: I submit that processes can be effectively (for human
: purposes, and who else is science for?) random from a
: certain perspective and yet deterministic from
: another. A similar example is the way certain
: computers generate random numbers, by grabbing a few
: digits off of an operation it happens to be performing
: at the moment. Truly random? No, but effectively so.
This is the "hidden variable" hypothesis Einstein suggested to explain apparently indeterminate processes in QM: that something is in fact determining those processes' outcomes, but we haven't yet seen it and perhaps we can't see it.
After all, even if dice were completely and hopelessly beyond our power to analyze, we could still list a die's value each time it's thrown: 1,2,5,1,3,5,6,3,2,5,6,1,4,5,6... So if you wrote down a list of random numbers beforehand and were lucky enough to reproduce the correct list, you'd have a perfectly correct theory of what values turn up on that die when. The process would be determinist, even if we couldn't possibly think up the correct theory to describe it without a huge helping of luck.
And this is where Bell's theorem comes in. It shows that for a given process--the "entangled particles" experiment is one common variant--you'd see certain inequalities in the outcome data provided the process was locally determinist in *any* way...even the minimal "you can write down a list of outcomes" way. QM's predictions do not show these inequalities...and neither, apparently, does the data gathered by experiment. Reality is not even second-hand locally determinate.
Now Bell's theorem doesn't apply to non-local determinism...that is, it still allows for you to be able to predict the outcome of an experiment *provided* you know everything else about the universe at every place and time. So we can't be sure whether the "real world" is truly indeterminate, or simply non-locally determinate. But as finite beings ourselves, we can never be sure of this anyway.
--SiliconDream
