Abstract

The transparency thesis – i.e. the doctrine that every mental state is necessarily conscious – was a widespread view in early modern philosophy. In this paper, I inquire into the role of mental transparency in the philosophies of John Locke and René Descartes. I begin by sketching a shared Lockean-Cartesian picture of mind as it pertains to the psychological or structural aspects of consciousness. I then distinguish mental transparency from the closely related concept of epistemic transparency and argue that the thesis must allow for different degrees of conscious awareness, which is needed to address some of our uneasy intuitions. Afterwards, I examine Locke’s and Descartes’s reasons for adopting transparency in their respective philosophies. In the case of Descartes, I present consciousness as a necessary condition for knowledge of our own minds in the larger context of his epistemological goals in the Meditations. In the case of Locke, I examine three of his arguments in order to illustrate the indispensable role of transparency in his polemic against central Cartesian doctrines such as innatism and the thesis that the soul always thinks.