Physical limits of inference – Theories of almost everything?
There is a review at Nature’s News and Views section by P.-M. Binder about a recent article by David H. Wolpert from NASA Ames Research Center, entitled “Physical limits of inference“. Binder writes:
A provocative contribution to the logic of science extends the theorems of Kurt Gödel and Alan Turing, and bears on thinking about prediction, the standard model of particles, and quantum gravity.
From the abstract of the paper, one reads
We show that physical devices that perform observation, prediction, or recollection share an underlying mathematical structure. We call devices with that structure “inference devices”. We present a set of existence and impossibility results concerning inference devices. These results hold independent of the precise physical laws governing our universe. In a limited sense, the impossibility results establish that Laplace was wrong to claim that even in a classical, non-chaotic universe the future can be unerringly predicted, given sufficient knowledge of the present. Alternatively, these impossibility results can be viewed as a non-quantum-mechanical “uncertainty principle”.
[Yeah, Laplace was wrong even classically, according to my SF novel... 
]
and
(…) We informally discuss the philosophical implications of these results, e.g., for whether the universe “is” a computer.
I find it very surprising that this was published in Physica D: Nonlinear Phenomena, and not in a philosophical journal. I have no criticisms against this work in particular (I did not read the paper in full), it is just that it does not seem, from a first impression, a physics paper per se, as much as interesting as it may seem.
Another (somewhat funny, I must admit, but it may be a reflection of my present pessimistic/sarcastic mood) excerpt from Binder’s review is this:
The other limitation is our inability to bring quantum mechanics and gravity into a single theory, although several viable alternative theories are being studied [9]. Quantum electrodynamics, a refinement of quantum mechanics, is defined by just two parameters (the charge and mass of the electron), whereas quantum gravity would require infinitely many parameters, and hence infinite experiments to determine those parameters, making it so far a meaningless theory.
BTW, Ref. [9] above is Wilczek’s book, The Lightness of Being.
October 17, 2008 at 11:16 am
“I find it very surprising that this was published in Physica D: Nonlinear Phenomena, and not in a philosophical journal. I have no criticisms against this work in particular (I did not read the paper in full), it is just that it does not seem, from a first impression, a physics paper per se, as much as interesting as it may seem.”
The paper is mathematical, rather than philosophical, but with a kind of math that has nothing to do with physical reality it pretends to describe (that’s why conclusions look so close to philosophy). However, it just explains very well why it is readily published in a physical journal: these ones are totally dominated by that kind of “mathematical physics” that should be as far away from reality as possible. By contrast, it is very difficult to publish anything using mathematics only as a tool for description of a physically real system dynamics, with the emphasis on the latter. Because according to the dominating mainstream doctrine (reduced to an irrational belief) we are living in a “mathematical (Platonic) universe”, with its physical envelope being only a misleading illusion that hides the “true”, “purely mathematical” basis of reality. Did you know it? What would be the reaction of your sarcastic mood to it? Welcome to reality, our totally abstract reality…
No, they don’t need the truth, they just need unconditional support for their mathematical exercises, with their own criteria of validity having nothing to do with “physics” in a common-sense meaning (and still it’s called “physics” and actively expels any remaining common-sense, problem-solving physical research).
With such “reality”, it’s much better to jump to science fiction realms, you’re right. To raise our mood, why not to start developing/discussing here your sci-fi results?
P.S. Another example: following your recent advice, I looked through the last Perimeter Institute conference on the problem of time and found, of course, no time problem solution but again only that fruitless math-physical “philosophy”… What is the sense to propose them a causally complete solution of real physical time problem (e.g. http://arxiv.org/abs/physics/0601140)? It’s much better to take a time machine from your fantasies and make a leap to another reality, where physics is always dominated by “ordinary” logic/consistency and common sense!
October 17, 2008 at 6:00 pm
Hi Andrei,
You can do philosophy with mathematics, e.g., analytical philosophy.
There are many things that I do not agree concerning some present “scientific” practices (not the case specifically with Wolpert’s paper at the moment, since I did not study it in detail), so in some level, I sympathize with your disgust for the current state of affairs, but generally, I must say that I am not aligned with the specific way that you see the problem or expose it. I see that you have a homepage — perhaps it is time for you to consider running a blog, a nice tool to expose your point of view and receive feedbacks.
Christine
October 18, 2008 at 12:23 pm
“perhaps it is time for you to consider running a blog, a nice tool to expose your point of view and receive feedbacks”
To obtain what as a result, just an “exchange of opinions”, a possibility to “chat”, without any progress? That’s too little in my case. Can my results, consistent problem solutions I propose obtain any essential support in that way? It’s generally good, of course, to have all those possibilities of instant world-wide communication, blogs and the rest, but let’s not over-estimate their influence either. It’s just a modern version of that eternal injustice in human world: real (material) possibilities for ones, cheap nonmaterial possibility to only “talk” for others. OK, now it’s global, we can talk at any distance and across borders, but it means only that the unconditional, ever persisting injustice becomes global. It’s interesting that in science it’s even much greater than in other, more practical and less “intellectual” fields of activity. My materials, in particular, are easily accessible (and discussed) in the internet, as well as at real-world meetings, already for many years, and their results completing successfully the efforts of such great thinkers as Louis de Broglie and providing explicit solutions to otherwise painfully stagnating problems have never shown any sign of essential weakness or basic error. They are just unconditionally ignored by science-support establishments, while others, providing no solution at all and only multiplying problems, are unconditionally supported (without even being understood by any public larger than few interested persons), and it does not depend on any missing information or internet discussion possibility. Simply such is this world, its best, “intellectual” part, and I am not alone with such experience and conclusion…
I don’t know why you and some other bloggers are so attentive to a place of discussion, “your blog”, “my blog”… The whole meaning of this interaction is that it is open to everybody and happens in the internet, doesn’t matter on whose blog in this or that moment. If everybody creates a blog a tries to gather there his small “company of friends” exchanging meaningless compliments (this is already the case in many segments of the blogosphere), then it’s just an e-world reproduction of the old good separation and segregation in the real world. What could make a difference and therefore be of greater interest is an intense interaction across all disciplines and small subjective preferences, for which one would need a smaller number of places, doesn’t matter whom they formally “belong” to. If everybody remains forever with their preferences and subjective interests, then nothing ever changes, while a big change would indeed be necessary “dans le monde endormi”.
Anyway, I hope that at least you continue your communication efforts here and would still try to include your wider, sci-fi dimensions. You’re urging me, I am urging you, and … nothing changes. That’s how it goes, our world-wide communication
.
October 18, 2008 at 2:46 pm
Dear Andrei,
Actually, I expect nothing of blogs, including this one (my own). It may appear to some people that blogs are everything in their lives (actually, some people live much more in the virtual world than in real world). But it is not my case, really. I have already run and deleted a previous blog, and I may just find myself in a position to do it again, if I like, and someday I may simply disapear from the internet (well, maybe not entirely, since the internet “never forgets”…). So it’s not a big deal, you know. Anyway. My suggestion for you to run a blog is because it appears that you strive for communicating your ideas and points of view, but I may be mistaken, and maybe your homepage already offers everything that you would like to say and contribute. In any case, I really do not understand you entirely, and I believe this isn’t really the place (or time) to do it.
Good luck,
Christine