I have recently been reading an article by Stewart Cohen called "Knowledge and Context." In the article Cohen argues for the context-sensitivity of the justification of knowledge attributions. The article is very interesting, but I find myself disagreeing with its conclusions. Also, I think that not only does Cohen NOT reach his goal of avoiding skepticism (though he may have made steps in avoiding a radical form of skepticism), but I believe that he actually drives us to be skeptical.
In the article Cohen says that a person must have good reasons in order to know. He defines good reasons (ideally) as reasons that are undefeated by the evidence one possesses (575, The Journal of Philosophy, Vol. 8, No. 10, Oct. 1986). He then argues that the relevance of defeaters, for justification, is based upon the context that one is a part of. For instance, Cohen says, "The relevance of a defeater...can range from obvious to very subtle. Suppose in the case imagined that d defeats through a very subtle line of reasoning that would escape all but the most acute intelligence. S believes q only because he is of normal intelligence and so fails to appreciate the defeating effect of d. With the details specified, does S fail to have good reasons? Here we might hesitate, granting that one can have good reasons provided that one does not believe any obvious defeaters" (Cohen, 575). He then defines obvious subjectively, based upon the subject's (S) own reasoning ability, but also intersubjectively, based upon the reasoning ability of a broader social group of which S is a member. By setting the reasoning up in this way, Cohen allows for a few more distinctions. Something can be obvious subjectively but not obvious intersubjectively (for instance, a super genius sees obvious defeaters to some given reason that the rest of us cannot). In this instance defeater is subjectively obvious (or evident) but intersubjectively opaque. So Cohen defines intersubjectively opaque as possessing in a social knowledge, evidence that would defeat some reason for believing something, but then not having the ability or clarity of thought as a community for that defeater to be evident. In the same way, something can be intersubjectively obvious, but subjectively not obvious or opaque. In this case the community possesses some evident defeater for discounting some reason in their knowledge, but some subject in that community is not able to see the defeating "triumph" of the defeater on the reason. Such a one who lacks the ability to see the obviousness of an intersubjective defeater is said by Cohen to be subjectively opaque. More next time.