Sempiternal Truth. The Bolzano-Twardowski-Lesniewski Axis

In 1913 Stanisław Leśniewski published his article on the sempiternity of truth, ‘Is Truth only Eternal or is it both Eternal and Sempiternal?’ (1913). The paper, directed against Kotarbiński’s ‘The Problem of the Existence of the Future’ (1913), made an important contribution to the debate on the excluded middle current in the Lvov circle in those years. The discussion involved at the same time absoluteness, eternity and sempiternity of truth, i. e. truth for ever and truth since ever, and had as ideal reference point Twardowski’s ‘On the So-called Relative Truths’ (1900), where the founder of the Lvov-Warsaw School had attacked the relativity of truth. Contrasting Kotarbiński’s positions, Leśniewski defended ‘absolutism’, consequently taking sides with Twardowski. Twardowski had revived Bernard Bolzano’s ideas on the subject, and, mainly thanks to him, these became known in the Lvov-Warsaw School. There is no doubt that Leśniewski knew Twardowski’s ideas and it seems evident that the latter influenced him: Leśniewski’s results are mostly compatible with the ‘absolutistic’ content of Twardowski’s 1900 article. And, similarly, no doubts can be raised about the Bolzanian origin of the aspects of eternity and sempiternity of truth defended by Twardowski in Relative Truths: though his name is not quoted, traces of Bolzano’s legacy can be found even in the examples given by Twardowski, some of which are the same as used by Bolzano in his Wissenschaftslehre. Yet, since