In Descartes' Meditations on the First Philosophy, his "First Meditation" focuses on phenomenon that can be called into doubt. In this section, Descartes proceeds to discuss reality and illusion, and the questions these thoughts raise. In the paragraph that begins with the line: "a brilliant piece of reasoning!," Descartes analyzes or draws connections between humans who are sane and insane, and sleep and dreams versus wakefulness and reality. In this paragraph, Descartes posits that a …showed first 75 words of 563 total…

…showed last 75 words of 563 total…to say that he can distinguish between the two, through the use of his analogy that "while asleep; as he begins to suspect that he is asleep". This usage of the analogy suggests there are periods when one can differentiate between illusions and reality. From this, questions emerge regarding skepticism and doubt seem to be stifled by the fact that Descartes appears to choose common sense and belief at the conclusion of the "First Meditation."