Frege's Critics of Ideational Theory of Meaning and Wittgenstein's PLA

Gottlobe Frege is considered as one of the first incisive critics of psychologism in logic and semantics. In this article, Frege's criticism of Ideational Theory of Meaning is discussed. According to Frege, this theory invalidates truth, but also problematizes meaning and the possibility of communication as well. These critiques are framed through Frege's main conceptual frameworks, namely, that of logisim and the first theorem of Grundlage der Arithmetik, by which he distinguishes between the objective/logical and the subjective/psychological. These critiques are then compared with later Wittgenstein's Private Language Argument (PLA). We argue that a detailed account of Frege's concept of idea illustrates that his assumptions about the relation between the inner world (Innenwelt) and language could be criticized. Through discussing "private definition of a sign'', ''following a rule'' and ''criteria of the identity'', Wittgenstein's definition of the Private Language and his arguments against it are analyzed so that we can critically study these assumptions.