How should the mathematical fictionalist approach physical theories, such as perhaps string theory, that do not seem to be about concrete observable objects? One possible response, assuming the lack of empirical import of such theories, is simply to reject that they are physical theories, and as such they are not the sorts of theories for which the mathematical fictionalist needs to provide a nominalistic counterpart. In other words, until the moment in which such theories acquire the relevant empirical import, they need not worry the mathematical fictionalist. Theories of that sort would be classified as part of the mathematics rather than the physics.