Editing Liar paradox (section)

===Jon Barwise and John Etchemendy===
[[Jon Barwise]] and [[John Etchemendy]] propose that the liar sentence (which they interpret as synonymous with the Strengthened Liar) is ambiguous. They base this conclusion on a distinction they make between a "denial" and a "negation". If the liar means, "It is not the case that this statement is true", then it is denying itself. If it means, "This statement is not true", then it is negating itself. They go on to argue, based on [[situation semantics]], that the "denial liar" can be true without contradiction while the "negation liar" can be false without contradiction. Their 1987 book makes heavy use of [[non-well-founded set theory]].<ref name="Barwise1989"/>