Among logicians there exists the widely accepted view that classical logic as developed by Frege, Russell, Peano, Peirce and others is not able to master all the problems arising in connection with indirect speech and similar phenomena. There is a myth that classical or so-called extensional logic is good only for one part of our language, for extensional contexts, while a large area of our language, consisting of intensional or opaque contexts, needs a special, non-extensional or intensional logic. It is (...) obvious that this point of view denies the universality of logic and logical rules. (shrink)

The present work takes the decease of Horst Wessel as an opportunity to present and honour his work (and that of his group), which has not received the attention it deserves. The focus will be on works which might not be sufficiently well-known. Wessel was, as we aim to show, familiar with the international debate concerning logical and philosophical issues and strived to solve them by considering theories of logical consequence, a non-traditional theory of predication and the theory of logical (...) terms, all of which he developed in joint work with Alexander Sinowjew. Wessel had to significantly refine these theories in order to formulate his criticism towards alternative logics and to apply the theories to a treatment of intensional contexts. He was vehemently opposed to approaches which revised fundamental laws of classical logic. Questions concerning the history of Philosophy are addressed in Wessel’s criticism of the Kantian antinomies of pure reason, in Wessel’s contributions to the problem of universals and his analyses of fatalism, tychism and antifatalism. (shrink)