite pertinent. Morton doesn’t distinguish rules and principles, but that is not the central issue here, since I think he’s not thinking about epistemic principles in the Boghossian sense but rather rules that are not bearers of truth-value. The first idea is that there are no, or not enough, rules that have as consequent “believe p”. Such rules would correspond to epistemic obligation principles, and Morton is surely right that there are enough of these. There may be such principles if the antecedent contains everything a full and correct theory of justification involves, but even in that case one might wonder if belief is compelled rather than permitted. My own view is that it is compelled in such a case, but I won’t argue that here.
But I doubt the other claims, the claims that there are principles that “tell us how to evaluate strength of evidence,” and principles that “tell us how to gather evidence” and principles that tell us “how to distinguish serious hypotheses” from the rest. Remember that principles here are rules with imperatival consequents. Beyond rules encoding the implications of a complete theory of justification, there are no rules with consequents such as: “evaluate the strength of evidence for p within range R” or “behave in the following way when inquiring concerning p” or “adopt the view that H is a serious hypothesis.” The problem is that all such rules will correspond to principles of obligation, and a well-constructed intellectual life has all the openness ordinarily noted about the good life in general, and as a result, is subject to very few specific obligations. As noted already, I like the view that the full theory of justification will generate obligation principles when the entire theory is encoded in the antecedent of the principle, but short of that, they strike me as very hard to find.
I’ve ignored so far the qualifier “less definite” in Morton’s discussion of the principles. I’m not sure quite how to interpret the qualifier, however. Maybe the idea is to contrast generic advice (“buy low, sell high”) with specific advice (“buy IBM and sell Cisco today”). I’m really not sure here. Maybe if I understood the qualifier better, I’d grant that there are correct principles of this sort.