 Church argues as follows: Let \(O1,\) \(O2,\) and \(O3\) be independent observation sentences (no one of them entails any other), and suppose \(S\) is any sentence whatsoever—it might be “The Nothing Nots”. Church shows that Ayer’s definition entails that either \(S\) or its negation “It is not the case that the Nothing Nots”, is meaningful. For consider the disjunctive sentence