Accurate Enough, Comprehensive Enough, and Reasonable Enough Belief

Abstract

Peter Klein’s defeasibility theory has considerable appeal, but it cannot deal with cases in which someone’s beliefs are as accurate as humanly possible but don’t satisfy all the requirements of epistemic justification. Since this person would seem to know things that the rest of us don’t, it’s best to abandon the notion that knowledge requires justification, and to instead think about it in terms of sufficient information, where sufficient information is understood negatively. Whenever an individual has a true belief but seems not to have knowledge, there is some important aspect of the situation about which she lacks true beliefs.

This view is conspicuously similar to a defeasibility view. When someone intuitively lacks knowledge despite having a true belief, both views recommend looking for a truth about the situation that the person lacks. They differ only on whether to link the missing truth to a justification requirement. The gap between the two can be further narrowed by noting that justification comes in degrees. One is then in a position to argue that one can have knowledge only if one’s overall belief system meets at least minimal standards of reasonability. Since any belief system that is maximally accurate and comprehensive will meet such standards, the result is an approach to understanding knowledge that retains much of the spirit of the defeasibility theory while avoiding problems that arise from importing an overly strong standard of justification into the conditions of knowledge.