Denis Bonnay: Nice Sentences will be Grounded

In this talk, I will discuss the notion of a grounded sentence in the theory of truth. Groundedness aims at capturing the idea of semantically well-behaved sentences, whose truth-values depend, directly or indirectly, on wordly, that is non alethic, facts. In standard Kripkean approaches, groundedness is a mere by-product of the fixed-point definition of the extension of the truth predicate. Recently, Leitgeb has proposed to turn the tables and first define what grounded sentences are, so that the theory of truth can then rely on that characterization. However, the resulting set of sentences is different from what we usually get and exhibits some seemingly strange patterns. This raises a question of conceptual priority: is it sound to define groundedness without first defining truth? I will suggest a positive answer to the question by showing that Leitgeb’s approach can be recast in terms of groundedness jumps, and by proposing a systematic study of what groundedness jumps can and cannot do, as compared to alethic jumps.