A common argument against the existence of unconscious mental states before, during, and after Freud's time was what I call the 'semantic objection," that "mind" simply means "consciousness' so postulating unconscious mental states is self-contradictory and a misuse of the term "mental." Freud returned again and again to dispute the semantic claim. In this chapter, I explore the history of this argument and document how common and salient it was, thus explaining why Freud took it so seriously and felt he had to address it as the starting point for his challenge to Cartesianism.