Descartes

That's one thing I've never particularly understood about the seeming dueling Descartes.  Between his willingness to delve into the question of existence; and on the opposite side, how he squares that with an unquestioning faith in a specific god.  It seems that he derives so much of his belief system squarely from his own thinking, which is based in Christianity.  I'm not sure if I'm correct here, but it always struck me that he was locked into the Christian faith regardless of any philosophical thoughts that may run counter to that.