I'm dealing with these questions in an artificial life system - Tierra
to be precise. I have compared the original Tierra code, with one in
which the random no. generator is replaced with a true random
no. generator called HAVEGE, and another simulation in which the RNG
is replaced with a cryptographically secure RNG called ISAAC. The
results to date (and this _is_ work in progress) is that there is a
distinct difference between the original Tierra PRNG, and the other
two generators, but that there is little difference between HAVEGE and
ISAAC. This seems to indicate that algorithmic randomness can be good
enough to fool learning algorithms.
That's a very interesting experiment -- you might be interested to know that Dennett (again, in Elbow Room) predicted something similar; that for all the cases where randomness impacts an organism's choices, "true" randomness would be practically indistinguishable from sufficiently unpredictable pseudorandomness. I'm glad you're doing these experiments. How does your true random number generator work? Do you have preliminary results posted somewhere?
Anyway, I think that the important question of free will is not "Could I have done otherwise than I did in >this exact circumstance<", but this:
"Am I so constituted that I will act the way I did in circumstances >relevantly like this<, but will be able to change my behavior in the way I want to when circumstances change?".
In other words -- we really don't care whether or not we'd do the same thing over and over again if circumstances were exactly the same. That kind of "free will", what you would get from indeterminism, is not at all what people care about when they think about whether they have free will or not. What we care about is whether we have self-control.
The whole debate you quote from Dennett seems quaint and out of date..., but I think it's very useful (and actually it was from the Stanford encyclopedia of philosophy, not from Dennett). There's been a lot of definitional hair-splitting here about just what free will is and isn't; I propose to approach the question in a different way: What do you personally care about? Does it matter to you whether the universe is deterministic or not? Would it matter to you if you realized someone was using subliminal advertising on you to make you buy things? (I'm not suggesting that what we want to be the case has any influence on what is the case; I'm just trying to get at what people mean when they say "free will".)
Well, it looks like there are as many definitions of free will as there are people taking part in the debate -- which is precisely why we need to talk about it, and why it's a good idea be familiar with at least the high points of the past 2500 years of philosophical literature on the subject, in order to avoid making the same mistakes that other brilliant minds have made.