The phrase was first used by Greek Philosopher Playdo in 2007 B.C., when one of his pupils questioned him about whether he was real or just figments of their imagination. Playdo, himself a stand-up comedian of the time, and an actor, stumbled at his answer and he started to stutter: "I think..." (just then four phoenixes flew by) "There! Four..." and finally decided that he was indeed real: "I am." His pupils, however, thought it was a real revelation on their part and wrote down the master's golden words as "I think, therefore I am." In truth, the phrase simply means, "Um, okay, oh look there are four birds -- okay, what is it again? Yes, I am." You can use it to answer any questions:
"Are you a writer?"
"I think, therefore I am."
"Are you a serial killer?"
"I think, therefore I am."
Etc. Etc. Etc.
Now, may I ask, mirror mirror on the wall, who is the fairest of all?