Ontological Categories and the Problem of Expressibility with Øystein Linnebo

Frege famously held that ontological categories correspond to logico-syntactic types. Something is an object just in case it can be referred to by a singular term, and likewise for all the other ontological categories. However, this view faces an expressibility problem. In order to express the view, we need to generalize across ontological categories; but according to the view itself, any one variable can only range over a single ontological category. This chapter provides a sharp formulation of the problem of expressibility. It shows that there is no easy way out, and then explores some of the hard ways out.