Lee Smolin: Wikis


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Lee Smolin

Lee Smolin at Harvard
Born 1955
New York City
Nationality American
Ethnicity Jewish
Fields Physicist
Institutions Perimeter Institute, University of Waterloo
Alma mater Hampshire College, Harvard University
Doctoral advisor Sidney Coleman, Stanley Deser
Other academic advisors Herbert Bernstein
His brother is David M. Smolin.

Lee Smolin (born 1955) is an American theoretical physicist, a researcher at the Perimeter Institute for Theoretical Physics, and an adjunct professor of physics at the University of Waterloo.

Smolin is best known for devising several different approaches to quantum gravity, in particular loop quantum gravity. He advocates that the two primary approaches to quantum gravity, loop quantum gravity and string theory, can be reconciled as different aspects of the same underlying theory. His research interests also include cosmology, elementary particle theory, the foundations of quantum mechanics, and theoretical biology.[1]


Early life

Smolin was born in New York City to Michael Smolin, an engineer, and Pauline Smolin, a playwright. His brother, David M. Smolin, became a professor in the Cumberland School of Law in Birmingham, Alabama.[2] He was educated at Hampshire College, where he studied with noted physicist Herb Bernstein. He received his Ph.D in theoretical physics from Harvard University in 1979.[1]

Theories and work


Fecund universes

The fecund universes theory (also called cosmological natural selection theory) of cosmology advanced by Lee Smolin suggests that the rules of biology apply on the grandest scales, and is often referred to as "cosmological natural selection". Smolin summarized the idea in a book aimed at a lay audience called The Life of the Cosmos.

The theory surmises that a collapsing black hole causes the emergence of a new universe on the "other side", whose fundamental constant parameters (speed of light, Planck length and so forth) may differ slightly from those of the universe where the black hole collapsed. Each universe therefore gives rise to as many new universes as it has black holes. Thus the theory contains the evolutionary ideas of "reproduction" and "mutation" of universes, but has no direct analogue of natural selection. However, given any universe that can produce black holes that successfully spawn new universes, it is possible that some number of those universes will reach heat death with unsuccessful parameters. So, in a sense, fecundity cosmological natural selection is one where universes could die off before successfully reproducing, just as any biological being can die without having children.[3]

Leonard Susskind who now promotes a similar string theory landscape, stated:

"I'm not sure why Smolin's idea didn't attract much attention. I actually think it deserved far more than it got."[4]

He writes many articles for the popular media, often promoting loop quantum gravity and criticizing the strength of support for string theory in the physics community.

Smolin also points out that the string theory landscape is not Popper falsifiable if other worlds are not observable. This is the subject of the Smolin-Susskind debate. There are then only two ways out: traversable wormholes connecting the different parallel worlds and "signal nonlocality", as described by Antony Valentini, a scientist at the Perimeter Institute.

In a critical review of The Life of the Cosmos, the astrophysicist Joe Silk suggested that our universe falls short by about four orders of magnitude of being maximal for the production of black holes.[5] In his book Questions of Truth, the particle physicist John Polkinghorne has another difficulty with Smolin's thesis, in that one cannot impose the consistent multiversal time which would be required to make the evolutionary dynamics work, since otherwise short-lived universes with few descendants would dominate long-lived universes with many[6]


The 2006 publication of The Trouble with Physics generated much controversy and debate about the merits of string theory. The book was criticised by some physicists, such as Joseph Polchinski[7] and Luboš Motl.[8] In his earlier book Three Roads to Quantum Gravity (2002), Smolin had stated that loop quantum gravity and string theory were essentially the same concept seen from different perspectives. In that book, he also favored the holographic principle. The Trouble with Physics, on the other hand, was strongly critical of string theory and of its prominence in contemporary theoretical physics. Smolin suggests that string theory suffers from serious deficiencies, and has an unhealthy near-monopoly in the particle theory community. He called for a diversity of approaches to quantum gravity, and argued that more attention should be paid to loop quantum gravity, an approach Smolin has devised. Finally, The Trouble with Physics is also broadly concerned with the role of controversy and the value of diverse approaches, in the ethics and process of science.

Smolin's thesis found support in one corner. In the same year as that in which The Trouble with Physics was published, Peter Woit also published a book for nonspecialists, whose conclusion was similar to Smolin's, namely that string theory was a fundamentally flawed research program.

  • Woit, Peter, 2006. Not Even Wrong: The Failure of String Theory & the Continuing Challenge to Unify the Laws of Physics. ISBN 0-224-07605-1 (Jonathan Cape), ISBN 0-465-09275-6 (Basic Books)

Smolin was recently named as #21 on Foreign Policy Magazine's list of Top 100 Public Intellectuals.[9] Smolin is also one of many physicists dubbed the "New Einstein" by the media[10].

Smolin-Susskind Debate

The Smolin-Susskind debate refers to the series of intense postings in 2004 by Lee Smolin and Leonard Susskind, concerning Smolin’s argument that the "Anthropic Principle cannot yield any falsifiable predictions, and therefore cannot be a part of science". [11].


Smolin does not believe that quantum mechanics is a "final theory":

"I am convinced that quantum mechanics is not a final theory. I believe this because I have never encountered an interpretation of the present formulation of quantum mechanics that makes sense to me. I have studied most of them in depth and thought hard about them, and in the end I still can't make real sense of quantum theory as it stands."[12]

In a 2009 article, Smolin has articulated the following philosophical views (the sentences in italics are quotations):

  1. There is only one universe. There are no others, nor is there anything isomorphic to it. Smolin denies the existence of a multiverse. Neither other universes nor copies of our universe -- within or outside -- exist. No copies can exist within the universe, because no subsystem can model precisely the larger system it is a part of. No copies can exist outside the universe, because the universe is by definition all there is. This principle also rules out the notion of a mathematical object isomorphic in every respect to the history of the entire universe, a notion more metaphysical than scientific.
  2. All that is real is real in a moment, which is a succession of moments. Anything that is true is true of the present moment. Not only is time real, but everything that is real is situated in time. Nothing exists timelessly.
  3. Everything that is real in a moment is a process of change leading to the next or future moments. Anything that is true is then a feature of a process in this process causing or implying future moments. This principle incorporates the notion that time is an aspect of causal relations. A reason for asserting it is that anything that existed for just one moment, without causing or implying some aspect of the world at a future moment, would be gone in the next moment. Things that persist must be thought of as processes leading to newly changed processes. An atom at one moment is a process leading to a different or a changed atom at the next moment.
  4. Mathematics is derived from experience as a generalization of observed regularities, when time and particularity are removed. Under this heading, Smolin distances himself from mathematical platonism, and gives his reaction to Eugene Wigner's " The Unreasonable Effectiveness of Mathematics in the Natural Sciences".

Personal life

He is married to Dina Graser, a communications lawyer in Toronto.


The following books are relatively non-technical, and can be appreciated by those who are not physicists.


  1. ^ a b Smolin's faculty page, Perimeter Institute.
  2. ^ David Smolin's Cumberland School of Law Faculty Page
  3. ^ Lee Smolin (2001). Tyson, Neil deGrasse and Soter, Steve. ed. Cosmic Horizons: Astronomy at the Cutting Edge. The New Press. pp. 148-152. ISBN 978-1565846029.  
  4. ^ Smolin vs. Susskind: the Anthropic Principle, between Smolin and Leonard Susskind, from the Edge Foundation website
  5. ^ Joe Silk (1997) "Holistic Cosmology," Science 277: 644.
  6. ^ John Polkinghorne and Nicholas Beale (2009) Questions of Truth. Westminster John Knox: 106-111.
  7. ^ Joseph Polchinski (2007) "All Strung Out?" a review of The Trouble with Physics and Not Even Wrong, American Scientist 95(1):1.
  8. ^ Luboš Motl (2004) The Reference Frame: a review of Lee Smolin's The Trouble with Physics
  9. ^ [1]
  10. ^ http://www.edge.org/3rd_culture/smolin/smolin_p1.html
  11. ^ [2]
  12. ^ Edge Foundation website: Smolin's response to the question "What do you believe is true even though you cannot prove it?"

External links


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