noun The theory that reason is a source of knowledge independent of and superior to sense perception.
noun The theory that knowledge may be derived by deductions from a priori concepts (such as axioms, postulates or earlier deductions).
noun A view that the fundamental method for problem solving is through reason and experience rather than faith, inspiration, revelation, intuition or authority.
noun Elaboration of theories by use of reason alone without appeal to experience, such as in mathematical systems.