Ben,
I am not sure if you are aware (or just ignoring) that strings and loops aren't the only approaches to quantum gravity. There is also a discrete approach based on causal sets where quantification is done from the start, at the level of spacetime. The approach is aimed at the unification of Physics. They are basically trying to trace causality in full detail from spacetime up and through quantum mechanics and relativity. They equate causality with time. I find their thinking quite akin with mine. In fact, interpreting my functional as physical action, macroscopic Physics enters the picture. The principle of symmetry (symmetry gives rise to conservation laws), and the principle of least action (trajectory of a conservative system), are both accounted for. I discussed these ideas at an APS meeting, got many interesting questions (unlike AGI...). Many physicists believe that quantum theory contains fundamental flaws. In particular regarding the role of the observer. Its founders went to a great extent to provide an objective foundation, but in the process made a great mess about the observer, the collapse of the wave function when an observation is made. They were even forced to say that QM can not be understood. But we are not locked in such a situation for ever. Efforts are on their way to free us from it. The situation is that QM is a correct theory, it works, and it alloes us to calculate things that we measure. But the interpretation of why it works is not yet understood. Facts are, physical systems do binding, associations and structures, people do binding, associations and structures, emergent inference does binding, associations and structures, Turing computation is not known for doing binding, associations or structures. Physical systems include the brain. Brains are very good at making algorithms, but not at using them. That's why we need Turing computers. Sergio From: Ben Goertzel [mailto:[email protected]] Sent: Tuesday, July 10, 2012 9:06 AM To: AGI Subject: Re: [agi] Analog Computation This is ground that has been well-trodden in the recent literature on hypercomputation. Mathematically, yes, analog computers (and analog neural nets) can in principle do hyper-Turing computation Quantum physics appears to rule out this kind of analog computing existing in reality, but general relativity would permit it... and as you know these theories have not yet been unified. String theory and loop quantum gravity would also, according to my best understanding, not permit it... Since the totality of scientific data consists of a large finite set of finite-precision numbers, there is no possible way for science (as presently conceived) to validate or refute the hypothesis that hyper-Turing computers (of the analog or other variety) exist physically. In this sense, the hypothesis of trans-Turing computing in the brain or any other physical system is non-scientific. -- Ben G On Tue, Jul 10, 2012 at 8:57 PM, Sergio Pissanetzky <[email protected]> wrote: Ben, You asked recently for comments on analog computation (I forgot what thread that was, so I started a new one). My comment is on the need for a comparison between Turing computation and analog computation. Of course, AC can do all that TC can do, but can it do more? I believe it can. TC is particularly weak in everything related to binding, associations, and the resulting structures (BAS). Anywhere that BAS are needed, humans are called for help. Have you noticed? It never fails. I have compiled a list of problems that are "easy for humans but very difficult for computers to solve", the GUAPS, great unsolved automation problems of software engineering. They all critically depend on BAS. They include OO analysis and design, object recognition, self-programming, and many others. Turing himself was concerned about this limitation, and he wrote extensively about it in the context of morphogenesis but never solved the problem. The GUAPs, of course, include the invariant structures that our brains make (I know a chair is a chair even if it is upside down => invariance under transformations). It seems to me that AC can do more than TC. Because physical systems do self-organize and make structures. Physics even has theorems about this. If so, AGI would be squarely outside the domain of TC, and strictly within that part of the domain of AC that is not TC. Sergio AGI | <https://www.listbox.com/member/archive/303/=now> Archives <https://www.listbox.com/member/archive/rss/303/18883996-f0d58d57> | Modify Your Subscription <https://www.listbox.com/member/archive/rss/303/18883996-f0d58d57> <https://www.listbox.com/member/archive/rss/303/18883996-f0d58d57> <https://www.listbox.com/member/archive/rss/303/18883996-f0d58d57> AGI | Archives | Modify Your Subscription <https://www.listbox.com/member/archive/rss/303/18883996-f0d58d57> <https://www.listbox.com/member/archive/rss/303/18883996-f0d58d57> -- Ben Goertzel, PhD http://goertzel.org "My humanity is a constant self-overcoming" -- Friedrich Nietzsche <https://www.listbox.com/member/archive/rss/303/18883996-f0d58d57> AGI | Archives | Modify Your Subscription <https://www.listbox.com/member/archive/rss/303/18883996-f0d58d57> <https://www.listbox.com/member/archive/rss/303/18883996-f0d58d57> ------------------------------------------- AGI Archives: https://www.listbox.com/member/archive/303/=now RSS Feed: https://www.listbox.com/member/archive/rss/303/21088071-c97d2393 Modify Your Subscription: https://www.listbox.com/member/?member_id=21088071&id_secret=21088071-2484a968 Powered by Listbox: http://www.listbox.com
