Abstract

In his paper ‘The logic of temporal discourse’, Pavel Tichý pointed out that contemporary systems of logic were unable to sufficiently formalise tenses. He therefore suggested temporal specification in transparent intensional logic (TIL), a system of logic that he developed. Discussing contemporary systems of logic, Tichý also took into account the system of Arthur N. Prior, who developed the first systems of modern temporal logic, and his criticism was also addressed to Prior. Tichý only focused, however, on Prior’s early systems of temporal logic. Patrick Blackburn recently raised the awareness that Prior also developed systems of hybrid logic in his latest periods. From the point of view of temporal specification, this system is particularly interesting as the system has greater expressive power than Prior’s early systems of temporal logic. It could also consequently deal with the problematic specifications of tenses that Pavel Tichý pointed out. It is not only the formal criterion that make Tichý and Prior’s approach suitable for comparison. Both logicians shared similar views on time and logic. All these convictions also influenced their systems of logic. The aim of this paper is to demonstrate that the temporal propositions that Tichý introduced as problematic could be formalised in Prior’s hybrid temporal logic. I will also compare formalisations in TIL and hybrid logic and Tichý and Prior’s views that influenced their systems of logic.