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The End of the Discovery of Physics

November 02, 2014     Time: 20:08
The End of the Discovery of Physics


Dr. Craig comments on an interview with George Ellis in Scientific American in which Ellis declares we may have reached the end of what we can discover in physics

Transcript The End of the Discovery of Physics


Kevin Harris: Dr. Craig, from time to time we will look at publications like Scientific American. This one has an article that mentions several people that you’ve debated. It is on physicist George Ellis titled “Physicist George Ellis Knocks Physicist For Knocking Philosophy, Falsification, Free Will.”[1] George Ellis is one of the preeminent physicists.

Dr. Craig: He is a professor of astrophysics at University of Cape Town in South Africa. He is a brilliant cosmologist. When I was speaking at Illinois Wesleyan University several years ago, I met Tony Rothman who is himself a cosmologist, and he referred to Ellis as the man who knows more about cosmology than any other man alive.

Kevin Harris: Really?

Dr. Craig: Now that is a remarkable statement when you consider the great cosmologists that exist today – people like Hawking and Isham and others. George Ellis is right at the top of the list. The thing I like about Ellis is that he is not simply a fine scientist but he is also quite philosophically sophisticated and is sensitive to philosophical distinctions and the importance of reflecting philosophically on issues of science and religion. I had the privilege of participating in a conference with him in South Africa. I was invited to a conference of all things on galaxy morphology by the South African astronomer David Block. I was offered the opportunity to give a paper upon God and the beginning of the universe. My commentator was George Ellis. You can imagine how intimidated I felt at that! Ellis not only confirmed what I had said scientifically, but went on to offer moral and philosophical arguments for theism in response to my paper. So it was a wonderful experience and I enjoyed getting to know him personally and chatting at the conference as well. I was very pleased when I saw this interview appear in Scientific American.

Kevin Harris: This article is kind of wrapped up in the caption on his photo where he says, “You cannot do physics or cosmology without an assumed philosophical basis.”

Dr. Craig: Isn’t that remarkable?

Kevin Harris: I am looking at this article online here, Dr. Craig, if you’ll take a look. The first question that he is asked is,

You were in a session called “The end of experiment.” What was that about?

Dr. Craig: This is really an interesting feature of Ellis’ thought. He believes that we have probably reached the limits of physics, of what we will ever be able to know about the fundamental physical structure of the universe. He says,

. . . many of the possible high-energy physics experiments and astronomy observations relevant to cosmology are now in essence nearly complete. Physics experiments are approaching the highest energies it will ever be possible to test by any collider experiment, both for financial and technical reasons. We can’t build a collider bigger than the surface of the Earth. Thus our ability to test high energy physics – and hence structures on the smallest physical scales – is approaching its limits. Astronomical observations at all wavelengths are now probing the most distant cosmological events that will ever be “seeable” by any kinds of radiation whatever, because of visual horizons for each form of radiation.

So he is saying that in high-energy physics and in astronomy we have now reached the limits of what we can discover about the universe. We can’t build colliders that would have higher energies to probe more deeply into the subatomic structures of reality. We can’t see any further out in the universe than we do because you get so far back close to the Big Bang that the universe then becomes opaque and you can’t see beyond that horizon. It is like a horizon that surrounds us. So he is saying that physics has pretty much reached the limits that it will ever have. This is really amazing because this is what physicists thought at the end of the 19th century. They thought that physics was then nearly complete. We’ve got the story now of the way reality is. Then came relativity theory and quantum theory and upset the whole apple cart. What Ellis is saying is that the situation now is quite different than at the end of the 19th century.[2] There they simply thought that they knew everything. He is saying what is the situation now is that we’ve reached the limits that are humanly possible for having any higher energy experiments or for probing more deeply into outer space. He is saying that there is a kind of in-principle reason for thinking that we’ve pretty much got the full physical story. That is really remarkable.

Kevin Harris: You don’t hear that very often.

Dr. Craig: No! No! It is astonishing! It is highly significant, I think, because what do skeptics so often say when confronted with evidence for the beginning of the universe or the fine-tuning of the universe? They say, “Future scientific discoveries will explain this.” They appeal to a naturalism-of-the-gaps and say just because we haven’t answered it yet, someday physics will explain the origin of the universe or the fine-tuning. I think what Ellis is implying is that that is not going to happen. He thinks that we have pretty much reached the limits, and therefore the worldview that contemporary science delivers to us right now is fundamentally correct. The rest will simply be ironing out the details. That means you can’t escape things like the finitude of the past or the fine-tuning of the universe by just punting to the future discoveries of science.

Kevin Harris: In ironing out those scientific and physical details we are also free to iron out the implications of what all that means – the philosophical implications.

Dr. Craig: It would be different than ironing. The ironing out the details is simply fleshing out more fully the theories and the description of the world, but drawing philosophical implications is, I think, what you mean. Certainly I think that the philosopher who reflects upon the data of science is free to draw the philosophical implications that these would suggest.

Kevin Harris: Several paragraphs down he is asked about Lawrence Krauss. The interviewer asks:

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 said,

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.

He lists a whole bunch of things there, Bill, that Lawrence Krauss calls “nothing.”

Dr. Craig: Yes, that is right, and he explains that these are physical systems. It is just an excoriating critique.

Kevin Harris: It really is. He says,

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.

Ellis continues,

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 . . .

Dr. Craig: Yes, isn’t that remarkable? Here he is advocating that those who are educated as scientists need to have studied Plato, Aristotle, Kant, Hume, and the other great philosophers, as well as contemporary philosophers of science. You can imagine how I resonate with what he says here when he thinks that scientists need to have training in philosophy. What a different attitude from the attitude expressed by Krauss or by Hawking and Mlodinow where they say that philosophy studies nothing and that philosophy is dead. I think Ellis quite rightly understands the vacuity of those sorts of claims.

Kevin Harris: Yeah. He says go back and study Plato, Aristotle, Kant, Hume, and then read recent philosophers like Tim Maudlin and David Albert.[3] He is then asked, “Are you, or were you ever, a believer in a final theory of physics?” Ellis said, “I certainly have believed in it as a possibility.” What are we talking about here, Dr. Craig?

Dr. Craig: He is talking here about whether there is an ultimate theory of everything that would integrate all of the fundamental forces of nature. He expresses a certain skepticism about whether this may be done. He says it may be that we wind up with two different intermeshed theories that ultimately can’t be unified. He says in the interview, “Indeed it is in my view unlikely there is a unified theory of all fundamental forces.” So this is very interesting that he thinks there may not be such a thing to be found.

Kevin Harris: He is asked, “Are you a fan of multiverse theories? String theory? The anthropic principle?”

Dr. Craig: His answer to this comes in three parts. This is a written interview, not an oral interview. So you need to tease apart the answers to these three questions successively.

The first question, “Are you a fan of multiverse theories,” he answers no, he is not a fan of multiverse theories. Why? He says it “may be true but unproveable.” That is the first problem – there could be a multiverse but it is unproveable that there is. Then he says there is “much too much untestable speculation about existence of infinities of entities.” Ellis has expressed this elsewhere. It is very interesting. He is quite skeptical about things that postulate actual infinites like an actual infinite number of universes. He is skeptical that there is such a thing as these actual infinities of entities. Then he says it involves, “ill defined and untestable probability measures.” I think there he is probably thinking of, with respect to trying to explain away fine-tuning, people like Sean Carroll who think that by having a multiverse of worlds you can manipulate the probability measures in such a way that it turns out that it is more probable we would have intelligent interactive observers like us rather than Boltzmann Brains. I think Ellis is rightly skeptical about this. He calls this “ill defined and untestable probability measures.” So for those three reasons he is not a fan of multiverse theories. It is unprovable, too much untestable speculation about infinities, and the probability measures that are appealed to are ill defined and untestable.

The second question, you will recall, was, “Are you a fan of string theory?” This is the notion that instead of fundamental particles like quarks there would be these little one-dimensional strings of energy which vibrate and thereby result in the existence of particles. He again says no. He is not a fan of string theory. He says, “too much speculative introduction of very complex unseeable entities.” So, again, he treats it as just untestable speculation. He also doesn’t like that it “treats gravity just like any other force.” As we saw a moment ago, he thinks that gravity may not be capable of being unified with the other forces of nature.

Finally was “are you a fan of the anthropic principle?” And he says yes. Here his answer needs to be carefully understood. He says,

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.

That makes it evident that by the anthropic principle, what Ellis means is the debate over the fine-tuning of the universe – that the universe is fine-tuned for our existence, and this cries out for some sort of explanation. He is a fan of that. He thinks that this is a serious problem that leads to interesting results. He is not a fan of the anthropic principle in the sense that the multiverse theorist uses it to say somewhere in the infinite ensemble of worlds there would be interactive intelligent observers, so we ought not to be surprised at observing such a world. That he has already rejected in rejecting the multiverse. But the fine-tuning remains for him a serious question that deserves exploration.

Kevin Harris: Very interesting.[4]

Dr. Craig: It is extremely interesting, isn’t it?

Kevin Harris: He is asked,

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

As we get to his answer, let’s talk a little bit about falsifiability.

Dr. Craig: As he uses it, he is not talking about a principle of meaning, the way the original falsification principle was used. I think he is saying that a good scientific theory ought to be testable, basically, is what he is saying. We ought to be able to give some conditions under which we could test it by showing that it fails to yield the predictions, for example.

Kevin Harris: To be able to falsify it?

Dr. Craig: Yes, in a word.

Kevin Harris: Ellis says,

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.

Dr. Craig: I take it here that he is attacking speculative cosmological theories like Sean Carroll’s model that was debated in my debate with Carroll.[5]What Ellis is saying is that these speculative theories that are unfalsifiable and untestable really are just sort of sterile metaphysics. It is ironic because he is accusing these cosmologists really of doing pure philosophizing without any kind of scientific testability so it is not really serious science. Ellis is committed to the view that really good science needs to have some kind of testability to it. So this talk of multiverses and baby universes being spawned by a mother universe and all the rest – those are very speculative. It is just that. It is not good science, he thinks.

Kevin Harris: Finally he is asked this question – and boy has this been the topic of some of our podcasts lately:

Krauss, Stephen Hawking and Neil deGrasse Tyson have been bashing philosophy as a waste of time. Do you agree?

Ellis says,

If they really believe this they should stop indulging in low-grade philosophy in their own writings. You cannot do physics or cosmology without an assumed philosophical basis. You can choose not to think about that basis: it will still be there as an unexamined foundation of what you do. The fact you are unwilling to examine the philosophical foundations of what you do does not mean those foundations are not there; it just means they are unexamined.

Dr. Craig: Isn’t that a remarkable statement? He says these men are doing low-grade philosophy and they don’t even realize it. Those assumptions – those foundations – are still there but they are unexamined. Really a damning indictment, I think.

Kevin Harris: He is asked,

You are a Christian . . . . Does your faith have any effect on your scientific views, or vice versa?

Ellis says,

It may affect to some degree the topics I choose to tackle, but it cannot affect the science itself, which has its own logic that must be followed wherever it leads without fear or favour, within the domain of application of the relevant theories.

Dr. Craig: Right. So he is saying that, while it may guide him in what he wants to study, science itself proceeds independently of his theological convictions.

Kevin Harris: He says,

Many key aspects of life (such as ethics: what is good and what is bad, and aesthetics: what is beautiful and what is ugly) lie outside the domain of scientific inquiry (science can tell you what kind of circumstances will lead to the extinction of polar bears, or indeed of humanity; it has nothing whatever to say about whether this would be good or bad, that is not a scientific question).

Dr. Craig: He has been very emphatic in his other writings about the importance of ethical and aesthetic questions as part of a synoptic worldview, and rejects the narrow scientism that says there are no ethical or aesthetic truths to be known because they are not scientifically discoverable. So he has a view of truth and of inquiry that recognizes that science is just one part of our attempt to get at the way reality really is.[6]