A paradox can be thought of as a set of mutually inconsistent claims in which each claim seems true. For example, consider the sentence, “I am now speaking falsely.” This statement, sometimes called the liar sentence (L), entails a group of claims that, although plausibly following from “I am now speaking falsely,” cannot all be true. If L is true, then, because the claim is that I am now speaking falsely, my claim (L) is false. And if L is false, then presumably I am not now speaking falsely, and hence, L is true. This set of mutually inconsistent claims is known at the liar paradox. It is one of the oldest paradoxes in the Western philosophical tradition and notoriously difficult to solve. There is ...