Editing Roger Penrose (section)

=== Consciousness ===
[[File:Roger Penrose 9671.JPG|thumb|Penrose at a conference circa 2011]]
Penrose has written books on the connection between fundamental physics and human (or animal) consciousness. In ''[[The Emperor's New Mind]]'' (1989), he argues that known laws of physics are inadequate to explain the phenomenon of consciousness.<ref>{{Cite news|last=Ferris|first=Timothy|date=19 November 1989|title=HOW THE BRAIN WORKS, MAYBE (Published 1989)|language=en-US|work=[[The New York Times]]| author-link=Timothy Ferris| url=https://www.nytimes.com/1989/11/19/books/how-the-brain-works-maybe.html|access-date=7 October 2020|issn=0362-4331|archive-date=19 November 2021|archive-url=https://web.archive.org/web/20211119091901/https://www.nytimes.com/1989/11/19/books/how-the-brain-works-maybe.html|url-status=live}}</ref> Penrose proposes the characteristics this new physics may have and specifies the requirements for a bridge between classical and quantum mechanics (what he calls ''correct quantum gravity'').<ref>{{Cite web|last=Stork|first=David G.|date=29 October 1989|title=The Physicist Against the Hackers : THE EMPEROR'S NEW MIND: On Computers, Minds, and the Laws of Physics by Roger Penrose (Oxford University Press: $24.95; 428 pp.)|url=https://www.latimes.com/archives/la-xpm-1989-10-29-bk-90-story.html|access-date=7 October 2020|website=Los Angeles Times|language=en-US|archive-date=7 December 2021|archive-url=https://web.archive.org/web/20211207185551/https://www.latimes.com/archives/la-xpm-1989-10-29-bk-90-story.html|url-status=live}}</ref> Penrose uses a variant of [[Turing's halting theorem]] to demonstrate that a system can be [[deterministic]] without being [[algorithm]]ic. (For example, imagine a system with only two states, ON and OFF. If the system's state is ON when a given [[Turing machine]] halts and OFF when the Turing machine does not halt, then the system's state is completely determined by the machine; nevertheless, there is no algorithmic way to determine whether the Turing machine stops.)<ref>{{Cite book|last=Penrose|first=Roger|url=https://books.google.com/books?id=JF4vDwAAQBAJ&q=turing+halting|title=The Emperor's New Mind: Concerning Computers, Minds, and the Laws of Physics|date=28 April 2016|publisher=Oxford University Press|isbn=978-0-19-255007-1|language=en|access-date=12 October 2020|archive-date=7 December 2021|archive-url=https://web.archive.org/web/20211207185551/https://books.google.com/books?id=JF4vDwAAQBAJ&q=turing+halting|url-status=live}}</ref><ref>{{Cite web|title=20th WCP: Computational Complexity and Philosophical Dualism|url=https://www.bu.edu/wcp/Papers/Cogn/CognTeix.htm|access-date=7 October 2020|website=www.bu.edu|archive-date=13 October 2020|archive-url=https://web.archive.org/web/20201013092220/https://www.bu.edu/wcp/Papers/Cogn/CognTeix.htm|url-status=live}}</ref>

Penrose believes that such deterministic yet non-algorithmic processes may come into play in the quantum mechanical [[Wave function collapse|wave function reduction]], and may be harnessed by the brain. He argues that computers today are unable to have intelligence because they are algorithmically deterministic systems. He argues against the viewpoint that the rational processes of the mind are completely algorithmic and can thus be duplicated by a sufficiently complex computer.<ref name="Penrose-2016">{{Cite book|last=Penrose|first=Roger|url=https://books.google.com/books?id=X28sDwAAQBAJ&q=G%C3%B6del's+incompleteness+theorem|title=The Emperor's New Mind: Concerning Computers, Minds, and the Laws of Physics|date=2016|publisher=Oxford University Press|isbn=978-0-19-878492-0|language=en|access-date=7 December 2021|archive-date=19 November 2021|archive-url=https://web.archive.org/web/20211119091917/https://books.google.com/books?id=X28sDwAAQBAJ&q=G%C3%B6del%27s+incompleteness+theorem|url-status=live}}</ref> This contrasts with supporters of [[computational theory of mind|strong artificial intelligence]], who contend that thought can be simulated algorithmically. He bases this on claims that consciousness transcends [[formal logic]] because factors such as the insolubility of the [[halting problem]] and [[Gödel's incompleteness theorem]] prevent an algorithmically based system of logic from reproducing such traits of human intelligence as mathematical insight.<ref name="Penrose-2016" /> These claims were originally espoused by the philosopher [[John Lucas (philosopher)|John Lucas]] of [[Merton College, Oxford|Merton College]], [[University of Oxford|Oxford]].<ref>{{Cite web|title=In Memoriam: John Lucas|url=https://www.philosophy.ox.ac.uk/article/in-memoriam-john-lucas|access-date=7 October 2020|website=www.philosophy.ox.ac.uk|language=en|archive-date=9 October 2020|archive-url=https://web.archive.org/web/20201009111739/https://www.philosophy.ox.ac.uk/article/in-memoriam-john-lucas|url-status=live}}</ref>

The [[Penrose–Lucas argument]] about the implications of Gödel's incompleteness theorem for computational theories of human intelligence has been criticised by mathematicians, computer scientists and philosophers. Many experts in these fields assert that Penrose's argument fails, though different authors may choose different aspects of the argument to attack.<ref>Criticism of the Lucas/Penrose argument that intelligence can not be entirely algorithmic:

* [http://consc.net/mindpapers/6.1b MindPapers: 6.1b. Godelian arguments]. {{Webarchive|url=https://web.archive.org/web/20110611213335/http://consc.net/mindpapers/6.1b|date=11 June 2011}}.
* [http://users.ox.ac.uk/~jrlucas/Godel/referenc.html References for Criticisms of the Gödelian Argument]. {{Webarchive|url=https://web.archive.org/web/20200703180031/http://users.ox.ac.uk/~jrlucas/Godel/referenc.html|date=3 July 2020}}.
* [[George Boolos|Boolos, George]], et al. 1990. ''An Open Peer Commentary on The Emperor's New Mind.'' Behavioral and Brain Sciences 13 (4), p. 655.
* [[Martin Davis (mathematician)|Davis, Martin]] 1993. ''How subtle is Gödel's theorem? More on Roger Penrose.'' Behavioral and Brain Sciences, 16, pp. 611–612. Online version at Davis' faculty page at http://cs.nyu.edu/cs/faculty/davism/. {{Webarchive|url=https://web.archive.org/web/19981203160909/http://www.cs.nyu.edu/cs/faculty/davism/|date=3 December 1998}}.
* {{cite journal |last=Feferman |first=Solomon |author-link=Solomon Feferman |date=1996 |title=Penrose's Gödelian argument |journal=[[Psyche (consciousness journal)|Psyche]] |volume=2 |pages=21–32 |citeseerx=10.1.1.130.7027}}
* Krajewski, Stanislaw 2007. ''On Gödel's Theorem and Mechanism: Inconsistency or Unsoundness is Unavoidable in any Attempt to 'Out-Gödel' the Mechanist.'' Fundamenta Informaticae 81, pp. 173–181. Reprinted in [https://books.google.com/books?id=0jSS-3Bl06cC&pg=PA173 Topics in Logic, Philosophy and Foundations of Mathematics and Computer Science:In Recognition of Professor Andrzej Grzegorczyk (2008), p. 173]. {{Webarchive|url=https://web.archive.org/web/20161226205008/https://books.google.com/books?id=0jSS-3Bl06cC&lpg=PP1&pg=PA173|date=26 December 2016}}.
* {{cite journal |last1=LaForte |first1=Geoffrey |last2=Hayes |first2=Patrick J. |last3=Ford |first3=Kenneth M. |year=1998 |title=Why Gödel's Theorem Cannot Refute Computationalism |journal=Artificial Intelligence |volume=104 |issue=1–2 |pages=265–286 |doi=10.1016/s0004-3702(98)00052-6 |doi-access=free}}
* [[David Kellogg Lewis|Lewis, David K.]] 1969. ''[http://www2.units.it/etica/2003_1/7_monographica.doc Lucas against mechanism]. {{Webarchive|url=https://web.archive.org/web/20210225215326/http://www2.units.it/etica/2003_1/7_monographica.doc|date=25 February 2021}}''. Philosophy 44, pp. 231–233.
* [[Hilary Putnam|Putnam, Hilary]] 1995. ''Review of Shadows of the Mind.'' In Bulletin of the American Mathematical Society 32, pp. 370–373 (also see Putnam's less technical criticisms in his [https://www.nytimes.com/books/97/04/27/nnp/17540.html ''The New York Times'' review]. {{Webarchive|url=https://web.archive.org/web/20210309045619/https://archive.nytimes.com/www.nytimes.com/books/97/04/27/nnp/17540.html|date=9 March 2021}}).
Sources that indicate Penrose's argument is generally rejected:

* Bringsford, S. and Xiao, H. 2000. ''[http://kryten.mm.rpi.edu/refute.penrose.pdf A Refutation of Penrose's Gödelian Case Against Artificial Intelligence]. {{Webarchive|url=https://web.archive.org/web/20210224130103/http://kryten.mm.rpi.edu/refute.penrose.pdf|date=24 February 2021}}.'' [[Journal of Experimental and Theoretical Artificial Intelligence]] 12: 307–329. The authors write that it is "generally agreed" that Penrose "failed to destroy the computational conception of mind."
* In an article at {{cite web |title=King's College London – Department of Mathematics |url=http://www.mth.kcl.ac.uk/~llandau/Homepage/Math/penrose.html |url-status=dead |archive-url=https://web.archive.org/web/20010125011300/http://www.mth.kcl.ac.uk/~llandau/Homepage/Math/penrose.html |archive-date=25 January 2001 |access-date=22 October 2010}} L. J. Landau at the Mathematics Department of King's College London writes that "Penrose's argument, its basis and implications, is rejected by experts in the fields which it touches."
Sources that also note that different sources attack different points of the argument:

* Princeton Philosophy professor John Burgess writes in ''[http://www.princeton.edu/~jburgess/Montreal.doc On the Outside Looking In: A Caution about Conservativeness]. {{Webarchive|url=https://web.archive.org/web/20121019093317/http://www.princeton.edu/~jburgess/Montreal.doc|date=19 October 2012}}'', (published in Kurt Gödel: Essays for his Centennial, with the following comments found on [https://books.google.com/books?id=83Attf6BsJ4C&pg=PA131 pp. 131–132]. {{Webarchive|url=https://web.archive.org/web/20161227005431/https://books.google.com/books?id=83Attf6BsJ4C&lpg=PP1&pg=PA131|date=27 December 2016}}) that "the consensus view of logicians today seems to be that the Lucas–Penrose argument is fallacious, though as I have said elsewhere, there is at least this much to be said for Lucas and Penrose, that logicians are not unanimously agreed as to where precisely the fallacy in their argument lies. There are at least three points at which the argument may be attacked."
* [[Nachum Dershowitz]] 2005. ''[http://www.cs.tau.ac.il/~nachumd/papers/FourSonsOfPenrose.pdf The Four Sons of Penrose]. {{Webarchive|url=https://web.archive.org/web/20170809142617/http://www.cs.tau.ac.il/%7Enachumd/papers/FourSonsOfPenrose.pdf|date=9 August 2017}}'', in ''Proceedings of the Eleventh Conference on [[Logic for Programming, Artificial Intelligence and Reasoning]] (LPAR; Jamaica)'', G. Sutcliffe and [[Andrei Voronkov]], eds., Lecture Notes in Computer Science, vol. 3835, Springer-Verlag, Berlin, Germany, pp. 125–138.</ref> [[Marvin Minsky]], a leading proponent of artificial intelligence, was particularly critical, stating that Penrose "tries to show, in chapter after chapter, that human thought cannot be based on any known scientific principle." Minsky's position is exactly the opposite – he believed that humans are, in fact, machines, whose functioning, although complex, is fully explainable by current physics. Minsky maintained that "one can carry that quest [for scientific explanation] too far by only seeking new basic principles instead of attacking the real detail. This is what I see in Penrose's quest for a new basic principle of physics that will account for consciousness."<ref>Marvin Minsky. "Conscious Machines." Machinery of Consciousness, Proceedings, [[National Research Council of Canada]], 75th Anniversary Symposium on Science in Society, June 1991.</ref>

Penrose responded to criticism of ''The Emperor's New Mind'' with his follow-up 1994 book ''[[Shadows of the Mind]]'', and in 1997 with ''[[The Large, the Small and the Human Mind]]''. In those works, he also combined his observations with those of anesthesiologist [[Stuart Hameroff]].<ref>{{Cite web|title=Can Quantum Physics Explain Consciousness? One Scientist Thinks It Might|url=https://www.discovermagazine.com/the-sciences/can-quantum-physics-explain-consciousness-one-scientist-thinks-it-might|access-date=7 October 2020|website=Discover Magazine|language=en|archive-date=3 October 2020|archive-url=https://web.archive.org/web/20201003024544/https://www.discovermagazine.com/the-sciences/can-quantum-physics-explain-consciousness-one-scientist-thinks-it-might|url-status=live}}</ref>

Penrose and Hameroff have argued that [[consciousness]] is the result of quantum gravity effects in [[microtubule]]s, which they dubbed [[Orch-OR]] (orchestrated objective reduction). [[Max Tegmark]], in a paper in ''Physical Review E'',<ref>{{cite journal | last1 = Tegmark | first1 = Max | date = 2000 | title = The importance of quantum decoherence in brain processes | journal = [[Physical Review E]] | volume = 61 | issue = 4| pages = 4194–4206 | doi=10.1103/physreve.61.4194| pmid = 11088215 |arxiv = quant-ph/9907009 |bibcode = 2000PhRvE..61.4194T | s2cid = 17140058 }}</ref> calculated that the time scale of neuron firing and excitations in microtubules is slower than the [[quantum decoherence|decoherence]] time by a factor of at least 10,000,000,000. The reception of the paper is summed up by this statement in Tegmark's support: "Physicists outside the fray, such as IBM's [[John A. Smolin]], say the calculations confirm what they had suspected all along. 'We're not working with a brain that's near absolute zero. It's reasonably unlikely that the brain evolved quantum behavior'".<ref name="Tetlow 2007 166">
{{cite book
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|last=Tetlow
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|archive-url=https://web.archive.org/web/20211207185552/https://books.google.com/books?id=3mPI9rUuhJ8C&q=penrose+
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}}</ref> Tegmark's paper has been widely cited by critics of the Penrose–Hameroff position.

Phillip Tetlow, although himself supportive of Penrose's views, acknowledges that Penrose's ideas about the human thought process are at present a minority view in scientific circles, citing Minsky's criticisms and quoting science journalist [[Charles Seife]]'s description of Penrose as "one of a handful of scientists" who believe that the nature of consciousness suggests a quantum process.<ref name="Tetlow 2007 166"/>

In January 2014, Hameroff and Penrose ventured that a discovery of quantum vibrations in microtubules by Anirban Bandyopadhyay of the National Institute for Materials Science in Japan<ref>{{cite web |url=https://www.researchgate.net/profile/Anirban_Bandyopadhyay |title=Anirban Bandyopadhyay |access-date=22 February 2014 |archive-date=10 March 2014 |archive-url=https://web.archive.org/web/20140310053951/http://www.researchgate.net/profile/Anirban_Bandyopadhyay/ |url-status=live }}</ref> supports the hypothesis of [[Orchestrated objective reduction|Orch-OR theory]]. A reviewed and updated version of the theory was published along with critical commentary and debate in the March 2014 issue of ''[[Physics of Life Reviews]]''.<ref name="Hameroff2014">{{cite journal |author1=Hameroff |first=S. |author2=Penrose |first2=R. |date=2014 |title=Consciousness in the universe: A review of the 'Orch OR' theory |journal=Physics of Life Reviews |volume=11 |issue=1 |pages=39–78 |bibcode=2014PhLRv..11...39H |doi=10.1016/j.plrev.2013.08.002 |pmid=24070914 |doi-access=free}}</ref>