version of that argument, based on remarks in Descartes’Fifth Meditation.^84 Premise 1:
I have a clear and distinct idea of God. Premise 2: having a clear and distinct idea of
xjust is grasping the essence ofx, i.e., knowing the total propositional essence ofx.^85
Interim conclusion: so I know the total propositional essence of God. Premise 3: any
total propositional essence is necessarily true, independently of whether the posses-
sor of that essence exists; this is where the Cartesian view of essence, discussed in
section 9.3, comes into play. Premise 4: the total propositional essence of God is that
God exists (in the manner in which God exists). Conclusion: so God necessarily exists
(in the manner in which God exists).
There are many ways to resist this argument. One could embrace what I called
“existentialism”in section 9.3 and thereby deny premise 3. Fittingly, this is a plausible
move to make with respect to a parallel argument for the necessary existence of
Dasein. If truths of essence are not necessary but rather contingent on truths of
existence, then things can have their modes of being essentially without necessarily
existing. (Conversely, if one accepts the possibilist view described in section 9.3, one
might happily accept that there is a mode of being that as a matter of necessity
everything enjoys.)
But with respect to this ontological argument, the more cutting responses might be
to reject premise 1 or premise 2.^86 This might be even clearer if we consider a second
version of the ontological argument.
Here is a second Cartesian ontological argument. Premise 1: I have a clear and
distinct idea of God. Premise 2: having a clear and distinct idea ofxjust is grasping
the essence ofx, i.e., knowing the total propositional essence ofx. Interim conclusion:
so I know the total propositional essence of God. Premise 3: for any total propos-
itional essence of something, it is possible that this something exists. (Essences
correspond to possible existents.) Premise 4: the total propositional essence of
(^84) Descartes (1991a: 44–9) contains theFifth Meditation. There are some similarities between the
reconstruction I offer here and Curley’s (1978: 141–69); the most important similarities are that there
can be truths about the natures or essences of things regardless of whether they exist, and that our clear and
distinct perceptions of these essences are veridical. Interestingly, Doney (1993) argues that,“in a sense and
with qualifications,”there are two different versions of the ontological argument to be found there; he calls
these two arguments“argument A”and“argument B.”The argument I discuss here is not formulated in
the same way as either Doney’s argument A or B, but it is much closer to his A than his B. Schmaltz (2014:
21685 – 17) responds to Doney (1993).
Gewirth (1998: 97, fn. 72) notes that a crucial part of Descartes’ontological argument in theFifth
Meditationis that our idea of God represents a real essence. In Descartes’(1991a: 83) response to Caterus,
he reaffirms that he takes us to have a grasp of the essence of God. See Doney (1993: 81–2) for a discussion
of Descartes’response to Caterus. Schmaltz (2014) provides a general overview to Descartes’ontological
argument; see also Koistinen (2014: 230–6). Secada (2000: 163) says that our idea of God is an idea of
God 86 ’s essence.
Aquinas is committed to rejecting either premise 1 or premise 2 of this argument because he holds
that we do not have a grasp of God’s essence, not because His essence does not imply existence. See
Aquinas’s (1948: 11–12)Summa Theologicapart 1, question 2,first article and Aquinas’s (1991: 82)Summa
Contra Gentilesbook I, chapter 11, section 5, andfinally Aquinas (1994: 69–70). See also Pasnau and
Shields (2004: 64).