Tag Archives: George Ellis

George Ellis and Joe Silk attack untestable cosmological theories in Nature

I found this Evolution News post about it, thanks to a J. Warner Wallace tweet. The article they linked is by two well-known cosmologists.

EN writes:

Here’s what George Ellis and Joe Silk say in Nature (“Scientific Method: Defend the Integrity of Physics”):

This year, debates in physics circles took a worrying turn. Faced with difficulties in applying fundamental theories to the observed Universe, some researchers called for a change in how theoretical physics is done. They began to argue — explicitly — that if a theory is sufficiently elegant and explanatory, it need not be tested experimentally, breaking with centuries of philosophical tradition of defining scientific knowledge as empirical. We disagree. As the philosopher of science Karl Popper argued: a theory must be falsifiable to be scientific. (Emphasis added.)

In particular, they chide the string theorists, multiverse advocates, inflation theorists, and purveyors of the “many worlds” interpretation of quantum mechanics.

Their concern is that the requirement for testability is being relaxed for junky theories.

Whether Ellis and Silk’s definitions of science and the scientific method are adequate is beside the point (the definition of science is a vexed question, testability is vague, and falsifiability has its flaws). What worries them is something else:

The issue of testability has been lurking for a decade. String theory and multiverse theory have been criticized in popular books and articles, including some by one of us (G.E.). In March, theorist Paul Steinhardt wrote in this journal that the theory of inflationary cosmology is no longer scientific because it is so flexible that it can accommodate any observational result. Theorist and philosopher Richard Dawid and cosmologist Sean Carroll have countered those criticisms with a philosophical case to weaken the testability requirement for fundamental physics.

Interesting that Sean Carroll, a naturalist who proposes naturalistic alternatives to the standard (theism-friendly) cosmology model (creation out of nothing), wants to weaken the testability requirement. Why do you think that is? Well, if we go by which model is testable, rather than which model is acceptable to that old-time naturalistic religion, then then the standard model (creation out of nothing) wins. That’s because we have experimental evidence for the standard model, (light element abundances, cosmic microwave background radiation, second law of thermodynamics, etc.) Carroll’s model is falsified by observations (e.g. – humans exist, not Boltzmann brains), and that’s why why he weakens the criterion of testability. If testability is what makes science, then he’s really just engaged in creative writing.

And about the multiverse in particular:

Look what they say about multiverse theory:

The multiverse is motivated by a puzzle: why fundamental constants of nature, such as the fine-structure constant that characterizes the strength of electromagnetic interactions between particles and the cosmological constant associated with the acceleration of the expansion of the Universe, have values that lie in the small range that allows life to exist. Multiverse theory claims that there are billions of unobservable sister universes out there in which all possible values of these constants can occur. So somewhere there will be a bio-friendly universe like ours, however improbable that is.

That sounds like a lead-up to The Privileged Planet, or to Privileged Species. Ellis and Silk go on to describe how one of the constants, the cosmological constant, is 120 orders of magnitude off from the predicted theoretical value. So are they ready to consider scientific theories that embrace this evidence, like intelligent design? No, but one thing they do know: multiverse theory is not scientific.

Billions of universes — and of galaxies and copies of each of us — accumulate with no possibility of communication between them or of testing their reality. But if a duplicate self exists in every multiverse domain and there are infinitely many, which is the real ‘me’ that I experience now? Is any version of oneself preferred over any other? How could ‘I’ ever know what the ‘true’ nature of reality is if one self favours the multiverse and another does not?

That’s a logical statement, not an observational one. By this, we see that they are not against using logical inference to eliminate unworthy theories. Isn’t that what Meyer does in his books, using “inference to the best explanation”? Isn’t that what Dembski does to eliminate the chance hypothesis?

In the end, Ellis and Silk never explain cosmic fine-tuning. They just preach that science needs to stick to the old-time religion: respect for observable, testable evidence.

The article by Ellis and Silk takes a lot of shots at fundamentalist religion, but at least we fundamentalists are OK with following testable science wherever it goes. Unlike naturalists.

Physicist George Ellis interviewed by science writer John Horgan in Scientific American

I’m mentioned George Ellis on this blog before, specifically on his doubts about the speculative multiverse cosmology.

Here he is interviewed in Scientific American. (H/T Think Apologetics)

Intro:

Biologist Rupert Sheldrake, whom I interviewed in my last post, wasn’t the only fascinating scientist I hung out with recently at Howthelightgetsin, a festival hosted by the Institute of Arts & Ideas. I also befriended George F. R. Ellis, the physicist-mathematician-cosmologist, an authority on the Big Bang and other cosmic mysteries. Ellis and I hit it off initially because we share some—how shall I put it?—concerns about the direction of physics, but I soon discovered that his interests range far beyond physics. He has published papers and books not only on physics and cosmology (including the 1973 classic The Large-Scale Structure of Space-Time, co-authored with Stephen Hawking) but also on philosophy, complexity theory, neuroscience, education and even low-income housing. (See his website, and his terrific 2011 critique of multiverse theories in Scientific American.) A native of South Africa, Ellis is professor emeritus at the University of Cape Town, where he taught for decades, and has also held positions at Cambridge, the University of Texas, the Fermi Institute and other institutions around the globe.

Awesome:

Horgan: Lawrence Krauss, in A Universe from Nothing, claims that physics has basically solved the mystery of why there is something rather than nothing. Do you agree?

Ellis: Certainly not.  He is presenting untested speculative theories of how things came into existence out of a pre-existing complex of entities, including variational principles, quantum field theory, specific symmetry groups, a bubbling vacuum, all the components of the standard model of particle physics, and so on. He does not explain in what way these entities could have pre-existed the coming into being of the universe, why they should have existed at all, or why they should have had the form they did.  And he gives no experimental or observational process whereby we could test these vivid speculations of the supposed universe-generation mechanism. How indeed can you test what existed before the universe existed? You can’t.

Thus what he is presenting is not tested science. It’s a philosophical speculation, which he apparently believes is so compelling he does not have to give any specification of evidence that would confirm it is true. Well, you can’t get any evidence about what existed before space and time came into being.  Above all he believes that these mathematically based speculations solve thousand year old philosophical conundrums, without seriously engaging those philosophical issues. The belief that all of reality can be fully comprehended in terms of physics and the equations of physics is a fantasy. As pointed out so well by Eddington in his Gifford lectures, they are partial and incomplete representations of physical, biological, psychological, and social reality.

And above all Krauss does not address why the laws of physics exist, why they have the form they have, or in what kind of manifestation they existed before the universe existed  (which he must believe if he believes they brought the universe into existence). Who or what dreamt up symmetry principles, Lagrangians, specific symmetry groups, gauge theories, and so on? He does not begin to answer these questions.

It’s very ironic when he says philosophy is bunk and then himself engages in this kind of attempt at philosophy. It seems that science education should include some basic modules on Plato, Aristotle, Kant, Hume, and the other great philosophers, as well as writings of more recent philosophers such as Tim Maudlin and David Albert.

He likes fine-tuning, but not multiverse and string theory:

Horgan: Are you a fan of multiverse theories? String theory? The anthropic principle?

No (may be true but unproveable, much too much untestable speculation about existence of infinities of entities, ill defined and untestable probability measures), no (too much speculative introduction of very complex unseeable entities, treats gravity just like any other force), yes (however one responds to it, it’s a real question that deserves consideration).  Fine tuning of fundamental physics parameters is required in order that we can exist. Examining this issue has led to many very interesting studies.

Horgan: Physicist Sean Carroll has argued that falsifiability is overrated as a criterion for judging whether theories should be taken seriously. Do you agree?

Ellis: This is a major step backwards to before the evidence-based scientific revolution initiated by Galileo and Newton.  The basic idea is that our speculative theories, extrapolating into the unknown and into untestable areas from well-tested areas of physics, are so good they have to be true. History proves that is the path to delusion: just because you have a good theory does not prove it is true. The other defence is that there is no other game in town. But there may not be any such game.

Scientists should strongly resist such an attack on the very foundations of its own success. Luckily it is a very small subset of scientists who are making this proposal.

Free will is real:

Horgan: In some of your writings, you warn against excessive determinism in physics, and science. Could you summarize your concerns?

Many scientists are strong reductionists who believe that physics alone determines outcomes in the real world, This is demonstrably untrue – for example the computer on which I am writing this could not possibly have come into being through the agency of physics alone.

The issue is that these scientists are focusing on some strands in the web of causation that actually exist, and ignoring others that are demonstrably there – such as ideas in our minds, or algorithms embodied in computer programs. These demonstrably act in a top-down way to cause physical effects in the real world. All these processes and actual outcomes are contextually dependent, and this allows the effectiveness of processes such as adaptive selection that are the key to the emergence of genuine complexity.

As I stated above, mathematical equations only represent part of reality, and should not be confused with reality.  A specific related issue: there is a group of people out there writing papers based on the idea that physics is a computational process.  But a physical law is not an algorithm. So who chooses the computational strategy and the algorithms that realise a specific physical law? (Finite elements perhaps?) What language is it written in? (Does Nature use Java or C++? What machine code is used?) Where is the CPU? What is used for memory, and in what way are read and write commands executed? Additionally if it’s a computation, how does Nature avoid the halting problem? It’s all a very bad analogy that does not work.

Horgan: Einstein, in the following quote, seemed to doubt free will: “If the moon, in the act of completing its eternal way around the Earth, were gifted with self-consciousness, it would feel thoroughly convinced that it was traveling its way of its own accord…. So would a Being, endowed with higher insight and more perfect intelligence, watching man and his doings, smile about man’s illusion that he was acting according to his own free will.” Do you believe in free will?

Ellis: Yes. Einstein is perpetuating the belief that all causation is bottom up. This simply is not the case, as I can demonstrate with many examples from sociology, neuroscience, physiology, epigenetics, engineering, and physics.  Furthermore if Einstein did not have free will in some meaningful sense, then he could not have been responsible for the theory of relativity – it would have been a product of lower level processes but not of an intelligent mind choosing between possible options.

I find it very hard to believe this to be the case – indeed it does not seem to make any sense. Physicists should pay attention to Aristotle’s four forms of causation – if they have the free will to decide what they are doing. If they don’t, then why waste time talking to them? They are then not responsible for what they say.

Sometimes, you have to just point out that a speculation is a speculation, and that we do not prefer speculations over experimental results. The data we have is consistent with an origin of the universe out of nothing, and the best explanation of this effect is a supernatural cause. Period.

Why do atheists believe in unobservable entities and weird things?

Consider this summary of an article in Nature written by George Ellis, a famous cosmologist based in Cape Town, South Africa.

Excerpt:

Multiverse thinking or the belief in the existence of parallel universes is more philosophy or science fiction than science. ”Cosmology must seem odd to scientists in other fields”.

George Ellis, a well-known mathematician and cosmologist, who for instance has written a book with Stephen Hawking, is sceptical of the idea that our universe is just another universe among many others.

A few weeks ago, Ellis, professor emeritus of applied mathematics at the University of Cape Town, reviewed Brian Greene’s book The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos (Knopf/Allen Lane, 2011) in the journal Nature. He is not at all convinced that the multiverse hypothesis is credible: ”Greene is not presenting aspects of a known reality; he is telling of unproven theoretical possibilities.”

According to professor Ellis, there is no evidence of multiverses, they cannot be tested and they are not science.

Ellis is not the only multiverse sceptic in this universe. A few months ago, science writer John Horgan wrote a column in Scientific American, expressing his doubt in multiverses.

Multiverse thinking is basically an atheistic attempt to solve some huge problems with the big bang and explain why the universe could have been formed without a design or a Designer.

Now how do the theorteical physicists respond to this?

Here’s an article from Scientific American responding to Ellis. (H/T Uncommon Descent)

Excerpt:

This picture of the universe, or multiverse, as it is called, explains the long-standing mystery of why the constants of nature appear to be fine-tuned for the emergence of life. The reason is that intelligent observers exist only in those rare bubbles in which, by pure chance, the constants happen to be just right for life to evolve. The rest of the multiverse remains barren, but no one is there to complain about that.

Some of my physicist colleagues find the multiverse theory alarming. Any theory in physics stands or falls depending on whether its predictions agree with the data. But how can we verify the existence of other bubble universes? Paul Steinhardt and George Ellis have argued, for example, that the multiverse theory is unscientific, because it cannot be tested, even in principle.

[…]Our universe appears surprisingly fine-tuned for life in the sense that if you tweaked many of our constants of nature by just a tiny amount, life as we know it would be impossible. Why? If there’s a Level II multiverse where these “constants” take all possible values, it’s not surprising that we find ourselves in one of the rare universes that are inhabitable, just like it’s not surprising that we find ourselves living on Earth rather than Mercury or Neptune.

[…]George argues that if we take seriously that anything that could happen does happen, we’re led down a slippery slope toward even larger multiverses, like the Level IV one. Since this is my favorite multiverse level, and I’m one of the very few proponents of it, this is a slope that I’m happy to slide down!

Is the multiverse theory a good response to the fine-tuning argument? It seems to me that the fine-tuning rests on solid experimental evidence, while the multiverse rests on what-if speculations about unobservable entities.