This position paper examines René Descartes' theory of reality as presented in his *Meditations on First Philosophy*. It analyzes Descartes' skepticism, his arguments for the existence of a thinking self ('Cogito Ergo Sum'), and the implications of his representationalist view. The paper also considers objections to Descartes' theory raised by philosophers like Thomas Hobbes and Descartes' responses to these criticisms. Ultimately, it argues that Descartes' theory leads to a mind that questions everything, including its own existence, and defines reality as encompassing both present and past experiences.