ADVERTISEMENT
  About the SA Blog Network













Cross-Check

Cross-Check


Critical views of science in the news
Cross-Check Home

Quantum Gravity Expert Says “Philosophical Superficiality” Has Harmed Physics

The views expressed are those of the author and are not necessarily those of Scientific American.


Email   PrintPrint



As readers of this blog know, late last spring I spoke at a cool conference in England called How the Light Gets In, where I hung out with all kinds of professional reality-ponderers. I’ve already posted Q&As with two fellow speakers I shared housing with: biologist Rupert Sheldrake, who urges scientists to take telepathy more seriously; and physicist George Ellis, who deplores the philosophical philistinism of some fellow physicists. Below is my Q&A with another housemate, physicist Carlo Rovelli of Aix-Marseille University and the Intitut Universitaire de France. I interviewed Rovelli by phone in the early 1990s when I was writing a story for Scientific American about loop quantum gravity, a quantum-mechanical version of gravity proposed by Rovelli, Lee Smolin and Abhay Ashtekar. (General relativity, Einstein’s theory of gravity, is notoriously difficult to reconcile with quantum mechanics.) I was thrilled to meet Rovelli face to face, especially since he turned out to be, like Sheldrake and Ellis, a good as well as smart guy. Rovelli is the author of a leading textbook on quantum gravity and a biography about the ancient Greek philosopher Anaximander (discussed below). For more on Rovelli’s views on physics and philosophy, see this 2012 conversation with him on Edge.org.

Carlo Rovelli: "Theoretical physics has not done great in the last decades. Why? Well, one of the reasons, I think, is that it got trapped in a wrong philosophy."

Horgan: Why did you become a physicist?

Rovelli: I was young in the sixties and seventies, and shared the dream of my generation: changing the world and make it more just and gentle.  We lost.  I did not know what to do next. I found physics, where, instead, revolutions succeed.  I got in love with it.  It has been a passion that hasn’t ended.

Horgan: Has physics lived up to your expectations?

Rovelli: It has been much better than I expected.  Infinite fun and enthusiasm.  Investigating the secrets of the world.  Thinking things that nobody else has thought before.  Great adventures in thinking.   Great companions of travel.  Fantastic.

Horgan: What is loop quantum gravity?

Rovelli: It is, in my humble opinion, the best tentative theory of quantum gravity we have at present.  We do not know if it is right.  But we know there is a problem, and this is the best possible solution found so far for this problem.

Horgan: Is it still a viable contender as a unified theory?

Rovelli: “Unified theory” generally means a theory that unifies all forces and all fields: a “theory of everything.”   Loop quantum gravity doesn’t have anything to do with this.  [Horgan note: LQG doesn't include electromagnetism or the nuclear forces.] I think that for the moment we know nothing about a “unified theory” and the attempts to write it are by far premature and ill conceived.  So, LQG is not a contender as a unified theory.  Much more humbly, it is just a tentative solution for a simpler problem: describing the quantum aspects of gravity. Which is to say the quantum aspects of spacetime.  This is hard enough. But it is a problem that we have chances to solve, because we have the ingredients.

Horgan: Do multiverse theories and quantum gravity theories deserve to be taken seriously if they cannot be falsified?

Rovelli: No.

Horgan: Do you ever think it’s time for physicists to abandon the quest for a unified theory?

Rovelli: The “quest for a unified theory” is a misconception.  Physicists never really searched for it.  They stumbled upon string theory, which to some appeared as a possible unification of everything, and, for lack of imagination, put too much energy into strings.  When the enthusiasm for strings begun to fade, many felt lost.  Now that supersymmetry is not showing up where string theorists expected it, it is a disarray.

Horgan: Can physics—or science in general—ever completely solve the mystery of the universe?

Rovelli: What is the “mystery of the universe”?  There isn’t a “mystery of the universe.”   There is an ocean of things we do not know.  Many of them we’ll figure out, if we continue to be somewhat rational and do not kill one another first (which is well possible.)  There will always be plenty of things that we will not understand, I think, but what do I know? In any case, we are very very very far from any complete comprehension of everything we would like to know.

Horgan: Can science attain absolute truth?

Rovelli: I have no idea what “absolute truth” means. I think that science is the attitude of those who find funny the people saying they know something is absolute truth.  Science is the awareness that our knowledge is constantly uncertain.  What I know is that there are plenty of things that science does not understand yet. And science is the best tool found so far for reaching reasonably reliable knowledge.

Horgan: What’s your opinion of the recent philosophy-bashing by Stephen Hawking, Lawrence Krauss and Neil deGrasse Tyson?

Rovelli: Seriously: I think they are stupid in this.   I have admiration for them in other things, but here they have gone really wrong.  Look: Einstein, Heisenberg, Newton, Bohr…. and many many others of the greatest scientists of all times, much greater than the names you mention, of course, read philosophy, learned from philosophy, and could have never done the great science they did without the input they got from philosophy, as they claimed repeatedly.  You see: the scientists that talk philosophy down are simply superficial: they have a philosophy (usually some ill-digested mixture of Popper and Kuhn) and think that this is the “true” philosophy, and do not realize that this has limitations.

Here is an example: theoretical physics has not done great in the last decades. Why? Well, one of the reasons, I think, is that it got trapped in a wrong philosophy: the idea that you can make progress by guessing new theory and disregarding the qualitative content of previous theories.  This is the physics of the “why not?”  Why not studying this theory, or the other? Why not another dimension, another field, another universe?    Science has never advanced in this manner in the past.  Science does not advance by guessing. It advances by new data or by a deep investigation of the content and the apparent contradictions of previous empirically successful theories.  Quite remarkably, the best piece of physics done by the three people you mention is Hawking’s black-hole radiation, which is exactly this.  But most of current theoretical physics is not of this sort.  Why?  Largely because of the philosophical superficiality of the current bunch of scientists.

Horgan: You have written about the Greek thinker Anaximander. Who was he, and why do you find him interesting?

Rovelli: He is the guy who understood that the Earth is a stone that floats in the middle of the Sky without falling down. He understood that the Sky is not just above out head: it is also under our feet. It surrounds us in every direction.   He is the only one in the history of our planet who understood this, and convinced everybody else that this is the case. In fact, he has done much more than this, but this is his greatest achievement.  I find him immensely interesting because he represents one of the main steps in the development of scientific thinking.  He is a giant.

Horgan: Do you agree with philosopher Thomas Nagel that science needs a new paradigm to account for the emergence of life and consciousness in the cosmos?

Rovelli: No.  When we do not understand something, people are tempted to think that “some new paradigm” is needed, or a “great mystery” is there.   Then we understand it, and all fog dissolves.

Horgan: Do you believe in God?

Rovelli: No.  But perhaps I should qualify the answer, because like this it is bit too rude and simplistic. I do not understand what “to believe in God” means. The people that “believe in God” seem like Martians to me.  I do not understand them.  I suppose this means that I “do not believe in God”. If the question is whether I think that there is a person who has created Heavens and Earth, and responds to our prayers, then definitely my answer is no, with much certainty.

If the question is whether I believe that “God” is a powerful something in the people, which causes a lot of disasters but also a lot of good, then of course I believe it.   In fact, I am extremely curious about religion. I think that we should study what is religion much more than what is done. There is a sort of taboo in this, a sort of respect towards people who “believe in God”, which makes it difficult to understand better.

I think that viewing the “belief in God” just as a bunch of silly superstitions is wrong. The “belief in God” is one form of human religious attitude, and human religious attitude is something very general and universal about our functioning. Something which is important for man, and we have not yet understood.

Horgan: Are science and religion compatible?

Rovelli: Of course yes: you can be great in solving Maxwell’s equations and pray to God in the evening.  But there is an unavoidable clash between science and certain religions, especially some forms of Christianity and Islam, those that pretend to be repositories of “absolute Truths.”  The problem is not that scientists think they know everything. It is the opposite: scientists know that there are things we simply do not know, and naturally question those who pretend to know.   Many religious people are disturbed by this, and have difficulty in coping with it.  The religious person says, “I know that God has created light saying, ‘Fiat Lux.’”  The scientist does not believe the story. The religious people feel threatened.  And here the clash develops.  But not all religions are like that. Many forms of Buddhism, for instance, have no difficulty with the continual critical attitude of science. Monotheistic religions, and in particular Islam and Christianity, are sometimes less intelligent.

I have an idea about the source of the conflict: there is beautiful research by anthropologists in Australia which shows that religious beliefs are often considered a-temporal but in reality change continuously and adapt to new conditions, new knowledge and so on.  This was discovered by comparing religious beliefs held by native Australians studied by anthropologists in the thirties and, much later, in the seventies.  So, in a natural situation, religious beliefs adapt to the change in man’s culture and knowledge.  The problem with Islam and Christianity is that many centuries ago somebody had the idea of writing down beliefs. So now some religious people are stuck with the culture and knowledge of centuries ago. They are fish trapped in a pond of old water.

Horgan: Have you ever accepted money from a military organization?

Rovelli: No. In my country military service was compulsory when I was a young man.  I refused to join the army and was briefly detained for this.

Horgan: Do you think physicists—and scientists in general–have a moral responsibility to oppose militarism?

Rovelli: I think that we have a moral responsibility to oppose war as human beings, not as physicists or scientists.  I think that the problem is that everybody “opposes the war” in words, but then many people are ready to make exceptions to serve their interests, defend their power and economical superiority. And these people hide this behind “feel good” words like “help people” or “fight terrorism”.  I found this morally disgusting.  I wish people were less religious and more moral .

HorganIn 2002 I bet physicist Michio Kaku $1,000 that by 2020 “no one will have won a Nobel Prize for work on superstring theory, membrane theory, or some other unified theory describing all the forces of nature.” Who do you think is going to win? [Horgan note: Lee Smolin was originally going to bet against me but backed out at the last minute, the big chicken.]

Rovelli: You.  No doubt.

Postscript from Horgan: In the comments section, you can see that Carlo Rovelli posts responses to some early comments on his remarks. I’m copying his responses here for easier access.

A few answers from carlo rovelli:

- to “lakefield”: I actually loved these questions: finally general questions allowing ideas to be expressed, instead of the common boring technicalities.

- to “pupplesan”: I think what you do in your post about the “hard problem of consciousness is not characterising it, but rather anticipating a possible answer. Which might be right. Or not.

- to “Strangelove”: Yes, Archimedes and Eudoxus are also giants. Establishing ranking is not of much interest, I think. I had the misfortune that my US publisher chose the title “The First Scientist” for my book on Anaximander, raising a silly priority debate. I meant bringing attention to Anaximander’s wonderful achievements, not to open an empty discussions about who is greatest or the first! More on the substance of your post, I agree that the key is being testable, which is the main thing you say. But I think that the picture of science as “random guesses” then tested is not a good picture. The “guesses” that have a good chance of being later confirmed are those that have ground. Your example about the spherical Earth is very good: there had been a long sequence of observations, arguments and rational thinking (An example in Aristotle’s ‘On the Heavens’ is the round shade of the Earth on the Moon during lunar eclipses) that provided very strong plausibility to the idea. I think that a problem of today’s theoretical physics is the difficulty of appreciating the difference between a “random guess” and a “well motivated guess”.

- to “ZoranOstric”. You ask about a way to overcome this separation. I think a good starting point could be simply physicists stoping talking philosophy down. For centuries scientists were cultured people, who knew the main philosophical ideas of the past, knew well the history of science, and were very curious about the philosophers of their own times. Yes, I do think that knowing what people in analytical philosophy do now would be useful. There are many thinker in analytical philosophy nowadays that I have found very interesting for a physics (Butterfield, Price, Earman, Norton, Dorato, van Fraassen, Bitbol, Halvorson, Brown, Wuthrich, Myrvold, Ismael, Weinstein, Sauders… just to name a few at random). An example: people talking about “other worlds existing” could usefully read John Austin and David Lewis, at least to avoid using “exist” so superficially…

- to “cshbar”, who asks: ‘how [my] favored theory can be falsified?’ Good question. Thanks. Answers in several steps:(i) In principle, Loop Quantum Gravity gives specific quantitative predictions, for instance regarding the possible values of the area of any surface, or cross section. Any measurement of a cross section that does not enter the set of the values predicted by theory falsifies the theory. (ii) These predictions are pretty general, and the situation is very different from string theory, which has zillions of vacua each with a different set of predictions, or multiuniverses, where it is not even very clear what a ‘prediction’ is going to be.(iii) In practice, it is difficult to test predictions, because the Planck length is small.(iv) But the claim of LQG is simple, and low key: it is not a theory we try to sell as the final theory of everything that everybody should buy; we present it is a tentative theory whose physical viability we ourselves we are far from sure about, until some empirical support comes in.(v) As for myself, predictions and testing the theory is what I am consider interesting and what I am working on. This is why I am trying to use the theory to compute the probability of black holes tunnelling into white holes, with the hope to see signals of this process in cosmic rays, and get hard testing. So, the short answer is: LQG is developed with the idea that what cannot be tested empirically is not good science.

Post-postscript: Biologist Jerry Coyne comments on the Q&A at “Why Evolution Is True,” http://whyevolutionistrue.wordpress.com/2014/08/23/accommodationism-from-a-physicist/.

John Horgan About the Author: Every week, hockey-playing science writer John Horgan takes a puckish, provocative look at breaking science. A teacher at Stevens Institute of Technology, Horgan is the author of four books, including The End of Science (Addison Wesley, 1996) and The End of War (McSweeney's, 2012). Follow on Twitter @Horganism.

The views expressed are those of the author and are not necessarily those of Scientific American.





Rights & Permissions

Comments 33 Comments

Add Comment
  1. 1. Von Stupidtz 7:26 pm 08/21/2014

    I scoff at the amount of your wager. So does James Bond,Felix Leiter,Rene Mathis and Le Chiffre.

    Link to this
  2. 2. lakefield 9:08 pm 08/21/2014

    Rovelli seems like a very level headed physicist. A breath of fresh air. On the other hand, Horgan does journalism, Scientific American and Scientific American readers no honour by asking trivial and trite questions when he has the opportunity to pose intelligent questions to someone who has really thought deeply about these ideas.

    Link to this
  3. 3. pupplesan 11:21 pm 08/21/2014

    Rovelli seems to overlook the “hard problem of consciousness” in his response to a question above. The hard problem is hard because it is unscientific and therefore inaccessible to any instrument but the private mind alone and unaided. It is perhaps the most important human problem of all but it simply cannot be probed from the outside and any attempt to deny it can be rebutted with solipsism which is arrogant but irrebuttable.

    Link to this
  4. 4. Dr. Strangelove 3:11 am 08/22/2014

    Science did advance by guessing. Hypotheses are educated guesses. But scientists did not stop there. They tested their guesses with observations. In the 15th century nobody knew the world is round. But all educated men during the Renaissance men believed the world is round. It was a hypothesis until Columbus crossed the Atlantic and did not fall off the edge of the world. The problem with theoretical physicists today is their hypotheses are untestable. It is metaphysics not science.

    IMO Eudoxus and Archimedes are greater giants than Anaximander. Eudoxus is credited for formulating the first scientific theory or model. Archimedes is the first to conduct scientific experiments.

    Nobody will win that bet against Horgan because there is no Nobel Prize for metaphysics.

    Link to this
  5. 5. carlorovelli 5:14 am 08/22/2014

    A few answers from carlo rovelli:

    - to “lakefield”: I actually loved these questions: finally general questions allowing ideas to be expressed, instead of the common boring technicalities.

    - to “pupplesan”: I think what you do in your post about the “hard problem of consciousness is not characterising it, but rather anticipating a possible answer. Which might be right. Or not.

    - to “Strangelove”: Yes, Archimedes and Eudoxus are also giants. Establishing ranking is not of much interest, I think. I had the misfortune that my US publisher chose the title “The First Scientist” for my book on Anaximander, raising a silly priority debate. I meant bringing attention to Anaximander’s wonderful achievements, not to open an empty discussions about who is greatest or the first! More on the substance of your post, I agree that the key is being testable, which is the main thing you say. But I think that the picture of science as “random guesses” then tested is not a good picture. The “guesses” that have a good chance of being later confirmed are those that have ground. Your example about the spherical Earth is very good: there had been a long sequence of observations, arguments and rational thinking (An example in Aristotle’s ‘On the Heavens’ is the round shade of the Earth on the Moon during lunar eclipses) that provided very strong plausibility to the idea. I think that a problem of today’s theoretical physics is the difficulty of appreciating the difference between a “random guess” and a “well motivated guess”.

    Link to this
  6. 6. ignorantatlarge 11:30 am 08/22/2014

    to CarloRovelli thank you for jumping in. As an undergraduate philosophy student in america (studying continental work on science, including Heisenberg) I think this is all very interesting. In particular, it seems to me that the “superficial” philosophy, given by yourself as a mixture of Popper and Kuhn, neglects the deeply historical nature of philosophical discourse and ignores other parts of the discourse (especially those not written in English). It also seems that many science people are not made aware of the philosophical location of modern science within the larger tradition, and hence have a narrow field they can discuss well — Popper and Kuhn perhaps.

    I wish the ceiling on the science/philosophy discussion could be raised significantly. Too much is happening at too clumsy a level.

    What do you think?

    Regards.

    Link to this
  7. 7. ZoranOstric 1:10 pm 08/22/2014

    Dear Carlo: I just have a discussion with a group of fb friends (scientists, philosophers, science journalists) about the interview and an issue of “physics vs philosophy” in general (“Clash of cultures”, 5-milionth round :-) ).

    Can you explain a little more what you have in mind with »read philosophy, learned from philosophy«, »wrong philosophy« and »philosophical superficiality«. I.e, the interesting question is: what you think is a way to overcome this imperfection? More courses of academic philosophy for students of physics? Or another way? To read great philosophers of the pas, as Aristotle, Spinoza, Kant etc., or current “analytical philosophy”? Or maybe books relevant for philosophy, wrote by important scientists as Heisenberg, K. F. von Weisacker etc.?

    Link to this
  8. 8. cshbar 1:29 pm 08/22/2014

    What a waste. Why bother to ask “Do multiverse theories and quantum gravity theories deserve to be taken seriously if they cannot be falsified?” If you aren’t going to bother with the obvious follow up question about how his favored theory can be falsified?

    Link to this
  9. 9. Aiya-Oba 4:21 pm 08/22/2014

    Historic gem indeed!-Aiya-Oba(natural philosopher and discoverer of Nature’s absolute logic; equator of self-contradiction, eternal oneness of relative pairness, principle of included middle).

    Link to this
  10. 10. brocephus 4:28 pm 08/22/2014

    Just one question (with no agenda or expectation): Does consciousness underlie the fabric of the cosmos?

    Link to this
  11. 11. Andrei Kirilyuk 5:15 pm 08/22/2014

    It is full of self-contradictions and leaves little hope for the possibility of any further progress in science. Those quantum gravity theories are just among those “random guesses” that Rovelli (correctly) criticizes, based in addition on purely abstract mathematical structures that “must” be realised in nature because of their “mathematical beauty”. However, they are hugely incomplete, both physically and mathematically, and therefore should normally be rejected in favour of more consistent description (or at least the search for and attempts of such description). Instead of it, each of those strongly deficient and separated mathematical guesses is fixed as “the best theory we have at present”, with artificial extension of the “present” moment to infinity…

    His opinions about the possibility of “unified” and “final” kind of description are also in contradiction with both observed physical reality and formal opposition to “random guesses”. It’s evident that physically everything is unified and explicitly produced in interaction processes. Therefore if a scientific theory cannot reproduce that real unification (and empirical completeness), it cannot even pretend to objective, truly scientific description of reality. Either science is strongly limited in general, or else the unified and causally complete description does exist, but beyond the artificial limitations of “accepted” theories. By the way, those “philosophical” approaches to interpretation of reality, which are so highly appreciated by Rovelli, tended just to a unified vision from the beginning, in contrast to modern mainstream science pushing only its disrupted and abstract “random guesses” (and pretending to be the only possible one).

    The problem of modern science is that it has been transformed from the honest, objectively estimated competition between ideas/results to purely subjective competition between personalities and their huge ambitions (let alone straightforward material factors) leading inevitably to a deadlock of strongly deficient but allegedly “best” theories…

    Link to this
  12. 12. And Then What? 5:39 pm 08/22/2014

    Thought comes before all else. If I have a thought and from that thought I formulate a hypothesis which leads to my applying the “Scientific Method” to test it. Then to me both my Thought and my action are equally important, but without my original thought my actions would not have occurred so from that perspective I might give more weight to my thought than to the action that arose from it, but it could also be argued that without my actions my thought would appear to some to be meaningless musings.

    Link to this
  13. 13. And Then What? 5:58 pm 08/22/2014

    Here is a one of my thoughts: Why would we assume that Gravity exists at the Quantum Level?

    Link to this
  14. 14. And Then What? 6:24 pm 08/22/2014

    I should probably been more specific in my formulation of my thought. what I should have said was. Thought #1: “Why would we assume that “Gravitational Effects” exist at the Quantum Level?

    Link to this
  15. 15. Dr. Strangelove 6:45 am 08/23/2014

    Carlo, educated guesses are not random. Ancient Greek philosophers were good at making educated guesses like Anaximander, Pythagoreans, Democritus, etc. String theories are not random. They use advanced mathematics. Witten is the only physicist to win the Fields Medal but no Nobel Prize for string theorists. Proof that they are doing mathematics not physics.

    Link to this
  16. 16. DrBugs 8:39 am 08/23/2014

    “Do multiverse theories and quantum gravity theories deserve to be taken seriously if they cannot be falsified?”- What kind of dumbass question is that?!?
    (Does the supposition that I simultaneously exist on earth and in the center of the star Betelgeuse deserve to be taken seriously if it cannot be falsified?”)

    Link to this
  17. 17. BenJPD 9:43 am 08/23/2014

    Nice interview. I was surprisingly interested in the response to “are science and religion compatible?” I thought I’d heard every response under the sun to that question and it’s certainly not what I came here to read, but he answered well and made some interesting points about the human value of influential religion, regardless of validity. I feel that point is often overlooked in the science-religion debate. Slightly marred for me by the inclusion of “Can physics—or science in general—ever completely solve the mystery of the universe?” And “Can science attain absolute truth”. I feel like those aren’t questions anyone with an ounce of scientific knowledge would bother asking a high-level physicist, the answers Rovelli gave are pretty obvious. 100% guaranteed that he internally rolled his eyes and thought “oh come on, really?’” when he was asked those questions! Well though-out guy though, really enjoyed reading his responses.

    Link to this
  18. 18. jayjacobus 1:17 pm 08/23/2014

    Consciousness is like the rock that can be fashioned into a tool. Before consciousness there was no taste, smell, feel, sound or (believe it or not)light. The brain fashioned consciousness into the senses.

    For this reason consciousness preceded biological evolution. But I don’t know if consciousness existed before life.

    Link to this
  19. 19. BillMcHarris 3:13 pm 08/23/2014

    Very interesting commentary, along the lines of the books, “The Trouble with Physics” and “Not Even Wrong”! As an experimental nuclear chemist/physicist who became more and more of a theorist by working out the theory to explain his experimental results, I retain an experimentalist’s point of view. Thus, I have been appalled at the lack of possible falsification so prevalent in modern physics theories; this can only lead to speculation rather than real scientific progress.

    I met with this sort of thing when studying rotational bands in deformed, especially in super-deformed nuclei. Even the experimentalists were involved with speculation, for it was much, much easier — also, much sexier — to study the states within bands rather than to characterize the ground states upon which the bands were based. Thus, rife speculation and “theoritization” about the shapes of such nuclei: Twenty years ago the literature was full of descriptions of nuclei such as “watermelon-shaped with bumps at 45 degrees,” most of which have fallen by the wayside.

    True, science progresses by educated guesses, but these are generally educated guesses leading to incremental extrapolations beyond the current theories. (I know it is popular to quote ideas such as “maybe your theory isn’t wild or weird enough,” but it should be sensibly wild or weird.) Perhaps the time has come to invoke Occam’s Razor once more, and I have suggested that one way to do this is to utilize feedback and nonlinear dynamics, even chaos theory, in modern physics.

    This is not the forum to expound on such ideas, but very briefly, many of the paradoxes of quantum mechanics have parallel, more logical explanations in classical, yet nonlinear dynamics. (This is by no means a proof, but it does raise questions about the possibility of nonlinearities in quantum mechanics.) I would suggest that interested readers examine some of the winning essays in last year’s Foundational Questions Institute contest (http://fqxi.org/community/essay/winners/2013.1), especially the essays by Prof. Rovelli (“Information and Foundations of Quantum Theory) and myself (“It from Bit from It from Bit… Nature and Nonlinear Logic”). [The essays in the fqxi contests vary greatly in quality, but many are extremely insightful.]

    Finally, a word about consciousness. Recently experimentalists at Harvard succeeded in getting 1024 fundamentally “stupid” robots to act in concert to achieve a modicum of “swarm intelligence.” This raises all sorts of questions about consciousness and self-awareness, for one can draw parallels with brains, e.g., individual neurons being non-intelligent but trillions acting in concert producing intelligence! And all of this also involves feedback, nonlinear dynamics, and emergent complexity. Perhaps science is not at a theoretical standstill after all.

    Link to this
  20. 20. jayjacobus 5:06 pm 08/23/2014

    Robots act on energy. Brains convert energy to senses. So even if the result is the same, the function is different

    Link to this
  21. 21. carlorovelli 4:49 pm 08/24/2014

    to “ZoranOstric”. You ask about a way to overcome this separation. I think a good starting point could be simply physicists stoping talking philosophy down. For centuries scientists were cultured people, who knew the main philosophical ideas of the past, knew well the history of science, and were very curious about the philosophers of their own times. Yes, I do think that knowing what people in analytical philosophy do now would be useful. There are many thinker in analytical philosophy nowadays that I have found very interesting for a physics (Butterfield, Price, Earman, Norton, Dorato, van Fraassen, Bitbol, Halvorson, Brown, Wuthrich, Myrvold, Ismael, Weinstein, Sauders… just to name a few at random). An example: people talking about “other worlds existing” could usefully read John Austin and David Lewis, at least to avoid using “exist” so superficially…

    Link to this
  22. 22. rshoff2 11:10 am 08/25/2014

    Mr Rovelli – As a child and teen in the 60s and 70s I can relate to your dream of a better world through science and technology. I agree, we did indeed lose. Somewhere around the time of the Star Wars movie, science fiction along with our national psyche adopted a dark vision of the future. It was as clear as day, and extremely frustrating and discouraging. I’m pleased for you that you found your way. Please continue to enjoy your life of science and thank you for sharing your contributions.

    Link to this
  23. 23. rshoff2 12:49 pm 08/25/2014

    btw, this is my favorite statement of Carlo Rovelli in this interview:

    Rovelli: What is the “mystery of the universe”? There isn’t a “mystery of the universe.” There is an ocean of things we do not know.

    Link to this
  24. 24. rshoff2 1:00 pm 08/25/2014

    I’m sorry for yet another comment. But I wonder. Is the brain function that endows a capability for philosophical thought also a function that enhances the ability to conceptually understand the mechanisms of physics and therefore ‘connect the dots’ that are otherwise out of reach?

    So I’m suggesting that it may not be that the ‘practice’ of philosophy endows a scientist with a great scientific mind, but the ‘capacity’ for philosophy that does.

    Link to this
  25. 25. carlorovelli 5:46 pm 08/25/2014

    to “cshbar”, who asks: ‘how [my] favored theory can be falsified?’
    Good question. Thanks. Answers in several steps:
    (i) In principle, Loop Quantum Gravity gives specific quantitative predictions, for instance regarding the possible values of the area of any surface, or cross section. Any measurement of a cross section that does not enter the set of the values predicted by theory falsifies the theory.
    (ii) These predictions are pretty general, and the situation is very different from string theory, which has zillions of vacua each with a different set of predictions, or multiuniverses, where it is not even very clear what a ‘prediction’ is going to be.
    (iii) In practice, it is difficult to test predictions, because the Planck length is small.
    (iv) But the claim of LQG is simple, and low key: it is not a theory we try to sell as the final theory of everything that everybody should buy; we present it is a tentative theory whose physical viability we ourselves we are far from sure about, until some empirical support comes in.
    (v) As for myself, predictions and testing the theory is what I am consider interesting and what I am working on. This is why I am trying to use the theory to compute the probability of black holes tunnelling into white holes, with the hope to see signals of this process in cosmic rays, and get hard testing.
    So, the short answer is: LQG is developed with the idea that what cannot be tested empirically is not good science.

    Link to this
  26. 26. economagic 11:23 am 08/26/2014

    This is one of the most thoughtful essays I have seen lately (yes, I realize it is an interview), on a par with those of journalism professor Robert Jensen in a parallel universe (sorry!). I think the professor’s points are all well taken, and his comprehension of disparate fields of study remarkable in this day and age. I hope we will hear more from him as a genuine “public intellectual.”

    I think some of Horgan’s softball questions may have stemmed from the often uneven knowledge of the readers of this blog and the magazine that supports it. Most of the comments here are distinctly better informed and more thoughtful than many I see on the various SciAm blogs and articles.

    Link to this
  27. 27. JohnDuffield 9:24 am 08/27/2014

    Nice interview. I remember Carlo’s “Forget time” essay http://arxiv.org/abs/0903.3832 but rather think the problem is that people won’t. We live in a world of space and motion, a clock measures some kind of regular cyclical motion, not the literal flow of time. When you appreciate this you understand that when an optical clock goes slower, it’s because light goes slower. And that curved spacetime is actually a curved plot of inhomogeneous space whilst electromagnetism is all about curved space. But nobody seems to know about Percy Hammond and electromagnetic geometry, or the way Einstein described a field as a state of space. Nobody seems to appreciate that the electron has one field. Or that Fμv interactions result in linear and/or rotational force. Or that when you stop the current in the wires, there’s still a force there.

    Link to this
  28. 28. daedlanth 11:08 am 08/29/2014

    rschoff2 wrote “Mr Rovelli – As a child and teen in the 60s and 70s I can relate to your dream of a better world through science and technology. I agree, we did indeed lose.”

    A holistic approach to science & society seems to be slipping away. I believe that which is, is nothing more than everything that is probable, floating in a sea of chaos. There is no room for reconciliation when all one sees is an empire to be built of nothing but stones. A little bit of everything…

    Completely understanding the universe is like the meteorological problem; we would need a perfect sensor on everything right down to the smallest scale to accurately describe what’s going on at any given time. Impossible.

    What is possible is unchaining our fellow man so that we can see the future. The alternative is to be fossilized & vaporized by Sol.

    No matter how meaningless my meandering is to you, it is part of the human condition; it deserves respect as sentience in our remarkable manifestation.

    Long live philosophy,
    daed the palindrome

    Link to this
  29. 29. Siofgon 9:16 pm 08/30/2014

    Just another Jesuit looking down at everyone else because he can read old Greek.

    I call BS.

    Link to this
  30. 30. GregRobert 1:27 pm 09/2/2014

    Well, I agree with a great deal of what you said. But not the part that seems to leave religion “off the hook”. Suggesting this part of human behavior has merit. I just am not ready to accept that based on the evidence I have seen.

    Especially with respect to what Muhammad called “religions of the book”.

    Too many people have died at the hand of religion, just too, too many. How many wars can you cite where religion didnt insist that “god was on their side”. That just HAS to stop.

    My answers to “do you believe in god?” are:
    Define god and define believe.
    Yes.
    No.
    Maybe.
    I’m not superstitious.
    God is just Santa Claus for grownups. (What’s the difference between god and santa? Most people eventually realize god isn’t real. Think about it. Making a list and checking it twice. To see who’s been naughty and who’s been nice. With rewards for one and punishment for the other?)

    The answer I give depends on who’s asking and what I surmise to be their intent. (it’s rarely actually a questiom. It’s the opening to an argument. Usually an evangelical one).

    I beleve there is more3 to the universe than we can see. A lot more. How can I rule out unimaginable things when human imagination is so limited? I believe something like what Einstein believed. (Asked by Swiss immigration authorities of his religion Einstein replied, “Mosaic”. LOL. Good enough for the Swiss, good enough for me.

    On the insult we call prayer god responds, “Dont you need think I’m perfect? Incapable of designing an imperfect rule? Then why do you endlessly ask and beseech me to change it, “just for you”. I should spite you. Quit your whining.

    On kneeling god says, “what are you doing on your knees? Do you think I’m so vain, so pathetic as to require praise or geing obsequious? I made you to stand proud. Get up off your knees.

    But, of course, I don’t believe any of that. Stop being superstious.

    By the way Judaism and Islam are monotheistic. Paganism and Christianity are firmly polythestic. Three gods but only one? Brooklyn bridge anyone? What Catholics and Christians call “mysteries” are their explanation for things we can’t explain and are impossible and that’s our story and we’re stickin’ with it.

    Link to this
  31. 31. charles000 1:08 am 09/4/2014

    A search for a universal “truth” may be inherently flawed because the universe itself and the myriad process dynamics therein are in a perpetual state of evolutionary morphology . . . like trying to pinpoint a precisely stationary target on a perpetually changing operational cosmological ecosystem.

    Link to this
  32. 32. David Brown 8:46 am 09/4/2014

    Can loop quantum gravity explain the space roar and/or the photon underproduction crisis?
    space roar
    photon underproduction crisis

    Link to this
  33. 33. solangeferreira 5:25 pm 09/23/2014

    I am really into science, really crazy about it and reading all Scientific American articles. I get so enthusiastic that every magazine I buy my heart rate speeds up, true, believe me. I Am the most christian believer ever, Christ is my life, my all, my everything…so you are very, very wrong about christians and science. I am from Brazil.

    Link to this

Add a Comment
You must sign in or register as a ScientificAmerican.com member to submit a comment.

More from Scientific American

Scientific American Holiday Sale

Black Friday/Cyber Monday Blow-Out Sale

Enter code:
HOLIDAY 2014
at checkout

Get 20% off now! >

X

Email this Article

X