 On the traditional justified true belief account of knowledge, a person cannot be said to know that a proposition \(p\) is true without having good reasons for believing that \(p\) is true. If Lucy knows that she will pass tomorrow’s exam, she must have good reasons for thinking that this is so. Consider now Lucy’s reasons. They will presumably consist of other beliefs she has, e.g., beliefs about how well she did earlier, about how well she has prepared, and so on. For Lucy to know that she will pass the exam, these other beliefs, upon which the first belief rests, must also be things that Lucy knows. Knowledge, after all, cannot be based on something less than knowledge, i.e., on ignorance (cf. Rescher 1979, 76). Since the reasons are themselves things that Lucy knows, those reasons must in turn be based on reasons, and so on. Thus, any knowledge claim requires a never-ending chain, or “regress”, of reasons for reasons. This seems strange, or even impossible, because it involves reference to an infinite number of beliefs. But most of us think that knowledge is possible.