Routledge History of Philosophy Volume IV

SPINOZA: METAPHYSICS AND KNOWLEDGE 259
CSM ii, III). Synthesis, on the other hand, is the reverse of this; as Descartes
explains (ibid.) one starts with first principles and demonstrates conclusions from
them, employing ‘a long series of definitions, postulates, axioms, theorems and
problems’. Descartes stated a preference for the analytic method, which was, he
said, the method that he had used throughout the Meditations (CSM ii, 111).
However, in response to Mersenne’s suggestion he concluded his reply to the
Second Objections by arguing ‘in synthetic style’ for some of the propositions
argued for in the Meditations. But he insisted (CSM ii, 113) that these proofs
were not a substitute for the Meditations, and said indeed that the analytic
reasoning used in that work was superior.
Spinoza, on the other hand, clearly thought that the best way in which to
discuss ethics was by means of the synthetic method. One naturally asks what
Spinoza hoped to achieve by the use of this method; that is, what he thought he
would gain by presenting his philosophy in the form of theorems, derived from
definitions and axioms. The answer may seem to be obvious. Spinoza does not
explain how he viewed axioms, but there can be no doubt that he would have
agreed with the remarks made by his friend Lodewijk Meyer, in the Preface that
Meyer wrote to Spinoza’s geometrical version of Descartes’s Principles. In that
Preface, Meyer said (G i, 127) that axioms are ‘statements so clear and evident
that all who simply understand correctly the words that they contain can in no
way refuse their assent to them’. Axioms, in short, are self-evident truths, and
Spinoza’s aim in the Ethics is to derive from these, by deductive means, other
propositions whose truth is not self-evident. In this way, he will demonstrate the
truth of these propositions. 30
I said just now that this explanation of Spinoza’s use of the geometrical
method may seem to be obvious. By this I did not mean that the explanation is
wrong; I meant only that there is more to be said. Spinoza has a deeper reason
for using the geometrical method, as can be seen from the Preface to Part III of
the Ethics. Here (G ii, 138) Spinoza discusses his application of a geometrical
method to human emotions, and contrasts his approach with that of those who
‘prefer rather to abuse and ridicule the emotions and actions of men than to
understand them’. Such people, he says, will find it extraordinary that he should
want to demonstrate with sure reasoning (certa ratione) what they merely
condemn rhetorically. But, he continues, human emotions follow from the same
necessity and power of nature as other things do, and ‘acknowledge certain
causes through which they are understood, and have certain properties equally
worthy of our knowledge as the properties of any other thing, the contemplation
alone of which delights us’. This shows that Spinoza thinks that the geometrical
method, although it is certainly a means of establishing truths, is more than that.
The person who has grasped the reasoning of the Ethics, Spinoza claims, will not
just know the truth of a number of propositions, but will understand why things
are as they are. In short, Spinoza is concerned not just to establish truths but to
offer explanations.