¹⁰ To Mersenne, 11 Nov. 1640, AT 3. 235: see John Cottingham, ‘Introduction’, in John Cottingham (ed.), Descartes (Oxford: Oxford University Press, 1998), 6. In early modern terminology ‘philosophy’ in the broader sense (as in Descartes’s Principles of Philosophy) includes the study of the physical world (what we would call ‘science’).