Just to complicate your thoughts further, I'll point out that there are some mind-blowing theories involving quantum mechanics, cosmology, and the anthropic principle which suggest that the universe exists only because SOMEone is around to observe and believe in its existence.

Another theory, actually being treated seriously by cosmologists even if not generally accepted, is that the universe and we ourselves are simply part of a vast hologram or computer program created by ancient aliens for unknown reasons. See, e.g., "Before the Big Bang," by Brian Clegg, and "The Goldilocks Enigma," by Paul Davies.

I'm willing to admit that possibility that the rest of you may be part of a hologram, but am still reluctant to admit it about my own mind. :-)