Mind (mens) – also called “rational soul” – traditionally identified with intellect (intellectus) and reason (ratio), was considered since antiquity the seat of the highest psychic powers. It was not only the part of the soul that was immaterial (not requiring corporeal organs for its operation), and so indestructible, but was also the source and instrument of the highest kind of human perfection – understanding – that came with the highest kind of bliss or happiness. The mechanistic view of nature challenged philosophers to revise or, as the case may be, break loose from inherited conceptions of mind and its relation to the world that did not really fit with it. Among the first to meet this challenge was Descartes, who laid out the conceptual framework within which subsequent discussions of mind and its nature were conducted. Descartes redefined mind in terms of thought in a broad sense so that it includes not just intellect, but also the will, sense perception, imagination, and feeling. He thus transformed the notion of the mind in ways that directly or indirectly have influenced all subsequent theorizing on the human mind and its powers in the Western tradition. Nevertheless, the continuities between his conception of mind and Scholastic philosophical psychology are greater than his terminological innovations may seem to suggest (see Carriero 2009). This article focuses on mind mainly in the restricted sense of intellect, understanding, and epistemic subject.

1.Mind in the Early Writings

Descartes’ concern with understanding and mind grows out of his early work in mathematics and philosophy of nature, particularly his project of developing a general method of scientific discovery for which mathematics – arithmetic/algebra and geometry – provided a paradigm (see Rules for the Direction of the Mind). The unfinished methodological project was later replaced by an even more ambitious metaphysical project announced in the Discourse on Method (1637) and worked out in the Meditations on First Philosophy (1641).