 Smith distinguishes between two ways in which a belief can come to possess this property of being reliable. One possibility is that a belief that p possesses it in virtue of the modal relationship with its basis e. In this case, e is a contributing reliable basis. Another possibility is when it is the content of the belief that p, rather than the belief’s modal relationship with its basis e, that guarantees by itself the belief’s reliability. In this case, e is a non-contributing reliable basis. An example of the first kind is s’s belief that P3, which is reliable because of its modal relationship with E3. There are obviously many sufficiently normal worlds in which P3 is false, but no sufficiently normal world in which P3 is false and E3 true. An example of the second kind is s’s belief that Q3 as based on E3. It is this belief’s content, and not its modal relationship with E3, that guarantees its reliability. As Smith puts it, there are no sufficiently normal worlds in which E3 is true and Q3 is false, but this is simply because there are no sufficiently normal worlds in which Q3 is false.