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samivel	166772.  Tue Apr 17, 2007 3:57 am Just playing Devil's Advocate here, but we can't be certain we exist. How do we know that what we think of as our own personal existence isn't some big con?
Long Haired Hippy	166809.  Tue Apr 17, 2007 5:17 am jaygeemack wrote: According to Descartes, the only thing I can be certain of is that I exist. "I am conscious of my existence, therefore I must exist." We cannot be certain of anything else. Descartes did not say that. Anything you believe that relies on your perception may be the result of a deceptive spirit feeding you false information. However there are a number of mathematical proofs and dedutions from the realm of pure logic that are not reliant on perception and as such we can be certain of them too. E.g. in planar geometry the sum of the angles in a triangle is 180 degrees.
jblackley	166942.  Tue Apr 17, 2007 10:57 am Long Haired Hippy wrote: E.g. in planar geometry the sum of the angles in a triangle is 180 degrees. In your world, LHH, in your world.
mckeonj	167013.  Tue Apr 17, 2007 2:51 pm Nowhere is the sum of angles in any triangle 180 degrees (or 2pi radians or 100 grads). Nowhere on this earth, that is. Where is the perfect plane on which to draw the perfect triangle?
Efros	167106.  Tue Apr 17, 2007 6:21 pm Like most other mathematical concepts its all in yer head!
Izzardesque	169768.  Thu Apr 26, 2007 1:30 am I'm fairly certain that I don't like Brussel Sprouts.

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