Routledge History of Philosophy Volume IV

SPINOZA: METAPHYSICS AND KNOWLEDGE 261
cast in syllogistic form, Spinoza would probably have agreed with Descartes that
the syllogism is useful only as a means of instruction, which enables others to
understand what their teachers already know, and that its proper place is in
rhetoric, not in philosophy. 36
From a discussion of Spinoza’s reasons for putting his philosophy in the form
of a deductive system we turn now to an account of the system itself. I said
earlier (p. 278) that Spinoza takes the view that, if one is to discover what is the
genuine good for human beings, one must get to know their true nature; and
further, that this implies seeing human beings within the context of nature as a
whole. In the Ethics, Spinoza (following the synthetic method) starts from certain
definitions and axioms which enable him to derive conclusions about the
universe in general, and from these, with the help of further definitions and
axioms, he derives a number of conclusions about the nature of human beings in
particular, and about what is good for us.
The first part of the Ethics is concerned with what Spinoza calls ‘God’. His
first definition, however, is not of God, but of a ‘cause of itself—though it later
emerges that to speak of God and of a cause of itself is to speak of one and the
same being. Spinoza explains that by ‘cause of itself’ he understands ‘that whose
essence involves existence; or, that whose nature cannot be conceived except as
existing’. The term ‘essence’ plays an important part in the Ethics, though it does
not receive a formal definition until Part II. In the first definition of Part I,
Spinoza is implying that the predicate P (here, existence) belongs to the essence
of S if one has to think of the nature of S as involving the predicate P. 37 Some
observations made by Descartes in his Notae in Programma quoddam
(‘Comments on a certain Broadsheet’, Amsterdam 1648; CSM i, 297) are helpful
here. The nature of contingent things, Descartes says, leaves open the possibility
that they may be in either one state or another state, for example he himself may
at present be either writing or not writing.
But when it is a question of the essence of something, it would be quite
foolish and self-contradictory to say that the nature of things leaves open
the possibility that the essence of something may have a different character
from the one it actually has.
So it belongs to the essence of a mountain that it exists with a valley; or, as
Spinoza would say, the nature of a mountain cannot be conceived except as
existing with a valley.
Let us now return to Spinoza’s definition of a cause of itself as that whose
essence involves existence. This is reminiscent of what is commonly called the
‘ontological argument’ for the existence of God; and indeed, the definition of a
cause of itself plays an important part (by way of Proposition 7 of Part I) in the
first of Spinoza’s arguments for the existence of God in Proposition 11 of Part I.
It is worth noting, however, that the term ‘ontological argument’ is used of two
different arguments, which have in common the fact that they move from a