additional ontic grounds for Descartes’essence. This suggests to me that, by Des-
cartes’lights, Descartes himself is his own ultimate ontic essence.^55
There are two related complications with this interpretation, however. First,
Descartes presents a version of the ontological argument that seems to turn on
identifying God’s existence and essence, but also appears to overgeneralize if, in
created substances, there is not a real distinction between essence and existence.^56
(We’ll discuss this argument in section 9.5, and whether it overgeneralizes, as well as
how relevant the identity of God’s essence with God’s existence is for the success of
the ontological argument.). It is hard to make sense of a real distinction between
existence and essence in created substances if each created substance is its own ontic
essence. And there are places where Descartes suggests that the relation between
essence and existence in creatures is different from that in God; e.g., in theFirst Set of
RepliesDescartes (1991a: 83) says that“we fail to notice how closely existence belongs
to essence in the case of God as compared with that of other things.”On the other
hand, there are passages in which Descartes (1991b: 280) denies that the essence and
existence of created things are distinct outside of thought.^57
Second, Descartes also seems to accept that truths about the essences of created
substances are necessary, even though the existences of created substances are
contingent. Given the definition of“ultimate ontic essence,”the claim that the
propositional essence of Descartes is necessary although the existence of Descartes
is contingent is consistent with the claim that Descartes is his own ultimate ontic
essence.^58 However, if this is the case, then in those worlds in which Descartes does
not exist, Descartes’total propositional essence must lack an ontic ground. And in
this case, it is unclear what, if anything, would groundx’s propositional essence in
those worlds. Can an actually grounded fact be only contingently grounded?
Let us now explore the second candidate. Suppose that David Lewis is a hylo-
morphic compound of some sort, and that one of his constituents is asubstantial
form.I’ll assume that substantial forms are particulars rather than universals, and
that they are not transferable: necessarily, ifxhasSas its substantial form, then,
necessarily, anyythat hasSas its substantial form is identical withx. The second
candidate is substantial form construed in this way.^59
(^55) Note that Secada (2000: 190, 193–4) calls Cartesian substances“determinable essences.”
(^56) See Nolan (2015) for a related worry about how Descartes’views on existence and essence com-
promise his ontological argument. 57
See Secada (2000: ch. 8) for a lengthy and informative discussion of Descartes’view of existence and
essence in creatures. 58
Provided that singular propositions about objects can exist in worlds in which those objects do not
exist. We discussed this issue in section 9.3. 59
Wisnovsky (2003: 11) says that both“perfection and essence can each be understood as referring to a
thing’s substantial form.”Gilson (1952: 74) says that form can be taken as essence when it is the proper
object of intelligible definition. Knuuttila (2012: 63) says that, for Aquinas, form determines essence.
Pasnau (2011: 551) notes that many philosophers took the substantial form of a thing to in some way
account for or determine the essence of that thing. (He also notes that this is not the sole role that
substantial forms are invoked to play.) Adams (1994: 100) says that, for Leibniz, essence is to be either