No abstract

Cook regards Sorenson's so-called 'the no-no paradox' as only a kind of 'meta-paradox' or 'quasi-paradox' because the symmetry principle that Sorenson imposes on the paradox is meta-theoretic. He rebuilds this paradox at the objectlanguage level by replacing the symmetry principle with some 'background principles governing the truth predicate'. He thus argues that the no-no paradox is a 'new type of paradox' in that its paradoxicality depends on these principles. This paper shows that any theory (not necessarily meeting Cook's background principles) is inconsistent with the T-schema instances for the no-no sentences, plus the T-schema instance for a Curry sentence associated with the symmetry of the no-no sentences. It turns out that the no-no paradox still depends on the problematic instances of the T-schema in a way that the liar paradox does. What distinguishes the no-no paradox is the T-schema instance for the above Curry sentence, which encodes Sorensen's symmetry principle at the object-language level.

A relativized version of Tarski's T-scheme is introduced as a new principle of the truth predicate. Under the relativized T-scheme, the paradoxical objects, such as the Liar sentence and Jourdain's card sequence, are found to have certain relative contradictoriness. That is, they are contradictory only in some frames in the sense that any valuation admissible for them in these frames will lead to a contradiction. It is proved that for any positive integer n, the n-jump liar sentence is contradictory in and only in those frames containing at least an n-jump odd cycle. In particular, the Liar sentence is contradictory in and only in those frames containing at least an odd cycle. The Liar sentence is also proved to be less contradictory than Jourdain's card sequence: the latter must be contradictory in those frames where the former is so, but not vice versa. Generally, the relative contradictoriness is the common characteristic of the paradoxical objects, but different paradoxical objects may have different relative contradictoriness.

No abstract