would be F. But apart from this, it also sets up the claim that (27) and (29) concern some
entity or truth independent of the mind. If there really is some entity or truth that logically
requires that God exist, then there would be a contradiction in objective reality (not just
in our ideas about it) if God did not.
Like (21), (26) is dubious but dispensable. All Descartes needs is (27), which we can
recast as
27a. There is a “true and immutable nature” P which includes all perfections and is
(uniquely) such that if it exists, it has an instance,
whence he can reason that
- P exists. (27a, simplification)
- If P exists, it has an instance. (27a, simplification)
- P has an instance. (31, 32, MP)
Traits of our idea of God are supposed to assure us that it captures a “true and immutable
nature.” Why is (27a)'s second conjunct supposed to be true? One story Descartes tells is
the (18)–(19) argument. But in at least one place, he tells another story about why
existence is uniquely inseparable from the divine essence:
end p.101
It is not true that essence and existence can be thought the one apart from the other in
Godbecause God is His existence. (HR II 228)
That God = God's existence explains the inseparability of God's essence and God's
existence only if God = God's essence—a standard part of the doctrine of divine
simplicity Descartes inherited from his Jesuit education. So what Descartes is really
saying here is that the divine essence = the divine existence. The reason (27a) is true,
then, could be that if there is a divine nature, it is identical with the existence of God. If
this is so, then if there is in extramental reality such a nature, there is also such an
existence—and so God exists. Perhaps Descartes' doctrine of divine simplicity, asserted
in Meditation III, can help his argument in Meditation V.
Descartes: Objections and Replies
Publication of the Meditations led to a series of exchanges between Descartes and
prominent intellectuals. The best criticisms of Descartes' argument from perfection came
from Pierre Gassendi and Johannes Caterus. Caterus wrote:
Though it be conceded that an entity of the highest perfection implies existence by its
very name, yet it does not follow that that very existence is anything actual in the real
world, but merely that the concept of existence is insepatably united with the concept of
highest being. (The) complex “existing lion” includes both lion andexistence, and
includes them essentially, for if you take away either it will not be the same complexdoes
not its existence flow from the essence of this composite “existent lion”? Yet (this) does
not constrain either part of the complex to existTherefore, also, even thougha being of
supreme perfection includes existence in the concept of its essence, yet it does not follow
that its existence is anything actual. (HR II, 7–8)