On Tue, Aug 14, 2012 at 11:33:48AM +0200, Bruno Marchal wrote:
> >"That which exists" is fundamentally unknowable, and probably not
> >sensible disucssed, hence I prefer to stick with more neutral labels
> >like "syntactic level".
> I disagree with this. With comp we know that the fundamental reality
> is given by *any* Turing complete system. What cannot be discussed
> is which one, but they are all equivalent.
I don't think we're in disagreement here.
> >As for being independent of us, both syntactic and semantic levels are
> >independent of us in the sense that two correspondents must agree on
> >both in order to have a sensible conversation.
> I disagree. Semantics is personal and ill defined, and we don't have
> to agree on the semantics to discuss. We have only to agree with the
> syntactic provability rule. The whole field of logic is based on
> that: the validity of the reasoning are made independent of the
> semantics, which is always subjective and personal.
I am using syntactic layer and semanatic layer as I define them in my
book. Observers do need to agree on these to have a sensible conversation
about complexity and emergence.
I'm not sure if your "semantics" is the same thing at all.
> >I'm not sure that a pseudo-random algorithm would always be good
> >enough, as unless it is cryptographically strong, evolution will make
> >short work of breaking it. If a real random oracle is available, it
> >would be some much easier to use that.
> Technically it can be shown, indeed, that random oracle are richer
> as a resource for problem solving than pseudo randomness, but the
> proof of this are very non constructive, so that it is hard to
> conceive any practical problem for which a random oracle is better.
> I am not sure I see the relation with cryptography.
Cryptographer require that their key generation routines are utterly
unguessable. A cryptographically strong PRNG is one whose sequence is
not easily reverse engineered (in I suppose some NP-hard sense).
> >If you have a coin, then flipping a coin is a good approach. Most
> >brains so not have coins, so I would expect a different mechanism to
> >be used - eg synaptic thermal noise.
> But we don't know in Nature any random process, unless you believe
> in the collapse of the wave packet.
I believe beta decay is truly random, but only believe in subjective
wave function collapse. Beta decay must therefore be a 1p
phenomenon. No particular problem there.
> >>Note that NO machine can ever distinguish a truly random sequence
> >>with some sequence which can be generated by machine more complex
> >>than themselves.
> >That is true. But complex machines are expensive to run.
> But with comp we don't run machine. They all exists and run in
> arithmetic, and the appearances are internal selection. Below the
> subst level we are all confronted with an infinity of unbounded
> complexity (cf the white rabbits).
> >Real random
> >oracles, if available,
> They are available by first person indeterminacy. They are not
> ontologically real, but they are epistemologically real, and this
> plays a big role in the emergence of the physical reality. But I
> doubt it plays a role in our biological evolution. That would mean
> that our substititution level is lower than the quantum one, and I
> don't see any evidence for this.
I don't see that. Evolution will use whatever it can get its hands
on. If it has a source of true random numbers on hand, it will use
that in preference to evolving a cryptographically strong
algorithm. This is for situations where an animal must outsmart
another (eg predator, rival from same species, etc).
In the case of solving NP-hard problems, randomness is useful, but its
harder to see that cryptographic strength is needed. Nevertheless, I
suspect that evolution will favour the use of real random oracles
rather than evolving PRNG algorithms.
>>>>but which is not the non-compatibilist kind of randomness that some
> >>>>defender of free-will want to introduce.
> >>>I have never met anyone wanting to do this. They sound like
> >>>some sort
> >>>of long-discredited Cartesian dualist. Are you sure they're not
> >>>you have conjured up?
> >>John Clark seems to believe that they still exist, as he argues all
> >>the times against them, and then it seems to me that Craig Weinberg
> >>has defended such notion, I think.
> >>I don't think I have conjured up :)
> >John Clark argues against anyone who utters the words "free will". I
> >don't think he particularly targets the "spirit free will theorists"
> >(as Brent calls them).
> But he agrees and even proposes a compatibilist definition.
I'll let him speak to that, but its not the impression I get.
> >No, but it does need 1-randomness
> Imagine the iterated WM-duplication. Why would the resulting peoples
> have more free will than the same person not doing the experience?
> It seems to me that if a decision relies on a perfect coin, it is
> less "free" than if it relies on my partial self-indetermination,
> which itself is a deterministic process, although I cannot see it.
Assuming the coin is operating inside the agent's body? Why would that
be considered non-free?
Prof Russell Standish Phone 0425 253119 (mobile)
Principal, High Performance Coders
Visiting Professor of Mathematics hpco...@hpcoders.com.au
University of New South Wales http://www.hpcoders.com.au
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