Routledge History of Philosophy Volume IV

210 RENAISSANCE AND SEVENTEENTH-CENTURY RATIONALISM
asserts that the ‘main secret of the method is to distinguish the simplest things from
those that are complicated’ (AT X 381; CSM I 21).
18 Rule 12: AT X 420; CSM I 45.
19 ibid.
20 AT X 419; CSM I 45. In addition, the common simple natures include fundamental
concepts like ‘unity, existence and duration’ which may be applied either to the
material or to the intellectual simple natures.
21 AT X 421; CSM I 46.
22 AT X 427; CSM I 49.
23 Discourse, Part One, AT VI 10; CSM I 116. Descartes implies that his resolution was
made during his visit to Germany as a young man of 23, when he had his famous
series of dreams in the ‘stove heated room’ near Ulm on the Danube. These early
reflections are described in Part Two of the Discourse; see also the early notebooks
(AT X 217; CSM I 4). In Discourse, Part Three, Descartes suggests that after
postponing these metaphysical inquiries he took them up again soon after arriving
in Holland (i.e. after 1629). We know from a letter to Mersenne that about this time
he actually began to compose a ‘little treatise on metaphysics’ whose principal
themes were ‘to prove the existence of God and that of our souls when they are
separated from our bodies’: je ne dis pas que quelque jour je n’achevasse un petit
traité de Métaphysique lequel j’ai commencé étant en Frise, et dont les principaux
points sont de prouver l’existence de Dieu et celle de nos âmes, lorsqu’elles sont
séparées du corps (23 November 1630, AT I 182; CSMK 29).
24 Discussing what title to give his écrit de métaphysique (what we now know as the
Meditations), Descartes wrote: Je crois qu’on le pourra nommer… Meditationes de
Prima Philosophia; car je n’y traité pas seulement de Dieu et de l’âme, mais en
général de toutes les premières choses qu’on peut connaître en philosophant par
ordre (letter to Mersenne of 11 November 1640, AT III 329; CSMK 158). The
terms ‘metaphysics’ and ‘first philosophy’ were of course not invented by Descartes;
the latter comes from Aristotle who used it to describe fundamental philosophical
inquiries about substance and being, and the former from the name given by early
editors to Aristotle’s treatise on ‘first philosophy’ (the name ‘metaphysics’ coming
originally from the fact that in collected editions of Aristotle this work was
traditionally placed after (Greek meta) his physics). Descartes’s conception of
metaphysics was significantly different from the Aristotelian one, however, not
least (as will appear) because of its radically subjective orientation. For a
discussion of crucial disparities between Aristotelian essences and Cartesian simple
natures, see J.-L.Marion, ‘Cartesian metaphysics and the role of the simple
natures’, in J.Cottingham (ed.) Cambridge Companions: Descartes [6.32].
25 In particular by the Jesuit Pierre Bourdin; cf. Seventh Replies, AT VII 549; CSM II
375.
26 AT VII 12; CSM II 9.
27 Soliloquies, Book I, ch. 4; cf. AT VII 205; CSM II 144.
28 cf. Republic, 525. The abstract reasoning of mathematics is, for Plato, as it was
later to be for Augustine and Descartes, a paradigm of stable and reliable cognition
of the kind which sense-based beliefs could never attain. The term ‘rationalism’ is
an over-used and problematic one in the history of philosophy, but it can serve to
indicate interesting similarities between groups of philosophers: one such
indisputable similarity is the mistrust of the senses which runs like a clear thread