I had asked this question, and it gathered a lot of answers, including some faulty and some highly technical answers. From what I can understand, no one has actually posted a sufficient proof yet. However, as I am unable to understand some of the logic used in the answers (maybe it's faulty), I can't say for sure.
Please let me know if I should accept one of the answers, or else I would like to put a bounty on the Q.
P.S. Please don't tell me why your answer is right.