Routledge History of Philosophy Volume IV

262 RENAISSANCE AND SEVENTEENTH-CENTURY RATIONALISM
definition of something to an assertion of the existence of what is defined. In the
version which is familiar from Descartes’s fifth Meditation (CSM ii, 44–9) the
argument is based on the definition of God as a most perfect being, together with
the thesis that existence is a perfection. This is basically the same as the argument
put forward by Anselm, in the eleventh century AD, in his Proslogion, although
there the argument proceeds from the definition of God as ‘that than which
nothing greater can be thought’. 38 Spinoza, on the other hand, is arguing from the
concept of a necessary being. His argument is that a necessary being is a being
which has to be thought of as existing; and that which has to be thought of as
existing, necessarily exists. It may be added that another seventeenth-century
rationalist, Leibniz, put forward both versions of the argument, though he
declared his preference for the second version. 39
The concept of a cause of itself is interesting, not only for the relation that it
has to Spinoza’s version of the ontological argument, but also because it
illustrates his distinctive views about causality. Someone who (like Hume or
Kant 40 ) takes the view that a cause must precede its effect in time will find the
concept of a cause of itself self-contradictory; for how can something first exist,
and then cause its own existence? Spinoza, however, does not view causality in
this way; his view is a version of what it is usual to call the rationalist theory of
causality. According to this theory, to state the cause of X is to give a reason for
X’s existence or nature. So much might be generally agreed, if this is taken to
mean that to give a reason is to answer the question ‘Why?’, and that in stating
the cause of something one is answering such a question. What is distinctive
about the rationalist theory of causality is the view that, in giving such a reason,
one is doing what geometers do when they state the reason for the truth of some
geometrical proposition—as when, for example, it is said that the reason why the
base angles of a certain triangle are equal is the fact that the triangle in question
is isosceles. In such a case, the relation between the triangle’s being isosceles, on
the one hand, and having base angles which are equal, on the other, is a timeless
relation; and Spinoza takes the view that such a relation holds in every case of a
cause-effect relation. This is what he means when, in the second proof of the
existence of God in Proposition 11 of Part I of the Ethics, he uses the phrase
‘cause, or reason’ (causa seu ratio; G ii, 52–3), where ‘reason’ is used in the nontemporal
sense that has just been described. 41 This being so, to speak of a cause
of itself is not to speak of that which exists before it produces itself; rather, it is
to speak of that whose existence is self-explanatory.
Why Spinoza should have taken this view of the nature of causality can only
be conjectured, but it does not seem fanciful to relate his view to the science of
his time. I have said already that this science was mathematical in character (p.
281); now, many causal propositions belong to the sciences, and it would have
been tempting to see the causal propositions asserted by physicists as not
different in kind from the propositions asserted by geometers, and from this to
argue that absolutely all causal propositions are to be viewed in this way. It may
be added that the influence of the rationalist theory of causality was still felt in