I think this boils down to the issue: what does 'free will' mean? If somebody knows exactly what you're going to do, does that mean you aren't free to do it? I mean, you're doing it by your own free will, but somebody knows you will, but does that make the action any less free? Somebody posted something from Minority Report, which asks that same question.
When I talk about free will, I am implying that at any given moment, an individual is able to choose an action. That is to say, there could be many possible actions that can occurr, even if one of those actions is most likely to occurr. While some things can be known (without reasonable doubt) in advance, that doesn't necessarily invalidate any other possible outcome. Suppose someone throws a punch at you, one could say that you are most likely to dodge the punch, but that doesn't necessarily rule out the possibility that you don't dodge. So no, it doesn't make it any less free.
My deal with predestination is that there is only one possible outcome at any given moment. But I want to note something that is counter-intuitive, a fallacy I made on the vL forums once upon a time.
Just because there is only one possible outcome at every moment,
doesn't necessarily mean the outcome can be predicted in advance.
An example can be shown with a very simple discrete time dynamical system:
x
n+1=ax
n(1-x
n)
This is a very simple recursion of the logistic map. The variable 'a' is whats known as a bifurcation variable.
Now, if a > 3.57, the iterates (the terms generated by the recursion) experience a mathematical behavior known as chaos (well, there are strange windows after a > 3.57 where the iteration becomes periodic again).
Now, I claim to you, that even given x
0, the iterates are unpredictable after a certain point. When I say "unpredictable", I mean the impossibility to know for certain future iterates without using the recurssion. If you used the recurrsion to predict a future iteration, say x
10000, then that'd be like predicting the weather for Thursday, by
waiting until Thursday.
Now, the scary aspect of chaos, is that its
predetermined. So, in the case of a predestined universe, it's possible to lack the ability to predict.
So I emphasize, the difference between a non-determistic system and a deterministic system is only the presence of probability. While some things can be known, without reasonable doubt, to occurr in advance, this does not invalidate other possible outcomes for a given moment. Whereas, in the case of a deterministic system, while something can be unpredictable, there is only but one possible outcome at every given moment.
Now, I leave you with this question:
If we could rewind a day ... would the day happen exactly the same way?
See also:
http://mathworld.wolfram.com/Bifurcation.htmlhttp://mathworld.wolfram.com/Chaos.html