Abstract

In their book on Descartes’s changing mind, Peter Machamer and J.E McGuire argue that Descartes discarded dualism to embrace a kind of monism. It is intriguing to investigate if the master of dualism could have changed his mind about the central aspect of his system. After reviewing the position of the authors, we will consider how and in what terms Descartes did not go back on his favorite doctrine but may have fooled himself about the nature of his dualism. It is my contention that the so-called problematic Cartesian dualism has its origin in the lack of proper definition of mind and body as substances and the role of their respective attributes, thought and extension in the definition of the substances. The main answer to Machamer and McGuire’s thesis is that Descartes could develop his epistemology of mind and body independently of a metaphysics of substance and its attributes. In other words not only did Descartes not change his mind, but he persevered and enriched his dualist metaphysics. The subsidiary answer to the authors is that the concessions given by Descartes to the opponents of his dualism can be found in earlier works, but, pace the authors, they did not cause him not to develop his dualism in the first place.