Wolfgang Lenzen

Abaelards Logik Wolfgang Lenzen

This book offers a comprehensive presentation of the logical theories of Abelard. By means of a theory of destructive vs. separating negation, the usual Square of Opposition is transformed into an Octagon. Furthermore, by means of the notion of relevant implication, Abelard tries to avoid the paradoxes of strict implication and thus to save the laws of connexive implication.