Routledge History of Philosophy Volume IV

8 RENAISSANCE AND SEVENTEENTH-CENTURY RATIONALISM
Given a knowledge of the existence and nature of the supreme being, the task
of the rationalist was, as it were, to build on this foundation by deriving the
consequences which followed. But there were important differences between the
ways in which the seventeenth-century rationalists saw this being. For all of them
except Spinoza, the supreme being was a personal deity, creator of the universe,
and choos ing freely to create it. Spinoza argued that such a concept was
incoherent, and that a consistent account of the necessary being must present it
as an impersonal being, within which particular things exist, and which cannot
rationally be regarded as exercising free will. This was clearly opposed to
orthodox Christian doctrine; however, one should not exaggerate Spinoza’s role
in ending the predominance of Christian ideas in philosophy. 36 His philosophy,
at first bitterly attacked, was later largely forgotten until its revival by the
German romantics towards the end of the eighteenth century. A more important
factor in the loosening of the ties between Christianity and philosophy was the
rise in the seventeenth and eighteenth centuries of deism; that is, of belief in a
creative deity, unaccompanied by any belief in a divine revelation. With this,
rationalism had little to do. 37
Today, there is widespread agreement that the seventeenth-century rationalists
failed to provide an a priori proof of the existence of God, however that God
was conceived by them. It would also be agreed that they failed to find, by pure
reason, necessary connections between the nature of God and the laws of science. 38
But these failures do not deprive their philosophy of all value. For them, science
was not merely something that had to be justified; it was also something that
posed problems, and their attempts to solve these problems are still found
interesting.
The question whether human beings can strictly speaking be called free had
long exercised philosophers. Before the seventeenth century, the problem took a
theological form. Philosophers, such as Boethius in the sixth century AD and
Lorenzo Valla in the fifteenth, asked how human freedom could be consistent
with the foreknowledge and providence of God. These problems continued to be
discussed in the seventeenth century, but in that era there was a new problem of
freedom. For the new science, all physical events were determined by necessary
laws; so the question arose how there could be any human freedom, given that
we are (even if only in part) physical objects. Spinoza and Leibniz offered
solutions which took the form of what are now called ‘compatibilist’ theories,
arguing, in very different ways, that freedom and determinism can be
reconciled. 39
Science posed another problem for the seventeenth-century rationalist. One of
Descartes’s best known theses is his view that mind and body are ‘really
distinct’, that is, that each can exist without the other. Behind this, there lay a
view about scientific explanation: namely, that bodies are to be understood solely
in terms of physical concepts, and minds solely in terms of mental concepts. 40 To
explain physical events, therefore, we do not need to postulate the intervention of
incorporeal agents (such as, for example, the planetary intelligences). But this