ABSTRACT
This chapter discusses the development of Wittgenstein’s philosophy of logic with reference to the color-exclusion problem, relating to propositions in the case of which the attribution of a property excludes the simultaneous attribution of a property of the same kind to the same object. This led Wittgenstein, first, to consider the possibility of logic as a phenomenological investigation that would establish which properties have this character of mutual exclusion. While this would have saved the Tractatus’ assumption of the independence of elementary propositions and the associated account of truth-functions, however, it would have compromised its conception of the non-substantiality and formality of logic. Recognizing this, Wittgenstein rejected elementary propositions and introduced the notion of propositional systems to account for relevant kinds of cases. But this soon revealed further problems concerning logic, pertaining to logical generality, the universality and topic-neutrality of logic, the status of logical languages and models, and the conception of logic as a rigorous non-empirical investigation. Eventually, dealing with these problems led Wittgenstein to develop his mature philosophy of logic. I conclude with comments on the new life that can be given to Wittgenstein’s propositional systems in the context of his mature philosophy of logic.
