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Meditation V: The Ontological Argument
1.
Essence is one thing, existence another…
The essence of something is that which makes it what it is. The essence of a triangle is
being a three-sided planar figure, for example. But it does not follow from the fact that
something has a coherent essence that there are any such things. We can talk coherently
of unicorns and dodos but there aren’t any of either.
2.
…Except when it comes to God.
Descartes says that he has a clear and distinct idea of God as the supremely perfect
being. He then says he has a clear and distinct idea that one of his perfections is
existence. So, as he then says:
“It is quite evident that existence can no more be separated from the essence of God that
the fact that its three angles equal two right angles (i.e. the sum of the internal angles of a
triangle = 180o) can be separated from the essence of a triangle, or that the idea of a
mountain can be separated from the idea of a valley.
3.
Descartes gives himself two objections.
I. Second, I can’t think of a mountain without thinking of a valley, but it doesn’t follow that
either of them exist. There’s a connection between the concepts mountain and valley.
Similarly, when you think of God, you realise a connection between the concepts God
and existence. But that doesn’t show he exists.
Descartes. Yes it does. If “I cannot think of God except as existing, it follows that
existence is inseparable from God and hence that he really exists.”
II. I suppose, out of curiosity, that there is a God. I reflect on this idea and realise
existence is a perfection. So, I must conclude God exists. But God only as part of my
supposition or as part of my idea. Compare the following. I suppose that there is a
monster living in Loch Ness. From my knowledge of biology, I deduce that it must have
had parents. Can I conclude that they exist? They exist as part of my “thought-world” but
not in reality. Similarly, just because I play with the idea of God and think that such a
thing would have to exist, it doesn’t follow that it really does.
Descartes: you don’t ever have to think about triangles but if you ever do, you’ll
realise that their internal angles add up to 180o. This is not something true just in
your thought-world – you have discovered something about what triangles really
are like. Similarly, when you reflect on God, you realise that you have discovered
what He is really like – He exists.
4.
God guarantees my clear and distinct perceptions
Descartes says that (i) God exists; (ii) everything depends on him (=is created and
sustained by him) and (ii) God is no deceiver. So, he can conclude that everything he
clearly and distinctly perceives is “of necessity” true. God has given us a faculty for
finding the truth. If you clearly and distinctly perceive that X, then X is true.
Descartes finishes by saying that this helps us in the search for knowledge. We want to
be able to discover the truth and then be sure, in future, looking back, that what we
thought was true was indeed and still is true. Otherwise, we’d have the “goldfish
problem”. We would only be able to be certain of something when we were thinking about
it. Scientific and philosophical progress would be impossible.
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Problems with the Ontological Argument - Gassendi
Gassendi puts forward an objection that is developed most famously by Kant. When
we specify the essence of something, we specify its essential properties. So, an
essential property of copper is that it is a metal, for example. Gassendi says that
existence is not really a property and hence not something that can be part of an
essence. So, when we list all those properties that are the perfections of God that
make up his essence – omnipotence, omniscience, omnibenevolence, etc. –
existence won’t be in the list because it is the wrong sort of thing to be in the list.
“It is quite all right for you to compare essence with essence but instead of you going
on to compare existence with existence or a property with a property, you compare
existence with a property. It seems that you should have said that omnipotence can
no more be separated from the essence of God than the fact that its angles equal two
right angles can be separated from the essence of a triangle. Or, at any rate, you
should have said that the existence of God can no more be separated from his
essence than the existence of a triangle can be separated from its essence.”
Gassendi makes it clear that existence is presupposed when we think of
something.
“Existence is not a perfection in God or anything else; it is that without which
no perfections can be present.” (V objections)
In other words, if we can talk about something as being perfect in some way,
then we are supposing it to exist – to exist at least in our thoughts if not in
reality.
“When you listed the perfections of God you should not have included
existence among them so as to reach the conclusion that God exists, unless
you wanted to beg the question…” (V objections)
You can’t “build in” existence into the essence of something. That’s cheating.
Descartes simply replies that existence is a property. History has agreed with
Gassendi, not Descartes. The most famous expression of the view that existence is
not a property comes from Kant (1724-1804).
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Problems with the Ontological Argument - Caterus
“Even if it is granted that a supremely perfect being carries the implication of existence in
virtue of its very title, it still does not follow that the existence in question is anything actual
in the real world; all that follows is that the concept of existence is inseparably linked to the
concept of a supreme being. So you cannot infer that the existence of God is anything
actual unless you suppose that the supreme being actually exists; for then it will actually
contain all perfections, including the perfection of real existence”
Caterus’ point is that all this type of reasoning can establish are conceptual links. There is
a necessary link between a unicorn and having a single horn. If unicorns exist, then they
with have a single horn. There is a link between the concept of God and the concept of
existence. If God exists, he exists necessarily. But you’ve got to first prove that unicorns
and God exist.
A second point Caterus makes is as follows. We cannot deduce from the concept of a lion
that it really exists, although we admit that we cannot separate existence from its essence.
But what of the concept of an existing lion? When I entertain this, does it not follow that it
exists? What about the concept of a necessarily existing lion? This line of thought is
related to Gaunilo’s objection to Anselm. It was that if I can prove God’s existence through
existence being a perfection that must belong to that which no greater than can be
conceived, then can’t I equally say that existence must belong to the concept of the most
perfect island and hence prove it too must exist?
Descartes replies to the first point that when we think about God, we clearly and distinctly
think about his nature. We discover that existence is a part of his essence. We are not
thinking about the concept of God – what we understand by “God” – but about the essence
of God or God himself.
Descartes replies to the second point by saying three things.
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

First, we should distinguish between what we might call “simple” and “complex
ideas”. A idea of a horse with wings is a complex idea because it is made up from
mixing the ideas of a horse and wings. The idea of a horse is simple as I can’t
break it down into anything else.
Second, we often do not understand the essences of things. The essence of a lion
is a case in point. We don’t know exactly what it is to be a lion.
Third, we need to distinguish between necessary and contingent existence. In
Descartes’ understanding of these terms, something exists necessarily when it
doesn’t depend on anything else for its existence and contingently when it does.
God is only the necessary existent. Everything else exists contingently because
everything only exists from one moment to the next because God wills it.
Now, Descartes says that the essence of a lion is unclear and so we can’t have a clear
and distinct idea of the essence of a lion, let alone a necessarily existent lion. So, we can’t
deduce that such a thing exists. But even if we had a clear idea of the essence of a lion,
two further things follow.


First, the idea of a existing lion is a complex one. We can think of a lion apart from
its existence (think of a lion that doesn’t exist) and so existence is not reflected in
the simple idea of a lion whereas existence is reflected in the simple idea of God.
And God is the only “simple” thing whose existence follows from his essence.
Second, there can be no such thing as a necessarily existent lion because only
God exist necessarily.
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