ABSTRACT
Rene Descartes saw the Cogito as a victory over the evil specter of the evil demon. An evil demon can try to deceive students about everything. Supposedly, there are no limits to the powers of deception possessed by Descartes's evil demon. Descartes himself used a somewhat different argument in order to motivate external world skepticism. He gave students what has come to be termed the dreaming argument. Descartes was an internalist, and his skeptical arguments reflect this preference. For instance, he worries about a kind of dreaming that fools students into thinking that students are having normal experiences and hence into thinking that they have good reasons for believing that there is an external world. He thought that it could be done. Although he took skeptical arguments seriously, he thought that he could answer them.
