the theory of types (pp. 218 — wherein he demonstrates how to create antinomies, including the definition of impredicable itself ("Is the definition of "impredicable" impredicable?"). He claims to show methods for eliminating the "paradoxes of syntax" ("logical paradoxes") — by use of the theory of types — and "the paradoxes of semantics" — by the use of metalanguage (his "theory of levels of language"). He attributes the suggestion of this notion to Russell and more concretely to Ramsey. Jean van Heijenoort 1967, third printing 1976, From Frege to Gödel: A Source Book in Mathematical Logic, 1879-1931, Harvard University Press, Cambridge MA, (pbk.) Mathematical logic Philosophy of mathematics Self-reference Concepts in logic Recursion