Digital physics: Difference between revisions
Extended confirmed users 9,178 edits →Wheeler's "it from bit": Remove problematic sentence that is essentially redundant with those that follow in this paragraph. |
→History: Removed unnecessary review link |
||
Line 4: | Line 4: | ||
The operations of [[computer]]s must be compatible with the principles of [[information theory]], [[statistical thermodynamics]], and [[quantum mechanics]]. In 1957, a link among these fields was proposed by [[Edwin Jaynes]].<ref>{{cite journal | last=Jaynes | first=E. T. | title=Information Theory and Statistical Mechanics | journal=Physical Review | publisher=American Physical Society (APS) | volume=106 | issue=4 | date=1957-05-15 | issn=0031-899X | doi=10.1103/physrev.106.620 | pages=620–630|url=http://bayes.wustl.edu/etj/articles/theory.1.pdf}} <br>{{cite journal | last=Jaynes | first=E. T. | title=Information Theory and Statistical Mechanics. II | journal=Physical Review | publisher=American Physical Society (APS) | volume=108 | issue=2 | date=1957-10-15 | issn=0031-899X | doi=10.1103/physrev.108.171 | pages=171–190|url=http://bayes.wustl.edu/etj/articles/theory.2.pdf}}</ref> He elaborated an interpretation of [[probability theory]] as generalized [[Aristotelian logic]], a view linking fundamental physics with [[digital computers]], because these are designed to implement the [[logical operations|operations]] of [[classical logic]] and, equivalently, of [[Boolean algebra (logic)|Boolean algebra]].<ref>Jaynes, E. T., 1990, "[http://bayes.wustl.edu/etj/articles/prob.as.logic.pdf Probability Theory as Logic,]" in Fougere, P.F., ed., ''Maximum-Entropy and Bayesian Methods''. Boston: Kluwer.</ref> |
The operations of [[computer]]s must be compatible with the principles of [[information theory]], [[statistical thermodynamics]], and [[quantum mechanics]]. In 1957, a link among these fields was proposed by [[Edwin Jaynes]].<ref>{{cite journal | last=Jaynes | first=E. T. | title=Information Theory and Statistical Mechanics | journal=Physical Review | publisher=American Physical Society (APS) | volume=106 | issue=4 | date=1957-05-15 | issn=0031-899X | doi=10.1103/physrev.106.620 | pages=620–630|url=http://bayes.wustl.edu/etj/articles/theory.1.pdf}} <br>{{cite journal | last=Jaynes | first=E. T. | title=Information Theory and Statistical Mechanics. II | journal=Physical Review | publisher=American Physical Society (APS) | volume=108 | issue=2 | date=1957-10-15 | issn=0031-899X | doi=10.1103/physrev.108.171 | pages=171–190|url=http://bayes.wustl.edu/etj/articles/theory.2.pdf}}</ref> He elaborated an interpretation of [[probability theory]] as generalized [[Aristotelian logic]], a view linking fundamental physics with [[digital computers]], because these are designed to implement the [[logical operations|operations]] of [[classical logic]] and, equivalently, of [[Boolean algebra (logic)|Boolean algebra]].<ref>Jaynes, E. T., 1990, "[http://bayes.wustl.edu/etj/articles/prob.as.logic.pdf Probability Theory as Logic,]" in Fougere, P.F., ed., ''Maximum-Entropy and Bayesian Methods''. Boston: Kluwer.</ref> |
||
The hypothesis that the [[universe]] is a [[digital computer]] was proposed by [[Konrad Zuse]] in his book ''Rechnender Raum'' (translated into English as ''[[Calculating Space]]''). The term ''digital physics'' was{{citation needed|date=June 2016}} employed by [[Edward Fredkin]], who later came to prefer the term ''[[digital philosophy]]''.<ref>See Fredkin's [http://www.digitalphilosophy.org Digital Philosophy web site.]</ref> Others who have modeled the universe as a giant computer include [[Stephen Wolfram]],<ref>''[[A New Kind of Science]]'' [http://www.wolframscience.com website |
The hypothesis that the [[universe]] is a [[digital computer]] was proposed by [[Konrad Zuse]] in his book ''Rechnender Raum'' (translated into English as ''[[Calculating Space]]''). The term ''digital physics'' was{{citation needed|date=June 2016}} employed by [[Edward Fredkin]], who later came to prefer the term ''[[digital philosophy]]''.<ref>See Fredkin's [http://www.digitalphilosophy.org Digital Philosophy web site.]</ref> Others who have modeled the universe as a giant computer include [[Stephen Wolfram]],<ref>''[[A New Kind of Science]]'' [http://www.wolframscience.com website.]</ref> [[Juergen Schmidhuber]],<ref name="Schmidhuber, J.,">Schmidhuber, J., "[http://www.idsia.ch/~juergen/computeruniverse.html Computer Universes and an Algorithmic Theory of Everything]"; [ftp://ftp.idsia.ch/pub/juergen/everything.pdf A Computer Scientist's View of Life, the Universe, and Everything].</ref> and Nobel laureate [[Gerard 't Hooft]].<ref>{{cite journal | last=Hooft | first=Gerard 't | title=Quantum gravity as a dissipative deterministic system | journal=Classical and Quantum Gravity | publisher=IOP Publishing | volume=16 | issue=10 | date=1999-09-07 | issn=0264-9381 | doi=10.1088/0264-9381/16/10/316 | pages=3263–3279|arxiv=gr-qc/9903084}}</ref> These authors hold that the [[probabilistic]] nature of [[quantum physics]] is not necessarily incompatible with the notion of computability. Quantum versions of digital physics have recently been proposed by [[Seth Lloyd]]<ref>Lloyd, S., "[https://arxiv.org/abs/quant-ph/0501135 The Computational Universe: Quantum gravity from quantum computation.]"</ref>, [[Paola Zizzi]]<ref>Zizzi, Paola, "[https://arxiv.org/abs/gr-qc/0304032 Spacetime at the Planck Scale: The Quantum Computer View.]"</ref>, and [[Antonio Sciarretta]].<ref>{{cite journal | last=Sciarretta | first=Antonio | title=A Local-Realistic Model of Quantum Mechanics Based on a Discrete Spacetime | journal=Foundations of Physics | publisher=Springer Science and Business Media LLC | volume=48 | issue=1 | date=2017-12-13 | issn=0015-9018 | doi=10.1007/s10701-017-0129-9 | pages=60–91}}</ref> |
||
Related ideas include [[Carl Friedrich von Weizsäcker]]'s binary theory of ur-alternatives, pancomputationalism, computational universe theory, [[John Archibald Wheeler]]'s "It from bit", and [[Max Tegmark]]'s [[ultimate ensemble]]. |
Related ideas include [[Carl Friedrich von Weizsäcker]]'s binary theory of ur-alternatives, pancomputationalism, computational universe theory, [[John Archibald Wheeler]]'s "It from bit", and [[Max Tegmark]]'s [[ultimate ensemble]]. |
Revision as of 10:03, 25 February 2020
In
History
The operations of
The hypothesis that the
Related ideas include
Overview
Digital physics suggests that there exists, at least in principle, a
Loop quantum gravity could lend support to digital physics, in that it assumes space-time is quantized.[1] Paola Zizzi has formulated a realization of this concept in what has come to be called "computational loop quantum gravity", or CLQG.[11][12] Other theories that combine aspects of digital physics with loop quantum gravity are those of Marzuoli and Rasetti[13][14] and Girelli and Livine.[15]
Weizsäcker's ur-alternatives
Physicist
Pancomputationalism
Pancomputationalism (also known as naturalist computationalism)[22] is a view that the universe is a computational machine, or rather a network of computational processes that, following fundamental physical laws, computes (dynamically develops) its own next state from the current one.[23]
A computational universe is proposed by Jürgen Schmidhuber in a paper based on Zuse's 1967 thesis[24]. He pointed out that a simple explanation of the universe would be a Turing machine programmed to execute all possible programs computing all possible histories for all types of computable physical laws. He also pointed out that there is an optimally efficient way of computing all computable universes based on Leonid Levin's universal search algorithm (published in 1973)[25]. In 2000, he expanded this work by combining Ray Solomonoff's theory of inductive inference with the assumption that quickly computable universes are more likely than others. This work on digital physics also led to limit-computable generalizations of algorithmic information or Kolmogorov complexity and the concept of Super Omegas, which are limit-computable numbers that are even more random (in a certain sense) than Gregory Chaitin's number of wisdom Omega.
Wheeler's "it from bit"
Following Jaynes and Weizsäcker, the physicist
In a 1986 eulogy to the mathematician Hermann Weyl, Wheeler proclaimed: "Time, among all concepts in the world of physics, puts up the greatest resistance to being dethroned from ideal continuum to the world of the discrete, of information, of bits. ... Of all obstacles to a thoroughly penetrating account of existence, none looms up more dismayingly than 'time.' Explain time? Not without explaining existence. Explain existence? Not without explaining time. To uncover the deep and hidden connection between time and existence ... is a task for the future."[29][30][31]
Digital vs. informational physics
Not every informational approach to physics (or
Pancomputationalists like Lloyd (2006), who models the universe as a
Computational foundations
Turing machines
The Church–Turing–Deutsch thesis
The classic Church–Turing thesis claims that any computer as powerful as a Turing machine can, in principle, calculate anything that a human can calculate, given enough time. Turing moreover showed that there exist universal Turing machines that can compute anything any other Turing machine can compute—that they are generalizable Turing machines. But the limits of practical computation are set by physics, not by theoretical computer science:
"Turing did not show that his machines can solve any problem that can be solved 'by instructions, explicitly stated rules, or procedures', nor did he prove that the universal Turing machine 'can compute any function that any computer, with any architecture, can compute'. He proved that his universal machine can compute any function that any Turing machine can compute; and he put forward, and advanced philosophical arguments in support of, the thesis here called Turing's thesis. But a thesis concerning the extent of effective methods—which is to say, concerning the extent of procedures of a certain sort that a human being unaided by machinery is capable of carrying out—carries no implication concerning the extent of the procedures that machines are capable of carrying out, even machines acting in accordance with 'explicitly stated rules.' For among a machine's repertoire of atomic operations there may be those that no human being unaided by machinery can perform."[34]
On the other hand, a modification of Turing's assumptions does bring practical computation within Turing's limits; as David Deutsch puts it:
"I can now state the physical version of the Church–Turing principle: 'Every finitely realizable physical system can be perfectly simulated by a universal model computing machine operating by finite means.' This formulation is both better defined and more physical than Turing's own way of expressing it."[35] (Emphasis added)
This compound conjecture is sometimes called the "strong Church–Turing thesis" or the Church–Turing–Deutsch principle. It is stronger because a human or Turing machine computing with pencil and paper (under Turing's conditions) is a finitely realizable physical system.
Experimental confirmation
So far there is no experimental confirmation of either binary or quantized nature of the universe, which are basic for digital physics. The few attempts made in this direction would include the experiment with holometer designed by Craig Hogan, which among others would detect a bit structure of space-time.[36] The experiment started collecting data in August 2014.
A new result of the experiment released on December 3, 2015, after a year of data collection, has ruled out Hogan's theory of a pixelated universe to a high degree of
Criticism
Physical symmetries are continuous
One objection is that extant models of digital physics are incompatible [
Proponents of digital physics claim that such continuous symmetries are only convenient (and very good) approximations of a discrete reality. For example, the reasoning leading to systems of
Moreover, computers can manipulate and solve formulas describing real numbers using
A number—in particular a
"So ordinary computational descriptions do not have a cardinality of states and state space trajectories that is sufficient for them to map onto ordinary mathematical descriptions of natural systems. Thus, from the point of view of strict mathematical description, the thesis that everything is a computing system in this second sense cannot be supported".[39]
For his part,
Locality
Some argue that extant models of digital physics violate various postulates of
See also
|
|
|
References
- ^ a b c d e Schmidhuber, J., "Computer Universes and an Algorithmic Theory of Everything"; A Computer Scientist's View of Life, the Universe, and Everything.
- ISSN 0031-899X.
- ^ Jaynes, E. T., 1990, "Probability Theory as Logic," in Fougere, P.F., ed., Maximum-Entropy and Bayesian Methods. Boston: Kluwer.
- ^ See Fredkin's Digital Philosophy web site.
- ^ A New Kind of Science website.
- ISSN 0264-9381.
- ^ Lloyd, S., "The Computational Universe: Quantum gravity from quantum computation."
- ^ Zizzi, Paola, "Spacetime at the Planck Scale: The Quantum Computer View."
- ISSN 0015-9018.
- ^ Zuse, Konrad, 1967, Elektronische Datenverarbeitung vol 8., pages 336–344
- ISSN 0217-7323.
- ^ Zizzi, Paola, "Computability at the Planck Scale."
- ISSN 0375-9601.
- ISSN 0003-4916.
- ISSN 0264-9381.
- ISBN 978-3-446-11479-1.
- ^ von Weizsäcker, Carl Friedrich (1980). The Unity of Nature. New York: Farrar, Straus, and Giroux.
{{cite book}}
: CS1 maint: location missing publisher (link) - ISBN 978-3-446-14142-1.)
{{cite book}}
: CS1 maint: location missing publisher (link - ISBN 978-1-4020-5234-7.
- ^ von Weizsäcker, Carl Friedrich (1992). Zeit und Wissen (in German).
- .
- ^ Gordana Dodig-Crnkovic, "Info‐Computational Philosophy Of Nature: An Informational Universe With Computational Dynamics" (2011).
- ^ Papers on pancomputationalism on philpapers.org
- ^ Zuse's Thesis
- ^ Levin, Leonid (1973). "Universal search problems (Russian: Универсальные задачи перебора, Universal'nye perebornye zadachi)". Problems of Information Transmission (Russian: Проблемы передачи информации, Problemy Peredachi Informatsii). 9 (3): 115–116. (pdf)
- ISBN 0-393-04642-7.
- ISBN 9780201515091. OCLC 21482771
- ^ Chalmers, David. J., 1995, "Facing up to the Hard Problem of Consciousness", Journal of Consciousness Studies 2(3): 200–19. This paper cites John A. Wheeler (1990) op. cit. Also see Chalmers, D., 1996. The Conscious Mind. Oxford University Press.
- ^ Wheeler, John Archibald, 1986, "Hermann Weyl and the Unity of Knowledge", American Scientist, 74: 366-375.
- ^ Eldred, Michael, 2009, 'Postscript 2: On quantum physics' assault on time'
- ISBN 978-3-86838-045-3
- ^ Floridi, L., 2004, "Informational Realism, Archived 2012-02-07 at the Wayback Machine" in Weckert, J., and Al-Saggaf, Y, eds., Computing and Philosophy Conference, vol. 37."
- ^ See Floridi talk on Informational Nature of Reality, abstract at the E-CAP conference 2006.
- B. Jack Copeland.
- ^ David Deutsch, "Quantum Theory, the Church–Turing Principle and the Universal Quantum Computer."
- ^ Andre Salles, "Do we live in a 2-D hologram? New Fermilab experiment will test the nature of the universe", Fermilab Office of Communication, August 26, 2014 [1]
- ^ "Holometer rules out first theory of space-time correlations | News". news.fnal.gov. Retrieved 2018-10-19.
- John A. Wheeler, 1990, "Information, physics, quantum: The search for links" in W. Zurek (ed.) Complexity, Entropy, and the Physics of Information. Redwood City, CA: Addison-Wesley.
- ISSN 0004-8402.
- arXiv:quant-ph/0206089.
- ISBN 978-3-540-22188-3.
- ISSN 0449-1947.
Further reading
- Paul Davies, 1992. The Mind of God: The Scientific Basis for a Rational World. New York: Simon & Schuster.
- David Deutsch, 1997. The Fabric of Reality. New York: Allan Lane.
- Michael Eldred, 2009, The Digital Cast of Being: Metaphysics, Mathematics, Cartesianism, Cybernetics, Capitalism, Communication ontos, Frankfurt 2009, 137 pp. ISBN 978-3-86838-045-3
- Edward Fredkin, 1990. "Digital Mechanics," Physica D: 254-70.
- Seth Lloyd, Ultimate physical limits to computation, Nature, volume 406, pages 1047–1054
- Mariusz Stanowski, 2014. De Broglie Waves and a Complexity Definition, Infinite Energy, Vol 20, 116 pages 41–45. [2]
- Carl Friedrich von Weizsäcker,1972. "Die Einheit der Natur", München: Hanser; 1980. The Unity of Nature. New York: Farrar Straus & Giroux.
- John Archibald Wheeler, 1990. "Information, physics, quantum: The search for links" in W. Zurek (ed.) Complexity, Entropy, and the Physics of Information. Addison-Wesley.
- ISBN 0-393-04642-7.
- ISBN 0-06-097257-2. This book discusses Edward Fredkin's work.
- Hector Zenil (ed.), 2012. A Computable Universe: Understanding and Exploring Nature As Computation with a Foreword by Sir Roger Penrose. Singapore: World Scientific Publishing Company.
- Rechnender Raum.
External links
- Discrete Physics; Mountain Math Software.
- Luciano Floridi, "Against Digital Ontology", Synthese, 2009, 168.1, (2009), 151–178.
- Edward Fredkin:
- It from bit and fit from bit. On the origin and impact of information in the average evolution (Yves Decadt, 2000). Book published in Dutch with English paper summary in The Information Philosopher, http://www.informationphilosopher.com/solutions/scientists/decadt/
- Gontigno, Paulo, "Hypercomputation and the Physical Church–Turing thesis"
- Juergen Schmidhuber:
- Konrad Zuse, PDF scan of Zuse's paper.
- Konrad Zuse, Re-edition of Zuse's paper in modern LaTeX.
- The Oxford Advanced Seminar on Informatic Structures
- Wired: God is the Machine
- Gualtiero Piccinini. Computation in Physical Systems Discusses the metaphysical foundations of digital physics in section 3.4.