conuly

*laughs*

We were discussing the Cartesian Circle, which is how Descartes' theory got into trouble. Basically, Descartes says that even if there's an evil force out there making stuff up, the one thing this force can't make up is that he exists. Which makes sense. It's hard to believe that you're making something think that he or she exists when really they don't.

And then Descartes says that this evil demon can't make him think of things with more reality than exists in nature. Or something. Basically, ideas come from something, and they can't come from something with less reality than the thing the idea is about. An evil demon can make you believe in things less real than the evil demon, but he can't make you believe in an infinite god. So god must exist. And since god isn't a deciever, the real world must exist too.

Except how do you know that ideas can't come from nothing? Because if they could, god would be a deceiver. Yeah, but weren't you trying to prove god exists?

Anyway, the professor went over this several times, with three different projector screens, so that even the slowest student would understand how this is a vicious circle. I played freecell. Just when I was starting to wonder if these precautions were really necessary...

Professor
You know who
Me

P: So, you can see it's a circle. Any questions?
Y: So... it's a circle...
P: Yes.
Y: Is that bad?
M: *blink*
P: Yes, it's bad. Because then you haven't proven anything.
Y: But no, it's good! It's how you prove god exists!
M: *gigglesnorts, literally*

They spent a few minutes with the professor trying to explain why you can't prove god exists by saying that you know you aren't being deceived because that would mean god's a deceiver.

Sorry about the capitalization, me lazy.