Michael Kremer defines fixed-point logics of truth based on Saul Kripke’s fixed point semantics for languages expressing their own truth concepts. Kremer axiomatizes the strong Kleene fixed-point logic of truth and the weak Kleene fixed-point logic of truth, but leaves the axiomatizability question open for the supervaluation fixed-point logic of truth and its variants. We show that the principal supervaluation fixed point logic of truth, when thought of as consequence relation, is highly complex: it is not even analytic. We also (...) consider variants, engendered by a stronger notion of ‘fixed point’, and by variant supervaluation schemes. A ‘logic’ is often thought of, not as a consequence relation, but as a set of sentences – the sentences true on each interpretation. We axiomatize the supervaluation fixed-point logics so conceived. (shrink)

Material kept in the National Library of Finland shows that from 1963 until 1969 Erik Stenius (1911–1990) worked on a book on antinomies , having been invited by the Dutch logician Evert Beth (1908–1964) to contribute a monograph to the North-Holland series Studies in Logic and the Foundations of Mathematics . The book was never published, but the manuscript has been found, and it is the purpose of this note to report on this finding.