I will just point out one problem (among many) for Descartes's proof. He assumes that existence is a property. But this assumption is always challenged.
“後世哲學家對都難以推倒笛卡兒既理論” that’s right, and there is history record to support this sentence!
-- I don't see so. Whoever denies that existence is a property will reject Descartes. That includes most philosophers nowadays, under (Kant's and) Russell's influence.
I concede that there are people who argue that Descartes is not taking existence as property. But then the burden is on Descartes -
Again, similarly, whoever denies the Cartesian rationalism, or denies that intuition provides epistemic justification for (certain) beliefs, can easily reject Descartes' proof. ('clear and distinct idea' is doing too much job) Also, I tend to deny that we can make coherent sense of what perfection is. This is a silly little linguistic trick.
