Some people would say that it's precocious to start a post with the most well-known of Cartesian quotes. If you are one of those people, you should go watch Blade Runner and see what you start thinking. Myself, I just watched Ghost in the Shell, which treads a lot of that same ground, just like a lot of the elements in the PS2's Xenosaga. After being subjected to as many years of Matrix-mania as I have been, and "the world is an illusion"-style philosophies that would be more welcome after a viewing of The Truman Show, it's always nice to get back to the classic question of, "What is human?"
As you can tell, I'm on a bit of an anime kick right now; no doubt the result of my complete and utter loathing of the consistent stream of complete and utter garbage that Hollywood churns out year after year. After watching a movie in the theater, I find that more often than not I end up thinking about whether or not it was a good movie, and then I never think about it again. American studios don't like to put out films that require any brain-activity beyond basic autonomous functions. As such, making a film that would require the audience to consider cracking a book by Descartes... well, that's never going to happen.
Of course, I wouldn't wish that on anyone. Reading works by Descartes should only be done by philosophy majors who want to write books on why Descartes was wrong, so they can be shelved at the local bookstore right alongside the fifty other books by their classmates on that exact same subject.
Anyway, I've been on this bizarre run lately, where I've been plumbing my DVD collection for films with any philosophical subject matter to them at all. I mean, Fight Club may be totally nihilistic, but at least it's got something going for it. A.I. is another one of those Blade Runner-style films in which robots become so human that finding the difference between the two becomes essentially pointless. In a few months, the last few discs of the Platinum edition of Evangelion should be out, so by then I should know whatever the fuck it's about.
What it eventually comes down to is the notion of the Polyvarius. It looks like a Stradavarius. It sounds like a Stradavarius. ... It smells like a Stradavarius! If you've got something that's artificial but can't be distinguished from the real thing, doesn't that pretty much define it as being real? ... Of course, none of this really hits on the notion of existence and Descartes and what-not. I'm just rambling because I've got a bitch of a headache, and I'm going to take about eight Advil and go to bed.