In 1637 the great philosopher, mathematician, and natural scientist René Descartes (1596–1650) published one of his most important texts, Discourse on the Method of Rightly Conducting One’s Reason and Seeking the Truth in the Sciences, commonly known simply as the Discourse. This event happened over three hundred years before Alan Turing, W. Ross Ashby, Allen Newell, Herbert Simon, Norbert Wiener, and the other giants of cybernetics and early artificial intelligence (AI) produced their seminal work. This chapter shows that in this volume Descartes not only reflects on the possibility of mechanizing mind but also identifies and takes a stand on a key question regarding the mechanization of mind. Descartes’ position was that machines (in the sense relevant to the mechanization of mind) are essentially collections of special-purpose mechanisms, and that no single machine could incorporate the enormous number of special-purpose mechanisms that would be required for it to reproduce human-like behavior.