 Historically, the notion of the unity of consciousness has played a very large role in thought about the mind. Indeed, as we will see, it figured centrally in some of the most influential arguments about the mind from the time of Descartes to the 20th century. In the early part of the 20th century, the notion largely disappeared for a time, but since the 1960s, analytic philosophers and others have begun to pay attention to it again.