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A Conversation With Sir Roger Penrose

Dr. Craig talks about his recent one-on-one conversations with the renowned mathematician and physicist.


KEVIN HARRIS: Sir Roger Penrose. Now, that is a name that has come up in our podcasts quite a bit, Dr. Craig. You had a chance to speak with him on your English speaking tour, as well as being on a radio program with him from our friend Justin Brierley of Unbelievable.

DR. CRAIG: Yes, we had about an hour and a half on the air together. This radio program still hasn’t aired yet. I think it will probably be released very soon.

KEVIN HARRIS: What was it like for you to meet with a man that you have studied for quite some time in your own work?

DR. CRAIG: I found him to be very warm and congenial. He is a very slight man; short, quite thin. I think he is in his 80s now and so somewhat frail. His eyesight is going. They asked us to sign a release form, and I was struck that he held it right up to his nose in an attempt to see where to sign his name. They helped him to do so. I wondered how in the world did he get to the studio, and then I was told they hired a car and fetched him from Oxford University and brought him to the studio in London. So, sadly, he is extremely poorly sighted now and has difficulty with his eyes. He is very friendly.

KEVIN HARRIS: For those who may not be familiar with Roger Penrose, what is his claim to fame and great contribution?

DR. CRAIG: Several. One of the most famous would be his collaboration with Stephen Hawking to develop the singularity theorems that bear their name – the Hawking-Penrose singularity theorems – which show that the prediction of an initial beginning point of the universe at which space, time, matter, and energy came into existence was not merely a feature of an ideal, unrealistic model, but in fact was a feature of any universe governed by the equations of the general theory of relativity.

KEVIN HARRIS: I imagine that one of the things that you would take advantage of (rather than send him an email and maybe get a reply back) is that you could just ask him a couple of questions for points of clarification.

DR. CRAIG: Yes, we had a very good conversation together. It was, as I say, just very conversational as we talked about these things. I’ve read enough of his work to understand something of his metaphysical worldview. What I wanted to do was to engage him in such a way as to show what theism would have to offer in answering some of the deepest questions that he himself has. One of the most remarkable and noticeable differences between Penrose and Hawking is that whereas Hawking was an old-line verificationist and positivist who said that philosophy is dead and that scientists have taken the mantle of the philosophers in answering life’s questions, Penrose is deeply philosophical and deeply interested in profound metaphysical issues. It is night and day between Penrose and Hawking with respect to their attitudes towards metaphysics. What I wanted to show him was that theism has something to offer him for the coherence of his own worldview.

KEVIN HARRIS: Does he self-describe as an agnostic? Have you gotten a bead on where he is?

DR. CRAIG: Yes, he does self-described as an agnostic. He's not an atheist. He just doesn't know. But I do think that his metaphysical worldview is, as I say, very amenable to theism.


DR. CRAIG: He believes that reality is composed of three parts or aspects. One would be the mathematical realm – this would be the realm of abstract objects studied by mathematicians. The other realm is the physical realm – this is the world studied by astrophysics (the universe of space and time, matter and energy). The third realm is the realm of the mind or the mental. He resists the tendency of modern materialism to try to collapse the realm of the mind or the mental to the physical. He is not a physicalist. So he has these three independent and unconnected realms of reality, and he doesn't know how to put them together. Why is it that the mathematical realm describes the physical realm? Why is it that the mental realm can exert physical effects in the physical universe? And how does the mental realm grasp the abstract realm of mathematical objects? He has no answers for these questions.

KEVIN HARRIS: He really is philosophical!

DR. CRAIG: He is! This is very, very deep metaphysics. He says these are the mysteries of existence that bother him. What I wanted to show him was that if he would adopt theism this would answer these mysteries about how these three realms relate. What I argued was if you have an omniscient mind – an infinite mind – then the mathematical realm of abstract objects could be conceived to be the ideas or the thoughts of this infinite mind. And the infinite mind could be the creator of the physical realm. So both of the other two realms – the abstract and the physical – are grounded in the mental. That will solve the ancient problem of the one and the many – namely, what is the source of unity beneath the diversity that we perceive in the world. He has these three diverse, independent realms that cannot be explained in terms of each other, but what the theist can do is to say priority goes to the mental and the mathematical abstract realm is the concepts and ideas or thoughts of the mental and the physical world is the creation of the mental. He was very intrigued by this idea and didn't know quite how to respond to it.

KEVIN HARRIS: What is his view of the beginning? Does he have his own model?

DR. CRAIG: He does. He has something called the cyclic conformal cosmology or CCC for short. It’s a very, very strange view that has not generated much of a following. It involves saying that the final state of an expanding universe as it expands to infinity is the same state as the beginning of a new Big Bang universe. Now this seems absurd because the one is infinitely large and the other infinitely small, and to make them identical require some fancy mathematical legerdemain on his part as well as some revisionary physics. He requires that all of the entropy generated by black holes is going to go away, and he requires that electrons have to lose their mass even though according to physics the mass of the electron is a conserved quantity that cannot be lost. So, as my friend Jim Sinclair has said, he's alienated the cosmologists by saying that entropy goes away and he's alienated the particle physicists by saying that the mass of the electron goes away. So it's a very maverick and revisionary cosmology that I suspect is really just a mathematical model that doesn't correspond to reality. It's important to understand that a physical theory like that can be very useful. It can be a good heuristic device for raising new questions and exploring new avenues that can be scientifically fruitful. It doesn't need to be a realistic model of the universe in order to be scientifically fruitful. I suspect that's what it is. But Penrose himself, as is clear in this interview, is adamant that this is a realistic (or it's at least intended to be a realistic) physical model of the universe in which we live.

KEVIN HARRIS: You had a chance to ask him about his view on the decay of the electron. Is that what he believed?

DR. CRAIG: This is what I thought his model required. As long as the electron exists it would serve as a clock in the model, and that would eliminate the possibility of regarding the end of time as the same thing as the beginning of time. You’ve got to get rid of time somehow. He explained in the interview that he does this not by making the electron go away and losing its charge or making the electron decay, he has the electron lose its mass which is, again, a revisionary element in his physics.

KEVIN HARRIS: But he doesn't hold to any kind of Big Bang model?

DR. CRAIG: Only in the sense that he does believe in an expanding universe, but he wants to make the beginning of one expanding universe the terminus of another which I think makes no metaphysical sense because if you have a universe that is expanding infinitely toward the future and infinitely large then it is not as though anything can come after it. This would be like Buzz Lightyear – “to infinity and beyond!” He would be postulating something beyond infinity. You can do that mathematically. For example, you can have a set of numbers 1, 2, 3, and so on to infinity, comma, followed by another series of numbers 1, 2, 3, and so on. But there's no way to have a causal connection between those two infinite series because there is no terminus to the first series to cause the first member of the second series. And so Penrose, to make the model work, has to get rid of time and space. And, as I say, he has various mathematical tricks that then will enable him to do this so that he can have one universe following on after another even though the universe is expanding to infinity.

KEVIN HARRIS: Has he written or said much to your knowledge on the multiverse theory?

DR. CRAIG: Yes, he has formulated, I think, the most devastating argument against using the multiverse to explain away the fine-tuning of the universe, and I've used this frequently in my talks and debates. What he points out is that if we were just a random member of a multiverse then it is incomprehensibly more probable that we should be observing just a little patch of order surrounded by a sea of chaos rather than a massively finely tuned universe like ours. Because in order for us to exist all you need is that little patch – you don't need this massive fine-tuned universe. So the idea that the only observable universes are fine-tuned universes like ours is simply false, and without that assumption the whole appeal to the multiverse is, as he puts it, worse than useless. So this is a really, really powerful argument against using the multiverse to explain away fine-tuning.

KEVIN HARRIS: Justin Brierley does a really good job on his interviews and really prepares. He is familiar with a range of topics. What are some of the things that he had the two of you discuss?

DR. CRAIG: Primarily the things that we just mentioned. First, our metaphysical worldviews – these three realms of reality and how theism might contribute to that. Second, the conformal cyclic cosmology – Penrose’s model. And then the fine-tuning of the universe and the need for a cosmic designer.

KEVIN HARRIS: We look forward to that coming out so that we can see it.

DR. CRAIG: Very good.[1]



                  [1]          Total Running Time: 14:43 (Copyright © 2019 William Lane Craig)