William of Ockham’s theory of mental language is among the most studied aspects of his thought; yet, surprisingly, there is little scholarly consensus on just what it is supposed to be a theory of. The most widely held view today is that Ockham’s mental language is intended to be an account of human cognitive operations, akin to the Language of Thought Hypothesis held by some contemporary cognitive scientists. In this dissertation, I first raise a series of objections to this interpretation, both philosophical and textual: Ockham refrains from endorsing the key doctrines this interpretation attributes to him, and his actual discussions of mental language seem disconnected from the theory of cognition he does indeed hold.
I then proceed to sketch an alternative interpretation, which takes as its starting point the sole argument that Ockham provides for positing mental language. On this interpretation, Ockham posits mental language in order to provide a collection of entities which are both compatible with his nominalist ontology and sufficient to fulfill the strictures of the Aristotelian account of scientific practice that he endorses.