Thanks for the reference to Descartes' Meditations on the first philosophy, Greg... I have not looked at it in a long time... and I should have.

Wiki has a nice synopsis of this work, and I'm wending my way through it bit by bit.

This seems to be relevant:

Meditation III

Argument 1

I have an idea of God (an infinitely perfect substance).
That idea must have a cause.
Nothing comes from nothing.
The cause must have at least as much formal reality as the idea.
I am not infinitely perfect.
I could not be the cause of the idea.
There must be a cause that is infinitely perfect.
God exists.

Argument 2

I exist.
My existence must have a cause.
The cause must be either:
   a) myself
   b) my always having existed
   c) my parents
   d) something less perfect than God
   e) God
Not a. If I had created myself, I would have made myself perfect.
Not b. Continued existence does not follow from present existence.
Not c. This leads to an infinite regress.
Not d. The idea of perfection that exists in me cannot have originated from a non-perfect being.
      e. God exists.

...and this...

I find that I am "intermediate" between God and nothingness, between the supreme entity and nonentity. Insofar as I am the creation of the supreme entity, there's nothing in me to account for my being deceived or led into error, but, inasmuch as I somehow participate in nothing or nonentity - that is, insofar as I am distinct from the supreme entity itself and lack many things - it's not surprising that I go wrong. I thus understand that, in itself, error is a lack, rather than a real thing dependent on God. Hence, I understand that I can err without God's having given me a special ability to do so. Rather, I fall into error because my God-given ability to judge the truth is not infinite. (Descartes, Meditation IV: On Truth and Falsity).

So... have at it!
ttr