Sir Roger Penrose (born 8 August 1931) is
an English mathematical physicist, mathematician
and philosopher of science. He is Emeritus
Rouse Ball Professor of Mathematics in the
University of Oxford and Emeritus Fellow of
Wadham College, Oxford.
Penrose is known for his work in mathematical
physics, in particular for his contributions
to general relativity and cosmology. He has
received several prizes and awards, including
the 1988 Wolf Prize for physics, which he
shared with Stephen Hawking for the Penrose–Hawking
singularity theorems.
== Early life and academia ==
Born in Colchester, Essex, Roger Penrose is
a son of psychiatrist and geneticist Lionel
Penrose and Margaret Leathes, and the grandson
of the physiologist John Beresford Leathes
and his Russian wife, Sonia Marie Natanson.
Penrose told a Russian audience that his grandmother
had left St. Petersburg in the late 1880s.
His uncle was artist Roland Penrose, whose
son with photographer Lee Miller is Antony
Penrose. Penrose is the brother of physicist
Oliver Penrose and of chess Grandmaster Jonathan
Penrose. Penrose attended University College
School and University College, London, where
he graduated with a first class degree in
mathematics. In 1955, while still a student,
Penrose reintroduced the E. H. Moore generalised
matrix inverse, also known as the Moore–Penrose
inverse, after it had been reinvented by Arne
Bjerhammar in 1951. Having started research
under the professor of geometry and astronomy,
Sir W. V. D. Hodge, Penrose finished his PhD
at Cambridge in 1958, with a thesis on "tensor
methods in algebraic geometry" under algebraist
and geometer John A. Todd. He devised and
popularised the Penrose triangle in the 1950s,
describing it as "impossibility in its purest
form", and exchanged material with the artist
M. C. Escher, whose earlier depictions of
impossible objects partly inspired it. Escher's
Waterfall, and Ascending and Descending were
in turn inspired by Penrose.
As reviewer Manjit Kumar puts it:
As a student in 1954, Penrose was attending
a conference in Amsterdam when by chance he
came across an exhibition of Escher's work.
Soon he was trying to conjure up impossible
figures of his own and discovered the tribar
[see tri-bar for an image] – a triangle
that looks like a real, solid three-dimensional
object, but isn't. Together with his father,
a physicist and mathematician, Penrose went
on to design a staircase that simultaneously
loops up and down. An article followed and
a copy was sent to Escher. Completing a cyclical
flow of creativity, the Dutch master of geometrical
illusions was inspired to produce his two
masterpieces.
Having become a reader at Birkbeck College,
London (and having had his attention drawn
from pure mathematics to astrophysics by the
cosmologist Dennis Sciama, then at Cambridge)
it was in 1964 that, in the words of Kip Thorne
of Caltech, "Roger Penrose revolutionised
the mathematical tools that we use to analyse
the properties of spacetime". Until then work
on the curved geometry of general relativity
had been confined to configurations with sufficiently
high symmetry for Einstein's equations to
be soluble explicitly, and there was doubt
about whether such cases were typical. One
approach to this issue was by the use of perturbation
theory, as developed under the leadership
of John Archibald Wheeler at Princeton. The
other, more radically innovative, approach
initiated by Penrose was to overlook the detailed
geometrical structure of spacetime and instead
concentrate attention just on the topology
of the space, or at most its conformal structure,
since it is the latter — as determined by
the lay of the lightcones — that determines
the trajectories of lightlike geodesics, and
hence their causal relationships. The importance
of Penrose's epoch-making paper "Gravitational
collapse and space-time singularities" was
not only its result (roughly that if an object
such as a dying star implodes beyond a certain
point, then nothing can prevent the gravitational
field getting so strong as to form some kind
of singularity). It also showed a way to obtain
similarly general conclusions in other contexts,
notably that of the cosmological Big Bang,
which he dealt with in collaboration with
Dennis Sciama's most famous student, Stephen
Hawking.
It was in the local context of gravitational
collapse that the contribution of Penrose
was most decisive, starting with his 1969
cosmic censorship conjecture, to the effect
that any ensuing singularities would be confined
within a well-behaved event horizon surrounding
a hidden space-time region for which Wheeler
coined the term black hole, leaving a visible
exterior region with strong but finite curvature,
from which some of the gravitational energy
may be extractable by what is known as the
Penrose process, while accretion of surrounding
matter may release further energy that can
account for astrophysical phenomena such as
quasars.
Following up his "weak cosmic censorship hypothesis",
Penrose went on, in 1979, to formulate a stronger
version called the "strong censorship hypothesis".
Together with the BKL conjecture and issues
of nonlinear stability, settling the censorship
conjectures is one of the most important outstanding
problems in general relativity. Also from
1979 dates Penrose's influential Weyl curvature
hypothesis on the initial conditions of the
observable part of the universe and the origin
of the second law of thermodynamics. Penrose
and James Terrell independently realised that
objects travelling near the speed of light
will appear to undergo a peculiar skewing
or rotation. This effect has come to be called
the Terrell rotation or Penrose–Terrell
rotation.
In 1967, Penrose invented the twistor theory
which maps geometric objects in Minkowski
space into the 4-dimensional complex space
with the metric signature (2,2).
Penrose is well known for his 1974 discovery
of Penrose tilings, which are formed from
two tiles that can only tile the plane nonperiodically,
and are the first tilings to exhibit fivefold
rotational symmetry. Penrose developed these
ideas based on the article Deux types fondamentaux
de distribution statistique (1938; an English
translation Two Basic Types of Statistical
Distribution) by Czech geographer, demographer
and statistician Jaromír Korčák. In 1984,
such patterns were observed in the arrangement
of atoms in quasicrystals. Another noteworthy
contribution is his 1971 invention of spin
networks, which later came to form the geometry
of spacetime in loop quantum gravity. He was
influential in popularising what are commonly
known as Penrose diagrams (causal diagrams).
In 1983, Penrose was invited to teach at Rice
University in Houston, by the then provost
Bill Gordon. He worked there from 1983 to
1987.
== Later activity ==
In 2004, Penrose released The Road to Reality:
A Complete Guide to the Laws of the Universe,
a 1,099-page comprehensive guide to the Laws
of Physics that includes an explanation of
his own theory. The Penrose Interpretation
predicts the relationship between quantum
mechanics and general relativity, and proposes
that a quantum state remains in superposition
until the difference of space-time curvature
attains a significant level.Penrose is the
Francis and Helen Pentz Distinguished Visiting
Professor of Physics and Mathematics at Pennsylvania
State University. He is also a member of the
Editorial Board of The Astronomical Review
and of the Advisory Board of Universe.
== An earlier universe ==
In 2010, Penrose reported possible evidence,
based on concentric circles found in WMAP
data of the CMB sky, of an earlier universe
existing before the Big Bang of our own present
universe. He mentions this evidence in the
epilogue of his 2010 book Cycles of Time,
a book in which he presents his reasons, to
do with Einstein's field equations, the Weyl
curvature C, and the Weyl curvature hypothesis
(WCH), that the transition at the Big Bang
could have been smooth enough for a previous
universe to survive it. He made several conjectures
about C and the WCH, some of which were subsequently
proved by others, and where he also popularized
his conformal cyclic cosmology (CCC) theory.
In simple terms, he believes that the singularity
in Einstein's field equation at the Big Bang
is only an apparent singularity, similar to
the well-known apparent singularity at the
event horizon of a black hole. The latter
singularity can be removed by a change of
coordinate system, and Penrose proposes a
different change of coordinate system that
will remove the singularity at the big bang.
One implication of this is that the major
events at the Big Bang can be understood without
unifying general relativity and quantum mechanics,
and therefore we are not necessarily constrained
by the Wheeler–DeWitt equation, which disrupts
time. Alternatively, one can use the Einstein–Maxwell–Dirac
equations.
== Physics and consciousness ==
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. 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). Penrose uses a variant of
Turing's halting theorem to demonstrate that
a system can be deterministic without being
algorithmic. (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.)
Penrose believes that such deterministic yet
non-algorithmic processes may come into play
in the quantum mechanical wave function reduction,
and may be harnessed by the brain. He argues
that the present computer is unable to have
intelligence because it is an algorithmically
deterministic system. 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.
This contrasts with supporters of strong artificial
intelligence, who contend that thought can
be simulated algorithmically. He bases this
on claims that consciousness transcends formal
logic because things 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. These
claims were originally espoused by the philosopher
John Lucas of Merton College, Oxford.
The Penrose–Lucas argument about the implications
of Gödel's incompleteness theorem for computational
theories of human intelligence has been widely
criticised by mathematicians, computer scientists
and philosophers, and the consensus among
experts in these fields seems to be that the
argument fails, though different authors may
choose different aspects of the argument to
attack. 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."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 that
of anesthesiologist Stuart Hameroff.
Penrose and Hameroff have argued that consciousness
is the result of quantum gravity effects in
microtubules, which they dubbed Orch-OR (orchestrated
objective reduction). Max Tegmark, in a paper
in Physical Review E, calculated that the
time scale of neuron firing and excitations
in microtubules is slower than the 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'".
Tegmark's paper has been widely cited by critics
of the Penrose–Hameroff position.
In their reply to Tegmark's paper, also published
in Physical Review E, the physicists Scott
Hagan, Jack Tuszyński and Hameroff claimed
that Tegmark did not address the Orch-OR model,
but instead a model of his own construction.
This involved superpositions of quanta separated
by 24 nm rather than the much smaller separations
stipulated for Orch-OR. As a result, Hameroff's
group claimed a decoherence time seven orders
of magnitude greater than Tegmark's, but still
well short of the 25 ms required if the quantum
processing in the theory was to be linked
to the 40 Hz gamma synchrony, as Orch-OR suggested.
To bridge this gap, the group made a series
of proposals.
They supposed that the interiors of neurons
could alternate between liquid and gel states.
In the gel state, it was further hypothesized
that the water electrical dipoles are oriented
in the same direction, along the outer edge
of the microtubule tubulin subunits. Hameroff
et al. proposed that this ordered water could
screen any quantum coherence within the tubulin
of the microtubules from the environment of
the rest of the brain. Each tubulin also has
a tail extending out from the microtubules,
which is negatively charged, and therefore
attracts positively charged ions. It is suggested
that this could provide further screening.
Further to this, there was a suggestion that
the microtubules could be pumped into a coherent
state by biochemical energy. Finally, he suggested
that the configuration of the microtubule
lattice might be suitable for quantum error
correction, a means of holding together quantum
coherence in the face of environmental interaction.
Hameroff, in a lecture in part of a Google
Tech talks series exploring quantum biology,
gave an overview of current research in the
area, and responded to subsequent criticisms
of the Orch-OR model. In addition to this,
a 2011 paper by Roger Penrose and Stuart Hameroff
published in the fringe Journal of Cosmology
gives an updated model of their Orch-OR theory,
in light of criticisms, and discusses the
place of consciousness within the universe.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.In January 2014 Hameroff
and Penrose claimed that a discovery of quantum
vibrations in microtubules by Anirban Bandyopadhyay
of the National Institute for Materials Science
in Japan confirms the hypothesis of 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.
== Personal life ==
=== Family life ===
Penrose is married to Vanessa Thomas, director
of Academic Development at Cokethorpe School
and former head of mathematics at Abingdon
School, with whom he has one son. He has three
sons from a previous marriage to American
Joan Isabel Wedge, whom he married in 1959.
=== Religious views ===
During an interview with BBC Radio 4 on September
25, 2010, Penrose states, "I'm not a believer
myself. I don't believe in established religions
of any kind. I would say I'm an atheist",
during a discussion on the Big Bang Theory.
In the film A Brief History of Time, he said,
"I think I would say that the universe has
a purpose, it's not somehow just there by
chance ... some people, I think, take the
view that the universe is just there and it
runs along – it's a bit like it just sort
of computes, and we happen somehow by accident
to find ourselves in this thing. But I don't
think that's a very fruitful or helpful way
of looking at the universe, I think that there
is something much deeper about it." Penrose
is a Distinguished Supporter of Humanists
UK.
== Awards and honours ==
Penrose has been awarded many prizes for his
contributions to science. He was elected a
Fellow of the Royal Society (FRS) in 1972.
In 1975, Stephen Hawking and Penrose were
jointly awarded the Eddington Medal of the
Royal Astronomical Society. In 1985, he was
awarded the Royal Society Royal Medal. Along
with Stephen Hawking, he was awarded the prestigious
Wolf Foundation Prize for Physics in 1988.
In 1989 he was awarded the Dirac Medal and
Prize of the British Institute of Physics.
In 1990 Penrose was awarded the Albert Einstein
Medal for outstanding work related to the
work of Albert Einstein by the Albert Einstein
Society. In 1991, he was awarded the Naylor
Prize of the London Mathematical Society.
From 1992 to 1995 he served as President of
the International Society on General Relativity
and Gravitation.
In 1994, Penrose was knighted for services
to science. In the same year he was also awarded
an Honorary Degree (Doctor of Science) by
the University of Bath. In 1998, he was elected
Foreign Associate of the United States National
Academy of Sciences. In 2000 he was appointed
to the Order of Merit. In 2004 he was awarded
the De Morgan Medal for his wide and original
contributions to mathematical physics. To
quote the citation from the London Mathematical
Society:
His deep work on General Relativity has been
a major factor in our understanding of black
holes. His development of Twistor Theory has
produced a beautiful and productive approach
to the classical equations of mathematical
physics. His tilings of the plane underlie
the newly discovered quasi-crystals.
In 2005 Penrose was awarded an honorary doctorate
by Warsaw University and Katholieke Universiteit
Leuven (Belgium), and in 2006 by the University
of York. In 2008 Penrose was awarded the Copley
Medal. He is also a Distinguished Supporter
of Humanists UK and one of the patrons of
the Oxford University Scientific Society.
In 2011, Penrose was awarded the Fonseca Prize
by the University of Santiago de Compostela.
In 2012, Penrose was awarded the Richard R.
Ernst Medal by ETH Zürich for his contributions
to science and strengthening the connection
between science and society. In 2015 Penrose
was awarded an honorary doctorate by CINVESTAV-IPN
(Mexico).
== Depictions in popular culture ==
In the 2004 BBC TV movie Hawking, Penrose
is played by Tom Ward
In the 2014 movie The Theory of Everything,
Penrose is played by Christian McKay
== Works ==
=== Popular publications ===
The Emperor's New Mind: Concerning Computers,
Minds, and The Laws of Physics (1989)
Shadows of the Mind: A Search for the Missing
Science of Consciousness (1994)
The Road to Reality: A Complete Guide to the
Laws of the Universe (2004)(New Edition from
Vintage Digital; 31 Mar. 2016)
Cycles of Time: An Extraordinary New View
of the Universe (2010)
Fashion, Faith, and Fantasy in the New Physics
of the Universe (2016)
==== Co-authored ====
The Nature of Space and Time (with Stephen
Hawking) (1996)
The Large, the Small and the Human Mind (with
Abner Shimony, Nancy Cartwright, and Stephen
Hawking) (1997)
White Mars - The Mind Set Free (with Brian
Aldiss) (1999)
=== Academic books ===
Techniques of Differential Topology in Relativity
(1972, ISBN 0-89871-005-7)
Spinors and Space-Time: Volume 1, Two-Spinor
Calculus and Relativistic Fields (with Wolfgang
Rindler, 1987) ISBN 0-521-33707-0 (paperback)
Spinors and Space-Time: Volume 2, Spinor and
Twistor Methods in Space-Time Geometry (with
Wolfgang Rindler, 1988) (reprint), ISBN 0-521-34786-6
(paperback)
=== Foreword to other books ===
Foreword to Beating the Odds: The Life and
Times of E. A. Milne, written by Meg Weston
Smith. Published by World Scientific Publishing
Co in June 2013.
Foreword to Quantum Aspects of Life by Derek
Abbott, Paul C. W. Davies, and Arun K. Pati.
Published by Imperial College Press in 2008.
Foreword to Fearful Symmetry by Anthony Zee's.
Published by Princeton University Press in
2007.
Foreword to "A Computable Universe" by Hector
Zenil. Published by World Scientific Publishing
Co in December 2012.
Foreword to “The Map and the Territory:
Exploring the foundations of science, thought
and reality” by Shyam Wuppuluri and Francisco
Antonio Doria. Published by Springer in “The
frontiers collection”, 2018.
== See also ==
Conformal cyclic cosmology
Illumination problem
Orchestrated objective reduction
Penrose graphical notation
Quantum Aspects of Life
Quantum mind
== Notes ==
== References ==
== Further reading ==
Ferguson, Kitty (1991). Stephen Hawking: Quest
For A Theory of Everything. Franklin Watts.
ISBN 0-553-29895-X.
Misner, Charles; Thorne, Kip S. & Wheeler,
John Archibald (1973). Gravitation. San Francisco:
W. H. Freeman. ISBN 0-7167-0344-0. (See Box
34.2.)
== External links ==
Roger Penrose on IMDb
Awake in the Universe - Penrose debates how
creativity, the most elusive of faculties,
has helped us unlock the country of the mind
and the mysteries of the cosmos with Bonnie
Greer.
Dangerous Knowledge on YouTube – Penrose
was one of the principal interviewees in a
BBC documentary about the mathematics of infinity
directed by David Malone
Penrose's new theory "Aeons Before the Big
Bang?":
Original 2005 lecture: "Before the Big Bang?
A new perspective on the Weyl curvature hypothesis"
(Isaac Newton Institute for Mathematical Sciences,
Cambridge, 11 Nov 2005).
Original publication: "Before the Big Bang:
an outrageous new perspective and its implications
for particle physics". Proceedings of EPAC
2006. Edinburgh. 2759–2762 (cf. also Hill,
C.D. & Nurowski, P. (2007) "On Penrose's 'Before
the Big Bang' ideas". Ithaca)
Revised 2009 lecture: "Aeons Before the Big
Bang?" (Georgia Institute of Technology, Center
for Relativistic Astrophysics)
BBC interview on the new theory on YouTube
Roger Penrose on The Forum
Penrose on sidestepping reason on YouTube
O'Connor, John J.; Robertson, Edmund F., "Roger
Penrose", MacTutor History of Mathematics
archive, University of St Andrews.
Hilary Putnam's review of Penrose's 'Shadows
of the Mind' claiming that Penrose's use of
Godel's Incompleteness Theorem is fallacious
Beyond the Doubting of a Shadow: A Reply to
Commentaries on Shadows of the Mind at the
Wayback Machine (archived 18 June 2008)
Penrose Tiling found in Islamic Architecture
Two theories for the formation of quasicrystals
resembling Penrose tilings
Tegmark, Max (2000). "The importance of quantum
decoherence in brain processes". Physical
Review E. 61: 4194–4206. arXiv:quant-ph/9907009.
Bibcode:2000PhRvE..61.4194T. doi:10.1103/physreve.61.4194."Biological
feasibility of quantum states in the brain"
– (a disputation of Tegmark's result by
Hagan, Hameroff, and Tuszyński)
Tegmarks's rejoinder to Hagan et al.
"Toilet Paper Plagiarism" at the Wayback Machine
(archived 12 March 2005) – D. Trull about
Penrose's lawsuit concerning the use of his
Penrose tilings on toilet paper
Roger Penrose: A Knight on the tiles (Plus
Magazine)
Penrose's Gifford Lecture biography
Quantum-Mind
Audio: Roger Penrose in conversation on the
BBC World Service discussion show
Roger Penrose speaking about Hawking's new
book on Premier Christian Radio
"The Cyclic Universe – A conversation with
Roger Penrose", Ideas Roadshow, 2013
Forbidden crystal symmetry in mathematics
and architecture, filmed event at the Royal
Institution, October 2013
Oxford Mathematics Interviews: "Extra Time:
Professor Sir Roger Penrose in conversation
with Andrew Hodges." These two films explore
the development of Sir Roger Penrose’s thought
over more than 60 years, ending with his most
recent theories and predictions. 51 min and
42 min. (Mathematical Institute)
BBC Radio 4 - The Life Scientific - Roger
Penrose on Black Holes - 22 November 2016
Sir Roger Penrose talks to Jim Al-Khalili
about his trailblazing work on how black holes
form, the problems with quantum physics and
his portrayal in films about Stephen Hawking.
The Penrose Institute Website
