In Descartes we
encounter an interesting argument, the so-called Causal Argument (CA)
from the Third Meditation. It
is the first of two arguments Descartes provides for the existence of
God, and in my opinion it has the more interesting implications (the
other is, of course, the more famous ontological argument).
The
CA goes something like this:
P1.
I have an idea of an infinite
being, God.
P2.
An effect cannot have more
reality than its cause; it must have just as much or less reality.
1.
My idea of God could not have come from:
A.
anything finite
B.
nothing
2.
My idea of God came from an infinite being.
3.
God exists.
Step
1 follows from the premisses by P2, where we define infinite things
to have more reality than finite things (Descartes is a rationalist,
after all), and finite things in all likelihood more than nothing.
Step 2 follows by a process of elimination: If my idea didn't come
from a finite thing or from nothing, all that's left is an infinite
thing. Step 3 just names that infinite being as God as
says that if my idea came from an infinite being, that being must
therefore exist.
So
here's an objection to Descartes' argument (expanded
from Gassendi's objection):
An idea of something infinite
has just as much reality as the idea of something finite, because
both those ideas are finite.
The idea of the infinite being is just a finite idea. It's content,
that it is an idea of an
infinite being, does not affect this. The content of the idea was
created by a process of adding or amplifying various perfections one
has experienced in the world.
In other words, it is a spurious infinity; one cannot experience or
even intellectually apprehend infinity, even though it is possible to
trick oneself into thinking such a thing is possible.
In
other words, there are two major objections: Step 1 is illegitimate
because something finite can indeed come from something finite; and
P1 is false because the content of the idea is not a truly infinite
God, but a spurious infinity. This first objection is the most
interesting, so I will begin with it.
To
make sense of Descartes' argument, we can make the following
(initially strange) assertion: the
idea of an infinite thing is itself infinite. In
other words, in the context of the CA, step 1 is justified because
the idea of God is infinite and thus by P2 it could not have come
from a finite source. I believe this is what Descartes is trying to
say, and that this is not a simple confusion of form and content.
But
what does it mean to say that an idea itself is infinite? How can an
idea held by a finite being be infinite? How could the mind grasp an
infinite thing not only in the content
of an idea but in its very form?
As Descartes notes in his
reply to Gassendi, one cannot “grasp” the infinite, and that is
the whole point. It is not something possible through the senses or
through the imagination, but only through the intellect. The
intellect is the only way to access infinity. But,
as noted, this is not a simple question of content, of having an idea
of infinity, but of having an infinite idea.
An
interesting implication: God is inseparable from the idea of God, or
rather, the idea of God is God.
But it is not our understanding
of our idea of God, because this is fuzzy and, as Descartes notes,
similar to a student's idea of a triangle—the student knows a
triangle has three sides, but he is ignorant of the many more
advances properties possessed by the triangle. This is a refutation
of Gassendi's objection that we only know a part of
God, because we cannot apprehend him as a whole. Rather, our
imperfect idea of God is not the idea of a part of him, but akin to
the student's idea of a triangle.
In
any case, the idea of God is God also because his essence is
existence. Here we have an interesting bridging of thought and being,
which corresponds perfectly with the above idea that an idea of an
infinite being is itself infinite.
So
we have three terms: God, the idea of God, and our idea of God. The
first two, strictly speaking, are one and the same. But our idea of
God is still infinite—it is not exactly limited
by anything, as a part would be limited by another part. Rather,
there are no parts in its content, and therefore nothing to limit the
form either, due to the weird coincidence of form and content.
This
has only been a brief exposition of
what I think is a very interesting thread in Descartes. In the future
I hope to better explore what having an infinite idea means, as well
as move a bit away from Descartes' dogmatism. In any case, I found
the account of the role of the intellect to be quite lacking in
Meillassoux (in his terms, he did not explain how it is that
mathematics/science/whatever can do what it does, etc. etc.).