QUOTE(A.U.K @ Jul 26 2008, 08:10 AM)

QUOTE(petrat @ Jul 26 2008, 08:08 AM)

You did if you think that you did!

Very Good Petrat ...I like that very philosophical train of thought...
Hmmm ... when Descartes said 'I think, therefore I am' what he meant was that if there was thinking going on, then there must a thinker. So he could doubt the existence of everything EXCEPT himself (since by doubting, he would prove his own existence). From that, he persuaded himself (rather unconvincingly) that the entire world existed.
So to say 'you exist if you think you do' is perfectly Cartesian, provided we interpret it as meaning 'IF you are thinking you exist, then you must exist (thinking is proof of existence)'. What it cannot mean, of course, is that you can think yourself into existence ....
If anyone cares ....
And surely, nothing is forced into *existence*; it is more that the observed particle must assume a determinate position/state if it is observed, whereas its position/state remains indeterminate if not observed (sorry, bit rusty on quantum mechanics).
nick