“Whereas originally the hopes for string theory, and its descendants, were that some kind of uniqueness would be arrived at, whereby the theory would supply mathematical explanations for the measured numbers of experimental physics, the string theorists were driven to find refugee in the strong anthropic argument in an attempt to narrow down an absolutely vast number of alternatives. In my own view, this a very sad and unhelpful place for a theory to find itself.”

—  Roger Penrose, book Fashion, Faith, and Fantasy in the New Physics of the Universe

Source: Fashion, Faith, and Fantasy in the New Physics of the Universe (2016), Ch. 3 Fantasy, p 322

Adopted from Wikiquote. Last update Feb. 23, 2026. History

Help us to complete the source, original and additional information

Do you have more details about the quote "Whereas originally the hopes for string theory, and its descendants, were that some kind of uniqueness would be arrived…" by Roger Penrose?
Roger Penrose photo
Roger Penrose15
English mathematical physicist, recreational mathematician … 1931

Related quotes

Lee Smolin photo

“Many of us believed in the possibility of a principled explanation for the laws of nature. We hoped to discover a short list of principles, which could be realized in a unique theory, which would retrodict the standard model and uniquely predict the physics to be discovered beyond it. The shocking implication of the results of Strominger reported in 1986 was that it was not to be, at least within the confines of string theory. …String theory offered more, however… It offered the promise of a setting in which the different perturbative string theories are realized as expansions around solutions of a still more fundamental theory. …That more fundamental theory would have to be background independent…”

Lee Smolin (1955) American cosmologist

"A perspective on the landscape problem" arXiv (Feb 15, 2012)

David Gross photo

“String theory was not invented to describe gravity; instead it originated in an attempt to describe the strong interactions, wherein mesons can be thought of as open strings with quarks at their ends. The fact that the theory automatically described closed strings as well, and that closed strings invariably produced gravitons and gravity, and that the resulting quantum theory of gravity was finite and consistent is one of the most appealing aspects of the theory.”

David Gross (1941) American particle physicist and string theorist

"Einstein and the Search for Unification", p. 10 https://books.google.com/books?id=rEaUIxukvy4C&pg=PA10, in The legacy of Albert Einstein: a collection of essays in celebration of the year of physics (2007)

Lee Smolin photo

“Since the 1960s, particle theory had been split into two groups: those following the atomism of the quark theory and those who had followed the anti-atomism of that had led from the bootstrap program to the string theory. What happened in 1984 was that it was realised that string theory could combine and satisfy the aspirations of both approaches to fundamental physics. Thus, the community of gauge theorists, driven by the failure of the proton decay experiments to search for new ideas that could unify physics, all of a sudden encountered their old friends, the string theorists, in the middle of what might be called a desert of disappointed expectations.”

Lee Smolin book The Life of the Cosmos

The Life of the Cosmos (1997)

John C. Baez photo

“The most popular approach to quantum gravity is string theory. Despite decades of hard work by many very smart people, it's far from clear that this theory is successful. It's made no predictions that have been confirmed by experiment. In fact, it's made few predictions that we have any hope of testing anytime soon! Finding certain sorts of particles at the big new particle accelerator near Geneva would count as partial confirmation, but string theory says very little about the details of what we should expect. In fact, thanks to the vast "landscape" of string theory models that researchers are uncovering, it keeps getting harder to squeeze specific predictions out of this theory.”

John C. Baez (1961) American mathematician and mathematical physicist

[2008, http://www.edge.org/q2008/q08_5.html#baez, Should I be thinking about quantum gravity? (essay at the World Question Center), edge.org]

David Gross photo

“Why is space-time doomed? There are many reasons, among which: In string theory we can change the dimension of space-time by changing the strength of the string force. Thus, the so-called II-A string theory, which semi-classically describes closed strings moving in ten-dimensional flat space for very weak coupling is dual for strong coupling to a theory, called M-theory, that at low energies is described by eleven-dimensional supergravity. By increasing the string coupling we can grow an extra dimension. How can the spatial continuum be fundamental if the number of spatial dimensions can be so changed?”

David Gross (1941) American particle physicist and string theorist

"Einstein and the Search for Unification", p. 11 https://books.google.com/books?id=rEaUIxukvy4C&pg=PA11, in The legacy of Albert Einstein: a collection of essays in celebration of the year of physics (2007)

Martinus J. G. Veltman photo

“The reader may ask why in this book string theory and supersymmetry have not been discussed. … The fact is that this book is about physics and this implies that the theoretical ideas discussed must be supported by experimental facts. Neither supersymmetry and string theory satisfy this criterion. They are figments of the theoretical mind.”

Martinus J. G. Veltman (1931) Dutch physicist

[Martinus Veltman, Facts and mysteries in elementary particle physics, World Scientific, 2003, 981238149X, 308, https://books.google.com/books?id=CNCHDIobj0IC&pg=PA308]

Edward Witten photo

“It is very possible that a proper understanding of string theory will make the space-time continuum melt away…. String theory is a miracle through and through.”

Edward Witten (1951) American theoretical physicist

as quoted by K.C. Cole, "A Theory of Everything" New York Times Magazine (1987) Oct.18

Roger Penrose photo

“The idea of having an ambient space-time of some specific dimension seems to play less of a role of string theory than in conventional physics, and certainly less than the kind of role that I would myself feel comfortable with. It is particularly difficult to assess the functional freedom that is involved in a physical theory unless one has a clear idea of its actual space-time dimensionality.”

Roger Penrose book Fashion, Faith, and Fantasy in the New Physics of the Universe

Ch. 1, Mathematical Elegance as a Driving Force, p. 62 https://books.google.com/books?id=T09kCwAAQBAJ&amp;pg=PA62. <br class="br">Fashion, Faith, and Fantasy in the New Physics of the Universe (2016)

Edward Witten photo

“Replacing particles by strings is a naive-sounding step, from which many other things follow. In fact, replacing Feynman graphs by Riemann surfaces has numerous consequences: 1. It eliminates the infinities from the theory. …2. It greatly reduces the number of possible theories. …3. It gives the first hint that string theory will change our notions of spacetime. Just as in QCD, so also in gravity, many of the interesting questions cannot be answered in perturbation theory. In string theory, to understand the nature of the Big Bang, or the quantum fate of a black hole, or the nature of the vacuum state that determines the properties of the elementary particles, requires information beyond perturbation theory… Perturbation theory is not everything. It is just the way the [string] theory was discovered.”

Edward Witten (1951) American theoretical physicist

"The Past and Future of String Theory" in The Future of Theoretical Physics and Cosmology: Celebrating Stephen Hawking's Contributions to Physics (2003) ed. G.W. Gibbons, E.P.S. Shellard & S.J. Rankin

“String theory has a close relationship to quantum field theory — indeed in some sense it encompasses all interesting quantum field theories.”

Michael Green (physicist) (1946) British physicist

Related topics