Carnap’s Methodological Platonism: An Explication of
his Linguistic and Semantic Realism

Abstract: In this paper, I will argue that Carnap is a methodological Platonist despite his neutralism in the Platonism/nominalism debate. The sense of ‘Platonism’ that I attribute to Carnap has two aspects. He is a Platonist both in a linguistic and semantic sense. For him, it is preferable that the language of science be augmented with a language for numerical singular terms—whether or not these can be understood nominalistically. In this sense, Carnap is a linguistic Platonist. He is also a semantic Platonist since he accepts a semantic metalanguage which allows that number-symbols designate numbers understood as objective, extra-linguistic, and mind-independent entities. I will also show that Carnap’s methodological Platonism leaves his ontological neutralism intact.