Title: Combinatory Logic, Predicate Logic, Type Theory and The Foundation of Mathematics Abstract: Combinatory Logic(and lambda calculus) were first invented as very simple bases from which to develop logic, arithmetic and mathematics as a whole. Both Church's and Curry's systems, dating back to the 1930s, however, were proved inconsistent by Kleene and Rosser. Systems of illative combinatory logic (and lambda calculus) have since been developed that avoid the known paradoxes and still allow the development of logic, arithmetic, set theory etc. Only limited consistency has been proved. Modern type theory, which stems from early work of Church and Curry, has developed quite independently and has become much used in Computer Science. Surprisingly the valid statements of the form x_1:A_1,...,x_n:A_n |- M:B of very general type systems, can be translated into valid statements of illative combinatory logic of the form X_1,...,X_n |- Z. The reverse also holds for appropriate X_1,...,X_n. The seminar will introduce illative combinatory logic. It will show how this avoids the Curry paradox and indicate how it is used for the building up of logic, arithemetic and set theory. An idea of the relations between illative combinatory logics and type systems will also be given.