I don't see why the EPR thought experiment would ever be concieved as a way to demonstrate anything against QM... (you can find an explanation of the EPR thought experiment here: http://en.wikipedia.org/wiki/EPR_paradox) Ok before Alice measures anything P(+z)=0.5 and P(+x)=0.5 for both electrons. Let's say Alice measures the spin in the z diretion and finds it to be +... this means Bob will find his electron's z spin to be - upon measurement, and that P(+x) remains = 0.5 for both electrons. No paradox if we look at it that way right?... Ok well imagine that instead of measuring the z spin of his electron he instead measures the x spin of his electron and finds it to be -ve. The way I think about Heisenberg's uncertainty principle is that he has affected the electron in such a way that he can no longer be certain of its z spin, and P(+z)=0.5 for his electron only, (just as when you measure an electron's z spin then measure x spin, you can no longer be sure of the electron's z spin) while Alice's electron remains in a state of +ve z spin and P(+x)=0.5. As far as I can see there is no problem... Learned views on this would be much appreciated.