Originally Posted by Caltex

The so called philosophical proofs for a god are all based on circular logic. Descartes in particular allows his faith to delude him, and lead to illogical arguments. These arguments are easily shown to be false.

Here are Descartes arguments:
1. I have an idea of a perfectly good God
2. That idea must have a cause.
3. Nothing comes from nothing.
4. The cause must be something that can conceive the perfect in which is conceived
5. I am not perfect, and therefore cannot on my own conceive the perfect
6. Therefore I could not be the cause of the idea.
7. There must be a cause that is infinitely perfect.
8. God exists because he must be the cause.

NOW, why that is wrong:
If these conclusions were true, then anything that can be imagined to exist, must exist, as he claims it cannot have originated with him. I imagine a perfectly good Flying Spaghetti monster, I could not have imagined the perfect spaghetti monster on my own!!!

The fact is, that the idea did originate from something, it originated within his own mind. The brain is capable of imagining the concept of perfect, just isn't able to achieve it.

Further Descartes actually refutes his own god proof in the same philosophical line in which he claims to prove him, with the denial of his own existence arguments, concluding the only universal truth is that he knows he exists.

All the proofs are based off the assumption that the existence of logic, or certain conceptions can somehow prove a god, which are preposterous.