Letter: Descartes, the Pope: epistemologists both

Sir: Andrew Brown quotes the Pope as saying in his new book that 'Descartes . . . turns his back on metaphysics and concentrates on the philosophy of knowledge' (Faith and Reason, 22 October). This suggests a misunderstanding of Descartes, and of the possibilities of philosophy. Descartes indeed had an epistemology (ie, a theory of knowledge) but above all he was the metaphysician who formulated the notoriously influential framework in terms of which both common sense and science understood the world in the centuries that followed. This was Descartes' famous dualism of nature and mind, the former consisting of law-governed matter in motion, and the latter consisting of spirit or consciousness exempted from deterministic laws.

It is true that Descartes used epistemology as a route into metaphysics, but the Pope's apparent objection to this is misplaced, as any system of metaphysics needs support from a theory of knowledge. The Pope, too, has a theory of knowledge, although philosophically it is a thoroughly disreputable one. Whether correct or not, Descartes' rationalist epistemology is far preferable to the Pope's dogmatic epistemology of revelation and authority.

Yours faithfully, ANDREW BELSEY School of English Studies, Communication and Philosophy University of Wales Cardiff 24 October