William Heytesbury and the Treatment of Insolubilia in Fourteenth-Century England Followed by a Critical Edition of Three Anonymous Treatises De Insolubilibus Inspired by Heytesbury

When one considers the history of the Liar paradox’s treatment in medieval logic, it is evident that the solution offered by William Heytesbury (before 1313–ca. 1373) was not only very original, although he himself denies it was, but also very influential. Indeed, it was more or less taken up again by John of Holland (second half of fourteenth century), Robert Fland (between 1335 and 1370), the author of a treatise preserved in Ms. Vat. Lat. 674 (ca. 1368), John Hunter(?) (1390 at the latest), the “Pseudo-Heytesbury” (after 1335) and the author of a treatise preserved in Ms. Oxford, Lat. Misc. e.79 (after 1335). The three first texts mentioned have already been edited;1 I here offer a critical edition of the last three. But before studying those texts, I should proceed to some recollections and remarks about Heytesbury’s position on insolubles. These preliminary remarks will indeed allow us to understand, first, to what extent English logicians after Heytesbury followed him or not and, second, how they solved several questions the Mertonian master left aside, using for that, for the most part, the text of one other slightly earlier mertonian master, Thomas Bradwardine (1295–1349).2 Through this journey through the texts we will be able to recount the outlines of the development of the debate on insolubles in fourteenth-century England.