A Cognitive Cul-de-Sac

Abstract

Principle (A) is a cousin of the one used by Edmund Gettier to construct his well-known counterexamples. It has received its share of abuse, but no one seems prepared to abandon it.I Indeed, its poorer (I would say bankrupt) relatives (e.g., S knows everything implied by what he knowswhether or not he knows it is implied) have sometimes been taken as axiomatic in systems of epistemic logic. The second principle, though less precise, and more difficult to state in any crisp way, is taken for granted by all of us who believe that knowledge is transmissible. It is hard to see how something like this principle could fail to be true if communication is possible and education occurs. For the way we know much of what we know is by hearing it from others who know. The following example convinces me that both principles are false.2 This is not to say that they do not hold in special circumstances, only that to regain their status as principles their scope must be restricted. George loves Bordeaux wines and he is especially fond of those from the Medoc region of Bordeaux. He has quite a remarkable palate and unerringly identifies a genuine Medoc as a Bordeaux, and specifically as a Medoc, when he tastes one. Strangely enough, though, given his general knowledgeability about wines, George is confused about Chianti. He has