ABSTRACT
This chapter provides a general account of the intuitionistic approach to logic. Intuitionistic logic abandons some of the principles considered correct in classical logic. There is sufficient agreement among intuitionists as to which principles are correct, and which are incorrect, to enable the codification of intuitionistic logic as an axiom system. The definition of intuitionistic validity is rather guarded in its use of the language of set theory. There is a criticism that has sometimes been made of the intuitionistic account of the logical operators, and which is much more radical than the charge of being rough and incomplete. The intuitionistic rules themselves make use of logical operators ‘iff’, ‘and’, ‘or’, ‘every’, and ‘some’. If the operators that are used in the rules are themselves to be understood intuitionistically, then the rules seem to do little to explain the meanings of the intuitionistic connectives to a person accustomed to classical logic.
