ABSTRACT

A vague concept is one with borderline cases. For instance, take the concept of baldness. To have literally no hair on one's head is to be bald. But then it is not surprising that, beyond agreeing that having no hair at all makes one bald, different people use “bald” differently. Maybe the concept of knowledge is like the concept of baldness. This chapter provides possible examples of vague concepts. It shows that since 1 percent reliability does not give students knowledge, 1.001 percent is similarly ineffective. After all, the 0.001 percent difference between 1 percent and 1.001 percent is trivial. A belief gained via eyes that are 1.001 percent reliable is insignificantly more reliable than one gained via eyes that are 1 percent reliable. Maybe a belief formed by a method that is 50 percent reliable is a clear borderline case.