[Avodah] Free Will vs. Physics

[Yitzhak Grossman]

On Thu, 25 Sep 2008 17:42:58 -0400
Micha Berger <micha at aishdas.org> wrote:

...

> The first problem is just defining Free Will. What is something that is
> neither deterministic, reducing people to robots, and not random like
> a set of dice? We're claiming some middle ground. RMKoppel proves that
> there are things that are neither describable in algorithms nor random,
> but what kind of such "middle ground" do we mean in this case? Can we
> narrow it down enough to know what it is we're trying to prove?

...

I think that you are conflating the concepts of 'algorithmic' and
'deterministic'.  Something can be noncomputable but perfectly
deterministic, as Turing showed.  Consider a hypothetical universe
whose laws of 'physics' imply that all 'events' are specified by the
outcome of arbitrary (in the sense of unconstrained, not in the sense
of random) Turing machines.  Such a universe would be absolutely
deterministic, but noncomputable, as a consequence of Turing's having
shown the Halting Problem to be noncomputable.

http://en.wikipedia.org/wiki/Halting_problem

N.B. For anyone actually interested in these topics, I highly recommend
Roger Penrose's "The Emperor's New Mind".  I am aware that his views
are quite iconoclastic, but he is a world class mathematician and
physicist, and it's a wonderful and (relatively) accessible discussion
of these and many other related fascinating topics.  He tries to argue,
based on Godel's Incompleteness Theorems, that human intelligence must
involve some sort of noncomputable physics, and he attempts to suggest,
there and in his subsequent books, what that might be.  Again, I am
aware that his work is speculative and controversial, but he is
wonderfully lucid and honest, and he clearly distinguishes between
accepted science and speculation, between consensus and his personal
views and conjectures.  He is also candid and charming, and he strikes
an excellent balance between faithfulness to the math and physics on
the one hand (at least as far as I, an untrained layman, can tell), and
accessibility on the other, and he lacks the arrogance or defensiveness
of some scientists that can be so off putting.

> Micha Berger             "Man wants to achieve greatness overnight, micha at aishdas.org        and he wants to sleep well that night too."

Yitzhak
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