Routledge History of Philosophy Volume IV

162 RENAISSANCE AND SEVENTEENTH-CENTURY RATIONALISM
apply to any area of enquiry. The problem was that, during the Middle Ages, the
topics came to be associated very closely and exclusively with rhetoric, and their
relevance to scientific discovery became at first obscured and then completely
lost. The upshot of this was that, for all intents and purposes, the results of
Aristotelian science lost all contact with the procedures of discovery which
produced them. While these results remained unchallenged, the problem was not
particularly apparent. But when they came to be challenged in a serious and
systematic way, as they were from the sixteenth century onwards, they began to
take on the appearance of mere dogmas, backed up by circular reasoning. It is
this strong connection between Aristotle’s supposed method of discovery and the
unsatisfactoriness not only of his scientific results but also of his overall natural
philosophy that provoked the intense concern with method in the seventeenth
century. 10
DESCARTES’S NATURAL PHILOSOPHY
Descartes’s account of method is intimately tied to two features of his natural
philosophy: his commitment to mechanism, and his commitment to the idea of a
mathematical physics. In these respects, his project differs markedly from that of
Aristotle, to the extent that what he expects out of a physical explanation is
rather different from what Aristotle expects. This shapes his approach to
methodological issues to a significant extent, and we must pay some attention to
both questions.
Mechanism is not an easy doctrine to characterize, but it does have some core
theses. Amongst these are the postulates that nature is to be conceived on a
mechanical model, that ‘occult qualities’ cannot be accepted as having any
explanatory value, that contact action is the only means by which change can be
effected, and that matter and motion are the ultimate ingredients in nature. 11
Mechanism arose in the first instance not so much as a reaction to scholasticism
but as a reaction to a philosophy which was itself largely a reaction to
scholasticism, namely Renaissance naturalism. 12 Renaissance naturalism
undermined the sharp and careful lines that medieval philosophy and theology
had drawn between the natural and the supernatural, and it offered a conception
of the cosmos as a living organism, as a holistic system whose parts were
interconnected by various forces and powers. Such a conception presented a
picture of nature as an essentially active realm, containing many ‘occult’ powers
which, while they were not manifest, could nevertheless be tapped and exploited
if only one could discover them. It was characteristic of such powers that they
acted at a distance —magnetic attraction was a favourite example—rather than
through contact, and indeed on a biological model of the cosmos such a mode of
action is a characteristic one, since parts of a biological system may affect one
another whether in physical contact or not. The other side of the coin was a
conception of God as part of nature, as infused in nature, and not as something
separate from his creation. This encouraged highly unorthodox doctrines such as