Episode 4The fine tuning of the Universe: Was the cosmos made for us?

Episode Transcript:

JB: Justin Brierley
SH: Sabina Hossenfelder
LB: Luke Barnes

JB: Hello and welcome along to the Big Conversation from Unbelievable? brought to you in partnership with the John Templeton Foundation. I’m Justin Brierley. And the Big Conversation is all about exploring the biggest questions of science, faith and philosophy, with some of the leading thinkers from the religious and non religious world. Today we’re talking about the fine tuning of the universe; was the cosmos created for us? This season is being recorded remotely for obvious reasons, but the silver-lining is that it does allow us to bring fascinating voices together from around the world. And joining me today are Luke Barnes and Sabina Hossenfelder.

Luke Barnes is an Astrophysicist researching galaxy formation and dark energy at Western Sydney University. He’s a co-author of books including A Fortunate Universe: Life in a Finely Tuned Cosmos, and believes that fine tuning provides evidence that life was indeed intended by a creator. Sabina Hossenfelder is a theoretical physicist researching dark matter at the Frankfurt Institute for Advanced Studies. And she’s the author of Lost in Math: How Beauty Leads Physics Astray. She doesn’t believe the universe is fine tuned for life or that God’s existence can be hypothesised from science. Such a treat to have you both on the programme with me today, Sabina, and Luke, thank you for joining me. Let’s start with you, Sabina.

How did you get involved in this particular area of science and tell us a little bit about your interests? Because you don’t only produce great videos on your YouTube channel explaining scientific concepts you even do music videos and things. So tell us a little about yourself first of all.

SH: Yeah, so how did I get into this? I originally studied mathematics. And it turned out I was more interested by the question; How much can we learn from mathematics about the world? Than by figuring out exactly, you know, how mathematical structures themselves to behave. So naturally, I ended up being in physics, mostly in the foundations of physics. Researching this question, how much can we learn about the world using mathematics and I worked for a little bit on quantum gravity, high-energy particle physics. Now I do more Astro physics, as you just said, I also do a little bit foundations of quantum mechanics. So all that kind of stuff, where mathematics is really the whole game, basically. And, yeah, I mean, I have a lot of interests related to this, I have an interest in the philosophy of physics is kind of very close by this whole research area. And as you said, I you know, I guess I have a creative urge.
So every once in a while I sing.

JB: It’s fun. I’ve really enjoyed watching some of your videos. What about faith, Sabina, has belief in God or any kind of faith ever figured in your life or not really?

SH: Well, so I’ve grown up in Germany, and most people here are Christian, either a Roman Catholic or a Protestant. My husband’s whole family is Catholic.
But I’ve I’ve grown up as an atheist. And I’ve also never been christianized. And I, for some while I considered attending church so I attended mass for some time, and I liked the singing, but I couldn’t really identify with it. So I would say that, for what my professional scientist is concerned, I would identify as agnostic. I don’t really have an opinion about it either way. But if you ask about the way that I live my life in practice, I don’t belong to any religion, and I don’t attend church.

JB: Sure. When you when you look at the night sky, or some of the extraordinary things about our universe, does it ever inspire anything like religious awe in you or would you describe it a different way?

SH: I would say I don’t really know what you’re talking about. So I guess that means the answer is no. I mean, I find it totally amazing. You know, I like to think about what’s going on out there. And it always blows my mind, you know, if you try to imagine the, the size of the cosmos and all the stuff that’s in there, but I don’t associate anything religious with it.

JB: Okay, well, maybe we’ll return to some of those sorts of questions later on in the show, but I’m really looking forward to unpacking some of the science behind this as well. And with Luke, of course, or other guests on the show today, Luke bit of background to yourself, how did you end up researching dark matter and multiverses and all the interesting stuff you do and of course, the fine tuning of the universe for life. How did you come into that particular field?

LB: Well, I mean, well, I started off more respectable astrophysicist just doing things like how galaxies form, cosmology was always an interest. I mean, I grew up as a bit of a dinosaur nerd, but again, through maths, just wanting to realise this was a way to understand the world. But I had heard about this sort of field of fine tuning books by, you know, Barrow and Tipler, and Paul Davis and a bunch of other people. And so just started reading the scientific literature on this and got fascinated in it, and then sort of realised there were ways to contribute to that field by looking at various ways that life depends on the fundamental constants of nature.

JB: Brilliant. Tell me about your own faith commitments. I mean, and do they, at any level sort of impact the science that you do?

LB: So I’m a Christian, I grew up in a Christian household, and sort of towards the end of teenage years, obviously, an interest in science. There’s a whole lot of people who, you know, were saying that, you know, these two things couldn’t be held together. So I started reading a whole bunch of stuff by atheists, there’s a whole bunch of Dawkins behind me and such. And at the end of that still had my faith, I still go to church and all those sorts of things. It inspires me to, to investigate the world, because the world’s an amazing place, and for me, and amazing creation, so. But beyond that, you know, apart from a very deep belief that the universe is ultimately a rational place.

Beyond that science, and you know, science is really just sort of the world. My Christian faith is the worldview in which I do science, rather than anything that specifically turns up by theory, I never, I never answered God on any of my physics exams.

JB: Well, it’s great to have you both on the show today. Thank you very much for joining me. Maybe we should start with an explanation of the fine tuning of the universe itself. Obviously, we’re going to try and keep this accessible for laypeople. Luke, in a way, you’re making the arguments for this phenomenon today. So why don’t you begin and explain as simply as you can, what the fine tuning of the universe for life is, and maybe with an example, or two of some of these particular constants and parameters that appear to be finely tuned for for life to develop in the cosmos.

LB: Right. So roughly, when we say fine tuned, it’s a bit like the way we use it in everyday life, it doesn’t necessarily mean a fine tuner, it just means that there’s some sort of, that an explanation requires a suspiciously precise assumption in order to work. And so specifically, when we look at the ultimate, sort of the deepest laws of nature, we currently have the standard models. There are these numbers in them. And for whatever reason, mischievousness or curiosity, we, we can think about what would happen if those numbers were different? What would happen if the if you know, there was a universe, and when you describe the universe in laws, there was the same laws as ours, but these numbers were different. And there’s, there’s numbers like the cosmological constant, which is a sort of an accelerating influence on space, or a decelerating influence on space. To put it roughly.

There’s a sort of range that this number could have in our theories between what are called the Plank limits of if we wanted to go outside of those limits, we need a quantum theory of gravity when we don’t really have a successful one of those at the moment. But within those limits, almost all the universes are kind of disastrous. So if, if it were, if the number is too large and positive, the universe expands so fast, that no structure formed, no protons ever sort of get together into nuclei or anything. If it’s too negative, then the universe re-collapses in less than a second or something. And within the total range, the limits that avoid those two sort of catastrophes is sort of one part in about, even very conservatively, 10 to the 90 at most.

We can also talk about the sort of typical scale of the particles, of the masses of the particles were made of, there’s a number called the Higgs vacuum Expectation Value, it has a certain value in our universe, it could in the equations go between zero and again, this plank limit. And on that scale, you’ve got again, you’ve got to land between the numbers are six times 10 to the minus 18. And three about three times 10 to the minus 17. So, you know, six times one over and then 18 zeros on the bottom there. These are the sorts of numbers and if you’re on one side of that range, then a free hydrogen atom can just eat its electron and turn into a neutron. So you get an pure neutron universe in which structure won’t form. And if you’re on the other side, then you can’t stick any of the fundamental bits of the universe together to make nuclei. And again, you get a pretty disastrous, kind of boring universe.

There’s also the strengths of the forces, the fine structure constant, for example, in our universe, it’s about seven over 1000. If it was 18, over 1000, then you get the neutron universe again, the proton would be heavier than the neutron, it would decay into the neutron, you wouldn’t get, you know, free hydrogen in the universe. And so these seem like pretty disastrous, things, outcomes. And in particular, it seems like the complexity that any form, conceivable form of life would need would not exist in those universes, those universes are remarkably simple. And so, you know, there’s a whole bunch of other cases, just to plug the book. There’s a whole bunch of them in here. The first author is Geraint Lewis, a colleague of mine at University of Sydney, who’s also an atheist. So we agree about the science. And then in the last chapter, we disagree about what it means. Certainly, does that make sense

JB: Yeah, that’s really helpful. And the point being here, that, that if these, you know, particular values and constants differed, even by a tiny, tiny fraction from their actual given value, we would not have a universe that could support life. Now, that’s not to say that life would necessarily develop in such a universe. But you wouldn’t have, for example, just the basic chemistry needed to enable life at some point to get going in the universe. That’s the way I understand it Luke.

LB: Yeah, roughly, it’s not that if we figure out all the possibilities, it’s not that our point is uniquely able to support life, it’s just that the bits that are able to support the complexity needed by life are very small pieces of the total. So there might be another small bit elsewhere, but they’re not, you don’t hit it. So you don’t hit him at random. But that’s sort of assuming the result. But yeah, they’re very, a very small part of the overall.

JB: Thank you very much. Okay, Sabina, let’s come to you. Because you’ve, I know, interacted with this argument before, and you’re sceptical from the very outset that there really is such a thing as the fine tuning of the universe. So tell us where you begin with all of this?

SH: Well, it starts with what Luke said at the very beginning that these types of fine tuning arguments are similar to the types of fine tuning that we observe in everyday life; they are just not. So the typical example that people like to bring up for fine tuning is a pencil balanced on its tip. So we wouldn’t normally observe that in everyday life, it’s a highly unstable situation. If we saw something like that, we would expect an explanation, you know, there’s something holding that pen in position, or whatever. So the point is that we come to this conclusion, it’s unlikely, it requires some explanation, right? But how do we know that? Well, we know that there are other positions that a pencil can be in that are much more likely. And the reason we say it’s much more likely is because we have observed many times. So we have observational evidence.

Now when we’re talking about the values of the constants in the concordance model, or the stem model of particle physics, whatever it is, like these examples, Luke was just talking about, we can’t change these constants they have one value for all we currently know, you know, that there are variations of these models, where people consider that the constants may actually vary with space and time. But that’s a different story entirely. So for the models that Luke what I was just talking about, they they are constants as the name says, and we can’t change them. There’s no physical process that will change these constants. Now, one can make a purely theoretical observation of the type that Luke was talking about, you know, as a hypothetical question, you can say, Well, what would a universe look like if I were to change this constant this way, or some other way? And lots of people have done that, and there have been books written about it, and that’s all fine with me. But it’s not a scientific claim to say there’s something in need of an explanation here, because these are not examples that we can ever observe. So we don’t know anything about the probability of that ever happening.

JB: Okay, so essentially, you’re just not convinced that we could know that these constants and values could take a different value. Therefore, we don’t know what the probability is of them taking a different value. Therefore, all we have is the one example we do have in our universe of the values they do take, which do happen to support life in the universe, I know that you’re very critical, not just of those who use fine tuning as an argument for God, but even for a multiverse which, which is a relatively popular, as I see it, principle in physics, a lot of people seem to be, you know, engaging with that idea. But but but you’re quite critical of that, aren’t you?

SH: Well, the multiverse is not a principle. It’s a hypothesis. And it’s not a scientific hypothesis. And yeah, I mean, it’s a little bit more complicated. The fine tuning argument is not the only argument that people bring up in favour of the multiverse, but it’s certainly one of them. And yeah, it’s kind of similar. So people are saying, well, we do observe these constants of nature. That’s arguably correct. And then they say, well, we want to have an explanation for that, like, Why do the values have the values that they have? And that’s fine with me, you know, that’s what science is all about. You want you want an explanation? And they say, whether the multiverse is this explanation, and that’s, that’s where my problem begins? Because it doesn’t explain anything in the in the scientific sense. It doesn’t explain anything. And why do they think it explains something is because they’ve constructed a problem, which is unscientific to begin with, which is this fine tuning argument, there’s just as you as you summarise the correctly, we can’t change these constants, therefore, we don’t know anything about the probability of that ever happening. So there’s nothing in need of an explanation.

JB: Okay, I think this will be a key difference between you here then Luke, what’s what’s your response to this idea that? Well, we don’t know that they could take a different value, therefore, we just can’t assign any probability to their being unusual in that sense.

LB: Yeah, so the the idea that the only way that you get probabilities, or that you can know probabilities is by observing a large number of things, you know, data. That’s an interpretation of probabilities known as frequent-ism, which Sabina’s, outlined in one of her videos. And it’s not, I don’t think, it’s an interpretation of probability that a lot of scientists subscribe to. The alternative is something called well, there’s a number of alternatives, but one of them is called Bayesian-ism. And I did a quick check on the NASA publication database. There are currently over 11,000 papers with the word Bayesian in the title.
There are 79 papers with the word frequentist in the title or Frequentism,and, half of those also have the word Bayesian in the title. So the whole point of trying to let me try and lay out what this word means.

For a Bayesian, you can interpret probabilities to mean degrees of support. The idea that one statement supports another statement. So there are ‘dark clouds overhead’ supports the statement that it will be raining 10 minutes from now. Now, you can also support that with data, of course, that statement is not a statement about the data we’ve already observed it’s a statement about how different propositions support each other. And once you’ve done that, I mean, the fact that you can’t run the fine tuning argument on frequentism is, yeah, of course, like every, paper on the fine tuning argument that, you know, mentions that at some point, it’s all run via what are called Why are these sort of Bayesian or epistemic probabilities, and they are widely used in physics. So there’s a major statement there that needs to be supported. I mean, there’s discussions of Bayesian ism that Sabina has brought up in her various publications. But all I’d want to say is that to say that we can’t observe other values of the constants, therefore, there’s no sense in talking about their probability. Assumes an interpretation of probability that is not shared that at the very least, there’s a vast vast number of scientists or physicists of statisticians, who, who wouldn’t sign up to that’s called finite frequent ism. And I think it’s a complete non starter,

JB: Sabina?

SH: Well, yes, of course, I’m aware that there are different ways of interpreting, interpreting probabilities.

I actually, when I made this argument, I did not say that we need to have, the only way to speak about the probabilities is to have observational evidence of these other values. There are certainly other ways that you can go about it, but in the end, they all go back to evidence like if I think of this balanced pencil again, you don’t necessary need to sample a lot of instances of pencils in one or the other orientation, you can also just use a physical theory about what you have learned about, you know, the air or the surface that it’s standing on and the kind of vibrations, distortions that can occur and you would, you would again, come to the conclusion that it’s very unlikely to observe a pencil balanced on its tip, and you can interpret this in a Bayesian way.

It’s like, it’s not the expectation, you would have on that observation. But again, that’s an argument you can’t make for the constants of nature. There are no physical processes that could change these constants of nature, because they’re constant. And if you go by the expectation that we have, from the observations that we have made, your expectation is, of course, the next time you measure, you know, alpha, it will have the same value that it had before. So again, I don’t know what you’re talking about.

JB: Luke, I mean, is there is there any, in principle reason, why these values couldn’t take a difference? I mean, are you saying that: Yes, of course, they do take the value they take in our universe. But you don’t see any reason why they couldn’t potentially be different from the values they do hold.

LB: Maybe it’ll help if we just sort of step back a bit. This is all happening in the context of some very fundamental questions about the universe. So if we’re talking about the fine tuning argument, I take the fine tuning argument to be a sort of an extension of a very basic, it’s not even an argument, it’s just kind of an instinct. You know why most people who’ve ever lived and still live believe that there’s a God? Well, one of the reasons might be if you look around at the universe, and there are various bits and pieces of it that seem to fit well together in a way that you might think, you know, needs a mind. And that’s a very sort of basic way of putting the world together and seeing if that makes sense of it. And it seems that it does make sense. But there’s, there’s various things around us that seem like that.

So the question is now what happens when science starts to, to inform the way that we actually understand the world? Well, on a, on a first level, finding that the world is more intricately put together, then our first observations show seems to strengthen that intuition. If you think a hummingbird is amazing, then zooming out and seeing the whole of an ecosystem, or looking back in time at the processes that brought the hummingbird into existence, or zooming in on the sort of the biological details of a hummingbird, all of that is just more amazing stuff. So if you want to try and make this sort of instinct, really secure, you might say, “Okay, let’s go as deep as we can, and try to work out whether the universe that we see is the sort of place that looks kind of thrown together at random, you know, Bertrand Russell saying we’re all accidental collocations of atoms, or whether there is something remarkable about the way the universe is at its most fundamental level”. And what fine tuning suggests is, there’s a systematic way of doing this; why don’t we go to the fundamental laws of nature? And when we look at those, there are these numbers that you just have to put in that, the equation doesn’t give you. Why don’t we systematically change those as much as we can and try and work out what would happen and see if there is something remarkable about the way the universe is, as opposed to ways the universe could have been? So the fact that there aren’t, that’s a counterfactual statement; things way the universe could have been. So I think in that context, what fine tuning is trying to do is trying to answer that question, is there anything remarkable about the way the universe is rather than the ways that it could have been, but isn’t. And a systematic way of looking through those is let’s change these constants. And when you do that, these other possibilities are just kind of, as best we know, possibilities. I mean, if you’ve got some idea about why it’s it’s metaphysically, necessary, or logically necessary, why the universe has to be like this, then publish it. But in the absence of that, let’s at least look at these other possibilities. See if there’s something remarkable about our universe, and into that what the Bayesian approach is giving is to say that we can take our uncertainty about why things are the way they are, and that is enough to generate a probability distribution.

Yes, I can get them from data; Frequentism. I can get them from scientific models. That’s objective chances. There’s various ways of that. That’s another interpretation probability, yes, I can get them that way. I can also get them from uncertainty, I mean, this is what probabilities is are supposed to do. The fact that you know, there is uncertainty if I just look at the world, trying to look at it and blankly and say, Okay, what are some other ways it could have been? I don’t know why it’s this way, rather than another way, that that uncertainty under certain conditions can be quantified into a probability.

JB: We’ll get your response to that in a moment’s time, Sabina. I’m just going to go to a quick break. And then I’d love to open up this question of whether you do think it’s remarkable, in any case, that the universe does happen to take the values it takes, or whether you know, the fact that we’re here to observe it, you know, just is, one of those things that couldn’t be other than it is.

We’re talking about the fine tuning of the Universe Today, here on The Big Conversation from Unbelievable?, I’m Justin Brierley, and joined today by Luke Barnes and Sabina hossenfelder.

Part 2- 26:06 on timecode

JB: Welcome back to this week’s edition of the Big Conversation from Unbelievable? I’m Justin Brierley. My guests today are Luke Barnes and Sabina hossenfelder. We’re talking about the fine tuning of the universe, was the cosmos made for us? And just in that last section, Sabina, we heard Luke describing the ways in which he believes that it is valid to look at the constants and values of the fundamental forces in the universe. And to see that they do require an explanation for why they take the value they take, that involves us. I mean, a common response to this has been something sometimes called the weak anthropic principle, as an objection to this, which is Well, look, it’s hardly surprising that we observe a universe, which has the kinds of qualities that can sustain us, because we wouldn’t be here to observe it otherwise. It’s a kind of, well what else would you expect to see? I mean, do you find that a sufficient sort of explanation for why we find ourselves in this universe that, of course, it’s going to have the values that support us, Sabina?

SH: Well, that depends very much on what you mean by sufficient explanation. Now, the the anthropic principle, I think, has been a little bit abused by some people. To me, it’s just, it’s an observational constraint on our parameters, I don’t know what’s different about the observation that we exist, like we’re here, and we’re talking, that seems like a true observation.

And that’s only possible if the constants of nature are within certain parameter ranges that allow for the existence of life. And that’s just correct. Now, when one can debate how useful this constraint is, in practice, I would say it has limited use, but it’s there’s nothing unscientific about it. Now, does that explain the values of the constants per se, not explain certain constraints on them, as I just said, but to come to your question like, is that something in need of an explanation?

Well, when it comes to purely the values of these constants, taking into account the observational constraints that we have? The answer is no. Now then you can ask is, is the other theories that we have right now? Are they a satisfactory explanation? Are they a sufficient explanation? And I think that’s just a very, you know, a very personal question. Some people would say, well, the theories that we have are sufficient, they’re fine as an explanation. And other people might go and ask for some kind of deeper explanation, maybe. And I would just say, well, that’s leaving the scientific territory.

JB: And in that sense, then, when you kind of look at your existence in the universe, you don’t think this is highly unlikely or remarkable. You just take it as a given that the universe has produced you.

SH: That’s right. I don’t think this is unlikely because I have no way to say anything about this probability.

JB: Okay. Luke, what’s your response to this particular way of saying, ‘Yeah, there isn’t an issue to be debated here. Because what else would you be expecting? You know, you’re looking at a universe that produced you, it’s bound to have the kinds of fundamental physics that allows that.’

LB: Well, I think Sabina’s point is slightly different from the the anthropic principle. Her video on this is quite good, actually, which is refreshing. There’s a whole lot of nonsense about the anthropic principle going around.

So the point the crucial point, there was that the values of these constants are not calling out for an explanation. I think there is a general case to say that they are. So if you take say, Poppers account of what’s a good criterion, say a necessary maybe sufficient, depends on who you ask, criterion for an idea to be a scientific idea? Well it’s got to be falsifiable; there’s got to be some set of observations that we could make where we’d say, all right, well, we saw this and so that idea is definitely wrong. One of the ways to avoid being falsified is to make your idea very flexible.

And so if you make an idea, very flexible, so that it can explain a whole range of things, depending on its own internal, you know, cogs and wheels, the problem is it won’t explain the data, it will simply accommodate the data. Now, free parameters in any theory, are our assumptions, those are flexibility in the theory, the Standard Model of particle physics has 25 of them. Okay, so those in and of themselves are flexibility in the theory. And if we could get behind that to a theory that removes some of that flexibility, that would be a better thing. And I don’t think there’s much disagreement with Sabina about that. But then what you would not accept is if someone said, I’ve got a better theory that explains the value of the constant, someone saying, Oh, no, I can just generate, I can just say that the constant is what it is, and there’s nothing to explain. If there’s nothing to explain, then how can there be a better explanation? That’s my confusion with Sabina’s position here.

JB: Go ahead, Sabina.

SH: So the theories that we presently use work just fine. I think we agree on that. So they definitely explained a huge lot of data, both out there in the cosmos, and when it comes to particle physics, and I yet have to see a better theory. Let me put it that way. So these theories are de facto the best explanations that we currently have. Is it possible that there are better explanations than that, from which we can maybe one day calculate several of these constants? Or they turn out to be related in some way? Certainly, you know, I don’t have an issue with that.

But there’s nothing right now, from which I would say that actually requires such an explanation. For all we presently know, these constants may just have the values that they have, period. And that’s it. And that’s just the best explanation that there is.

JB: Yeah, why does that explanation not satisfy you, then, Luke, I’m trying to get to the core of of why you think that, that we do need a better explanation than just these other constants we have? And that’s enough.

LB: Yeah. Again, it. How do I want to put this, again, I get back to Poppers point about flexible theories. So any; think about a sort of a mathematician, and they lay out the axioms of here’s where I’m going to start from, and then I’m going to try and prove some stuff. If someone could come along and say, “Okay, see your starting point, hey, I could take one of those off this list that list and still prove everything that you’ve proved”, we would go with that second simpler option. So part of what makes a better explanation is that it has fewer assumptions. Now, just counting assumptions is a bit of a rough idea. What we want to be actually more precise about that. And I think the Bayesian approach gives us that precision.

So what I want to say is that a free parameter in a theory is a degree of flexibility that a deeper theory might not have. And in that case, the deeper theory would win. So wherever you’ve got one of these constants, you’ve got a sort of opportunity there. There’s a wonderful quote from Richard Feynman, basically saying, everyone, every physicist should put the fine structure constant, one over 137, roughly up on a wall and worry about it. And this was his point, is this. It’s an assumption. And if we could do better and not have to make an assumption and still explain all the data, that would be great.

The way this comes back around to the fine tuning argument is not that I’m ruling out deeper theory. It’s not that I think that God is going to be the deeper explanation of that. No, we keep doing science, right. I’m a scientist. I’m not saying we stop science now. And we all go to church. The point of the fine tuning argument is, if we’re trying to look around at other ways the universe could have been this fact about the deepest laws that we know now tells us that there is something remarkable about this universe all the way down to the bottom.

You’re amazement at seeing a a hummingbird. It goes all the way down, you should be amazed at the values of the fundamental constants of nature for the same sorts of reasons.

JB: I mean, coming back to you, Sabina, I mean, one of the earliest people to sort of make a comment on this phenomenon of fine tuning was Fred Hoyle you know, well known British physicist and he discovered, well he predicted a certain residence. And you’ll have to tell me the scientific aspect of this to get this right. But in carbon, which would allow, which would make sense of us being able to be here, of life being able to exist in the universe. Now, his famous phrase on that was that, “to all intents and purposes, it looks like something or someone has monkeyed with physics, and there are no blind forces, worth speaking of in nature.”

He obviously felt that there was something that needed an explanation here. And could you first of all, explain what Fred Hoyle was describing there, what he had discovered and why he thought it made it look as though, though he didn’t necessarily follow it to Luke’s conclusions, obviously. But why it made it look as though there was this this fine tuning going on, give us the specific example from the science first of all?

SH: Well, yeah, goodness, you’re putting me on the spot. So I can’t recall exactly how this argument goes. But it’s roughly speaking something of the type that is for nuclear fusion to continue in stars, the way that we observe it there needs to be a specific structure about the carbon nucleus, which was not known at the time, but Hoyle it said it has to be there otherwise, it doesn’t work. And it was later actually observed. So is this prediction turned out to be correct.

So Luke, please correct me if I get this entirely wrong, I think that’s, that’s as good as I can remember. And so I would say that’s an example of using the weak anthropic principle, you know, he just he made this observation like stars burn, we are here, there has to be something in this nuclear fusion cycle that allows for this. And that led him to this conclusion. That’s a fine scientific argument.

Now as for his feeling, that there’s something in need of being explaining, or that Luke says there’s something remarkable here that requires an explanation.

I don’t know what to do with these statements. You know, they’re not scientific statements. I don’t think they are warranted from a scientific perspective. Now, you know, if people feel that way, that’s certainly fine with me. But from a purely observational point of view, I don’t think we have any reason why there has to be this deeper explanation. And let me say, again, you know, it, I would be super excited if there was one, like, you know, if someone comes up tomorrow and says, Yeah, look, I can calculate all 26 parameters or something of the sun or model (38:02). Using a much simpler equation, you know, I would be super excited, because I would be convinced that there will certainly be more insights falling out of this. But for all we currently know, it just doesn’t have to be the case.

JB: I guess I’m interested in teasing out this particular example Luke, because I often think it helps to, to have a sort of specific example, in front of us. But this idea that that Hoyle predicted that the I think is something like the resonance of the carbon atom or something would have to take a very, very specific value in order to allow the fusion that would obviously enable us to exist as carbon based creatures and so on.

He felt there was something curious, that needed explaining at the heart of that, though, as I say, didn’t he didn’t end up becoming a theist or anything like that. What explain that example to us and and what your why you believe those kinds of examples do require an explanation beyond themselves, in a sense.

LB: Well, I can’t do much better explaining the physics and Sabina without doing a whole lot of maths. But the basic idea was, is there, you’re trying to smash two things together to make, three things in fact, together to make carbon.

And given the physics known to Hoyle at the time, it simply wasn’t going to work in large stars. Unless there was a bit of physics missing this, this way that carbon can wobble around, you know, oscillate and resonate in a certain way.

So why do I, why is this so. The reason I think why this affected Hoyle was just basically the thought, you know, as follows. There’s a wonderful quote from Dawkins as I think it must be behind me somewhere where he basically says, you know, “However many ways there are to be alive and it’s certain that there are vastly more ways to be dead, or rather not alive.” And he takes the example of if you take two grammes of matter, and you arrange it, most of those arrangements won’t fly, or reproduce or do anything like that.

So there’s this, this thought of, you know, what do you expect if there’s no deeper explanation of the world we see around us is that you wouldn’t expect there to be any sort of unlikely there’s that word again, sort of remarkable, interesting, you know, conspiracies that have to come together in order for us to exist, we just have to be, as Russell said, accidental collocations of atoms. So to find that our existence depends on what seems like a very unlikely thing to turn up in a carbon atom. That, again, that overturns some of the way that Hoyle thought about the world, I should say, and I have to put in this little this sort of asterisk that basically me and about four other people care about. Fred Adams has done some interesting work in looking at exactly how fine tuned this case is. There is a sort of back way around that you can, for the experts you can bind beryllium; is another way of getting anyway, it’s not quite as fine tuned as Hoyle thought it was, but there still are good examples. Let me put that asterisk.

JB: I mean, yeah, well, we could talk about other examples, obviously, that maybe have a firmer foundation. In that sense, I suppose where this leads me all, as a lay person here, Sabina is, I understand where you’re coming from. I think the idea that look, we don’t know if these values and the laws of physics could have taken different forms and so on. Therefore, it’s a pointless question to be asking. But I still get left with that nagging question of why a universe that produces us that can produce life, it still seems like even if the law is somehow, there was some mechanism that meant that all the physical parameters had to take the value they take, it still seems remarkable that they took those values and produced us. It just seems like, to me at least, it still feels like it needs an explanation.

It’s like what’s the principle that caused all of the laws to take the exact values that there were even even if they couldn’t have been different from they are, it still feels like, we still need to understand why they’ve taken that value. Does that make sense? So otherwise, you’re just sort of saying it’s a brute fact almost, that they are they take the value they take, as though that doesn’t need explaining? Does that does that make sense to you, Sabina?

SH: Well, as I’ve said a few times, what do you think needs explaining is not necessarily a scientific question, I would say from the scientific perspective, it does not currently need explaining, you know, the universe has to be some way. And it’s the way that we observed, that’s just a fact. And I think that the task of science is to come up with the best explanations for these observations as well as we can do. And I mean, explanation here, in, especially in physics, in a purely quantitative way, you know, we have these theories. And they, yes, they come with some parameters. But of course, the parameters are not the only assumptions.

There are lots of other assumptions that also go into these theories. Like, I don’t know, spacetime is a three plus one dimensional Romanian manifold, with the differentiable structure, and so on, and so forth, all that kind of stuff. And we use these theories to calculate observations, you know, the measurement results for our observations, and we do as best as we can.

And for me, that’s what science is all about. And as I’ve said a few times, you can certainly wish there is an underlying theory, and maybe there’s one, but maybe that just isn’t one, you know, maybe that’s just the best that we could do.

JB: Do, do you think the question, why is there even a universe? Why is there a, you know, a set of physical laws that take the value they do? Is that not a science question? Is that not a question that that you’re in a position to be asking? Is it a question that another person could ask a philosopher, a theologian?

I mean, I suppose I’m coming to the sort of the, you know, to that really metaphysical point of saying, science obviously, looks at the physical universe and we can make hypotheses and look at the data and, you know, make predictions and so on. But the question of, why is there a universe with physical laws, and does that itself need an explanation? You feel that that goes beyond the purview of science in your view?

SH: Yes, actually. So I wouldn’t even know how to formally phrase the question that you just posed. But even the question that Luke’s put forward like about the fine tuning? I would already say that this is not a scientific question. It’s just not a question that we know how to address with science. And you can certainly ask for an explanation, but it won’t be a scientific explanation. So my issue with this whole fine tuning argument, and by the way, this isn’t only something that comes up in cosmology and astrophysics. Particle physicists also use very similar arguments, though they phrase them a little bit differently. So it’s not exactly the same story, but a very, very similar ones.

That’s just a conflation between scientific reasoning. And, you know, you can call it philosophical reasoning, or maybe religious reasoning, depending on what side you’re, you’re on.

JB: So, Luke, do you think it’s a legitimate scientific question to ask, Where do the laws come from? Where does the universe come from? To kind of, I suppose go beyond the basic fact of physical reality to ask, does physical reality need an explanation?

LB: Well, let me shock the audience. And say no. It’s a philosophical, it’s a philosophical question. It’s not a scientific question. I totally agree with that.

If you think that the only good questions are scientific questions, then you’ll think that these aren’t good questions. I’d want to know why you think that. And the problem is if, if you think you gave a good answer to the question, why, you know, why are all good questions scientific questions; that’s going to be a philosophical answer, because it’s a philosophical question.

Anyway, the point I make, so I don’t want to replace science with God. Right? This is not the point. We’ll keep doing science, because of course, we will. I will, you know, I want to know how this whole place works. The point of this is, I think the way I want to phrase this, I don’t actually like the phrase ‘demands an explanation or needs an explanation’. I think, what matters is the possibility of a better explanation. That’s all. That’s all we have. And an explanation with fewer assumptions is a better explanation. The constants are assumptions. And so off we go.

In terms of the fine tuning argument, what we’re trying to think of is, you know, imagine this is it. And actually for most people, I think most physicists would not accept that, you know, maybe this is just the way the universe is; that would, that would be highly unlikely, but whatever.

Suppose this universe is the way it is, is, are there any deeper questions we still want to understand? And I think you’ve got two options here. You have a whole bunch of questions like; why is there a universe at all? Why is the universe the way it is, rather than some other way? Why does the universe obey scientific laws at all? Rather than just being a collection of events with no patterns at all? Why is there a universe in which life can exist when we have so so many examples of universe where universes where it couldn’t? What do we do with those questions? And they’re not scientific questions, because science can’t answer them. What do we do with them? We either say science is it; we throw them out, we try and, you know, you could call that naturalism. Sean Carroll calls that naturalism. I think that’s his book right there.

You either say, these are not the questions we could never get an answer to. We certainly can’t get a scientific answer and so we can’t get any answer, or, you know, whatever reason you have for that. Or the other option is, let’s look at the sort of things that might be able to explain it. And the theistic answer is the fine tuning argument tries to say that there is the possibility of a better explanation, whether it cries out for explanation, I think, is an unhelpful phrase, actually. But there’s the possibility of not just saying this is the way it is, but it’s the way it is, for a certain reason. And if that can actually do some explanatory work for us, perhaps not in terms of calculation. But in terms of rendering something that we know to be true to be more likely than it would otherwise be. Because probabilities change as a function of the hypothesis that you’re assuming. That’s an important point. Then we’ve got a reason there to think that those deeper questions have answers.

JB: Do you, Is that something that interests you, Sabina these deeper questions? I mean, there’s there is a sort of boundary point at which you can come to conclusion scientifically. Do you feel compelled in any way to go beyond that and to start asking those deeper philosophical questions about why there is a universe, whether the laws of nature are ultimately everything that exists or actually whether they too, need an explanation and so on?

SH: If you ask me personally, no, it’s just not what I want to do with my life doesn’t interest me very much. My shtick is more to try to tell physicists when they cross the border, from science to philosophy, or religion. And, you know, if Luke says that’s, that’s not a scientific question. It’s a philosophical question it still, it still wants an answer. These questions should be asked, people should try to answer them. Maybe by using different modes of explanation. That’s all fine with me. I just don’t want this to be conflated with scientific explanations, because I’m very concerned. And that’s what my whole book is about, that this leads scientists into a dead end, basically, where they’re trying to solve problems that don’t exist. And that’s pretty much what has happened in particle physics.

JB: I mean, you just just elaborate on that just a little bit, Sabina, because your book, as I mentioned, it’s called Lost in Math: How Beauty Leads Physics Astray, you think that there’s been too much of an emphasis on this idea of finding the beautiful solution? The you know, the something that looks wonderful. You think physics is just more messy than that, and are too many physics, physicists being led astray into a kind of metaphysical kind of sense of, there has to be some underlying structure, you know, that goes beyond just the physics of the universe?

SH: Well, the problem is that they are making metaphysical arguments, but don’t know it. They’re not, they’re not aware of what they’re doing. So they’re confusing the science, with the philosophy. So in particle physics, you will notice this, if you read the book, because I’ve interviewed quite a few people. They think these are just mathematical arguments. And they don’t realise that there’s actually quite a bit of metaphysics behind believing that this is something that even requires an explanation. And at least for particle physics, it has not worked, it just hasn’t worked. They’ve tried to use these arguments over and over again. And it’s a very similar story to the as I said, to the fine tuning cosmology, though, with a slightly different twist.

For exactly what you’re varying over and so on. I don’t really want to go into this. But but there too the argument is basically, well, you know, there’s some kind of constant it requires an explanation. And then we have come up with an explanation for that, you know, there’s this new particle or I don’t know, new field, or we need supersymmetry, and additional symmetry, unification, all that kind of stuff. And these hypothesis turned out to be wrong and wrong and wrong and wrong and wrong. It’s just been a dramatically unsuccessful strategy. And the point that I’m trying to get across well, that’s because you didn’t ask a scientific question in the first place. And so this is why, you know, I don’t want to stop people from asking these questions. That’s all fine with me. I want them to be aware that this is not a scientific strategy. It’s not a scientific methodology.

JB: I’ll come back to you for some comments on that in a moment’s time Luke. We’re heading into our final break. We’re talking about the fine tuning of the universe. Was the cosmos made for us? On the Big Conversation from Unbelievable? today. I’m Justin Brierley. My guests are Luke Barnes and Sabina Hossenfelder.

Part 3 – 54:07 on timecode

JB: Such an interesting conversation on the fine tuning of the cosmos today on The Big Conversation. Sabina Hossenfelder, is a theoretical physicist researching dark matter at the Frankfurt Institute for Advanced Studies, and author of Lost in Math: How Beauty Leads Physics Astray, I’ll make sure there are links to Sabina and her very popular YouTube channel as well, with today’s show. Also to Luke Barnes, who’s our Christian guests on the show. He’s an astrophysicist, researching things like galaxy formation, dark energy, and fine tuning of the universe for life. His book on this particular subject is A Fortunate Universe: Life in a Finely Tuned Cosmos, though, the more recent book is just behind you on your video camera, Luke.

LB: Strategically

JB: Just give us the title of that and a very brief explanation of what you’re doing in that new book.

LB: It’s called The Cosmic Revolutionaries Handbook or How to Beat the Big Bang. And I’m sure SabinA has got some great stories about this as well; ask any physicist, cosmologist, you get emails with people who say, “I’ve got the final theory of everything, here it is”. And all we want to do was just say, all right, if you want to do that, here’s how to do it properly. For starters, here’s the data that you haven’t bothered looking up to, you know, to actually explain, and here’s why we do things like peer review and publishing and, and those sorts of things. So it’s a tour of the universe, under the guise of: here are the most important facts that led us to the way we think the universe is. And if you want to do better, here’s how to do it.

JB: Fantastic. I’ll make sure there’s links as well to you as well, Luke, I mean, in that last segment, we sort of heard Sabina again, saying she thinks too many scientists are ending up asking unscientific questions, questions that are more metaphysical, that are more about finding some kind of purported beauty in the equations and in the underlying structure and so on. I mean, is the same true? Could the same be argued for the for the fine tuning sort of arguments that you’re making, you’re attempting to ask basically, an unscientific question about some scientific parameters essentially?

LB: Well, the reason I sort of said before that these are not scientific questions is because of what they’re about. I mean, these are not theories about how the universe work. And so, you know, by stipulation, then they’re not scientific theories. But I want to make a I think there’s something needs to be clarified here. There’s the fine tuning argument. And I said, that wasn’t scientific just because of what it’s trying to explain things in terms of. God is not a physical thing. The idea of God is not the idea of a physical thing. And so it can’t be a scientific theory. But I don’t actually think that fine tuning as it’s applied in physics is necessarily a philosophical belief. I think starting from the sort of Bayesian framework, there is a way there has to be a way of saying, alright I’ve got two theories, which one is the best?

And one way of thinking about that is which one makes the most assumptions to, you know, if you’re just counting assumptions, or the most implausible assumption, you know, has the most internal flexibility. And I think that the Bayesian approach has the best way of doing that. And that is, a scientific question, because we’re trying to appraise scientific theories. However, I don’t want to say, I’m an astrophysicist, I don’t want to say that everything that particle physicists have done in applying a fine tuning, or a related idea called naturalness, is fine. So actually, a lot of Sabina’s critiques of that I can be on board with. And in particular, this matters, because we’re building billion dollar machines to try and test these ideas is a very good reason to think very hard about what we think we’re doing. So. So I wouldn’t go as far as saying that they’re purely philosophical. But I don’t, I don’t want to just endorse them either. There are ways to do that sort of reasoning wrong.

JB: And when it comes to how you kind of move from the fine tuning to the belief in a in a creative God. Now, as you’ve said, yourself, you’re you’re not saying, God is the outcome of this. Is it more that you’re, are you doing a philosophical journey there, of saying, Well, given this phenomenon of fine tuning, which you do believe, obviously, against Sabina, is a valid sort of idea phenomenon. But given that, does it fit better with the view that there is potentially a creator behind the universe? Or that we’re living in a naturalistic universe that all that exists is the physical stuff of the universe? Is it simply that you’re saying if if you had to choose between the two options, you think it’s more consistent with with the idea of a god?

LB: Yeah, so I mean, I’ve I’ve tried to understand what the naturalist say when they say, you know, Sean, and Sabina, Sean Carroll and Sabina, have been saying these questions, feel free to ask them but there’s nothing we can do to know whether any answer to them is better than any other answer. I do think we can do better than that, which is what fine tuning is doing. These are metaphysical questions. These are philosophical questions, but I don’t think that means that we’re not allowed to ask them or that we shouldn’t ask them or that we can just go you know, this is the way the university is deal with it. I think it’s a it’s a basic principle principle, not just of science, but of rationality to try and put together the the your worldview in a way that explains the most with the least assumptions. And I think what fine tuning shows is that just assuming that our universe is going to be life permitting, if you want to put it that way, is a big assumption. Or to put it another way, there is something remarkable and rare about the way that our universe is in that it permits life.

JB: Yeah, I mean, again, I can kind of predict where you’re going go with this Sabina, I suppose but asking that kind of, that next level question. I mean, you’ve said at the beginning, you’re kind of I think, did you describe yourself as essentially atheist or agnostic? Does that sort of, does that impact the way you approach, if you like, the outcomes of your science? Do you think in a sense that you’re, you know, you’re going to assume that there’s no, nothing else going on beyond the physical science, because you’ve got, you haven’t been given any reason to believe in God? Is that fair to say?

SH: I really don’t think that it matters at all, for my research, just, you know, practically the way the things that I do, the calculations that I do, it plays, absolutely no role. I also don’t think that it has made much of an influence on you know, the more philosophical questions that I’ve been asking that I’ve been writing about, that I’ve been discussing.

But I have noticed a few times that when I talk to scientists, physicists, mostly, admittedly, who are openly religious, as opposed to those who would describe themselves as atheists, then the religious ones are the ones who are more careful about distinguishing between their belief based interests and their metaphysical assumptions and so on, than the ones who kind of think they’re, they’re above it, right, because they’re not religious. So that’s just, you know, an observation that I have made. But I guess to what Luke just said, I would say probably the predictable thing, if you say, there’s something remarkable about it, there’s something rare about it, I would say that these are just things that you can’t quantify. It’s not a scientific statement, I have no doubt that you feel about it this way. And probably a lot of people do it. But I wouldn’t know how to phrase it scientifically. And that’s something that I just can’t work with.

I also especially this issue about the rarity, I would have no idea how to even quantify something like this. Like if you say, Well, you know, the universe could have been anyway, but let’s just assume that it can be described by mathematics just so we have someplace to start with. Then you have what Max Tegmark called “the mathematical universe”, you know, there are all these possible mathematical structures. And the ones that we observe to describe our universe is an infinitesimally small part of that. So and and how much do you know about how likely something like life, which we can’t even agree on what it is, is anywhere in this mathematical universe? We have absolutely no idea. I’m not even sure that that’s a question which, to which the answer can even be quantified. So it’s just something that I, I can’t make any sense of.

JB: I mean, one of the phrases Luke used earlier, which I thought was quite interesting was, the question is whether you think there are good questions outside of science in a way. And now you’ve said that, obviously, for your research, you don’t need to be asking anything other than purely scientific questions. And that’s totally understandable. But are you interested yourself in questions beyond science? I mean, do you, is it a valid question to be asking in the first place? You know, is there something beyond the universe that explains the universe? Or do you think that the only kinds of questions we should be asking, are those purely scientific questions?

SH: Well, I certainly I do have non-scientific questions, like, for example, how do I fill in my stupid tax forms? Right.

But I mean, and certainly the more philosophical questions that I’m interested in, though, I have to admit, that’s mostly to the extent that I think maybe one day they might become scientific questions. So I’m afraid I’m very much the scientist. So yeah, maybe since I know we’re nearing the end. Maybe that’s a point worth emphasising. There have certainly been scientific, philosophical questions in the past that at some point turned into scientific questions, like the cosmological principle for example, since we’re already talking about cosmology. That’s something that scientists have found a way to approach actually ask the question, you know, how uniformly distributed are is metal stars, galaxies, actually in the universe is something (1.04:46) that was once considered to be a philosophical principle. And now we have you know, a lot of this research about consciousness, that’s something which was not too long time ago in the field of philosophy, but now it’s more and more turning into a scientific discipline. And maybe there are other areas where this will also happen.

JB: What about you, Luke? Do you do approve of the overlap? You know, do you think you have to go get philosophical at some point when you, I suppose, reached the boundaries of what science can tell you?

LB: I think, for me, the difference between science and philosophy is what it’s trying to understand rather than any, I think there is, you know, epistemology and the theory of how we know things, that we know anything. I think once you’ve got a firm epistemology, you can then aim that to try and understand the world. And in terms of the world, and that’s science. Or if there’s a hypothesis, which is not about the physical world around us, we could aim ours say, at the same epistemology, you know, asking good questions and logic and pulling together the information we have and Bayesian probabilities and, and all that sort of stuff. And we can aim them at those questions as well. And so for me, it’s not that, so I would I disagree that science becomes philosophy, but never mind that that might just be worrying about words. But if for me, there’s sort of a coherent, an integrated whole there. It’s not that, you know, saying a question is unscientific is just to say what it’s aimed at trying to understand rather than any sort of, you know, rejection of that idea, it’s not a put down. There are questions that try to be scientific, but fail. So unfalsifiable scientific theories, but that’s another issue.

JB: Sure, sure. It’s been really interesting having you both on to discuss these questions. I suppose I’d be interested, just as we begin to wrap things up, Sabina, you’ve said, you know, from the outset, that the kind of the god question just doesn’t particularly interest you, you’re interested in the science and you don’t think you’ll ever, the science could ever provide any kind of evidence for for the god question. That’s a kind of separate sphere, I suppose, you know, the non-overlapping magisteria, as some philosophers and scientists have put it, but obviously, you know, as I said, at the beginning, you are a multifaceted person, you enjoy the singing, you enjoy, you know, the relationships and everything else. And, when I looked at some of your videos, you know, they are, in a sense, asking big questions about life and love and meaning and purpose and that kind of thing.

So, in that sense, it strikes me, you go beyond the science, in some areas of your life, you do sort of, in a sense, those kinds of questions, presumably you don’t think have scientific answers. When you put a video together, a music video, you’re not particularly, necessarily just thinking about: How will you know, what is the scientific aspect of this, you’re looking to engage someone emotionally, and everything else in that. So in that sense, I’m just interested to know do you think there’s a different part of your personality that would be open to the God question, or do you think that’s a sort of You don’t just you just don’t have to go there in that sense?

SH: Oh, well, I’m certainly open to the God question. I just don’t really see that there’s any interesting information coming in anytime soon. I guess. I would, I’ve been a little confused by what you just said about, you know, would science ever provide evidence for God or something like this. So I guess if that happened, then I would not longer considered to be religious God (1.08:51). So I, so I guess I kind of really think of these things as two non overlapping areas.

Yeah, does that suffice as an explanation?

JB: I understand what you’re saying, I suppose what you’re saying is if someone did present some scientific evidence for God, then it wouldn’t be the God as you understand God to be defined because it would become part of the natural world, it would become something you could, you know, physically, sort of investigate that.

SH: Exactly

JB: That’s a very fair point. I suppose what I would be interested, though, is if could you imagine what sort of type of evidence it would be then if it’s not scientific, if it was something else that would draw you towards that belief? I mean, I’m asking you a hypothetical here, obviously, but could you imagine what sort of thing you would need to entertain the idea at least that there that there’s a God behind everything?

SH: Not really, no, I can’t think of anything.

JB: You don’t know what that would be? Well, that’s fair enough because you know, I suppose most of the time, we don’t know what something is until it’s presented to us as in that way.

Luke, do you think people kind of have to start out with a religious inclination to see fine-tuning as potentially evidence for God? Or, I mean, you’ve co-authored this book with your atheist colleague, Geraint Lewis.

I’m just wondering, you know, when we come to these questions, whether the worldview we bring with us inevitably informs the way we’re going to interpret the evidence, and, you know, you did come to this question as a Christian. And so is it natural then to say, Well, of course, you’re going to say, you know, there’s a potential divine explanation for this, whereas an atheist like Geraint, and indeed Sabina is going to say, No, I don’t think we need to go in that direction.

LB: Well, I love that the story told by Alister McGrath, who said he’d given a presentation, which involved just discussing the basics of fine tuning, as I presented them before, and someone in the audience talked to him afterwards and said, it’s one of my favourite quotes about fine tuning actually, “I’m not religious, but something weird is going on here.”

I think, you know, Hoyle’s point that, you know, he was an atheist, and yet this sort of took him aback a bit, does say that there is something there now, maybe after all is said and done, you know that that initial reaction you then analyse and when Sabina does that she doesn’t see the numbers she needs, so no further.

I think you can get though; I’ve got a paper in a philosophical journal called A Reasonable Little Question if you want to say my attempts to towards the numbers on it, maybe it’s not convincing. But I do think, you know, you try not to just, confirmation bias is one, it’s really hard to avoid, it’s really hard not to just read all the books that you agree with already, and just have a wonderful time agreeing with all these people who already agree with you.

And so I think fine tuning, you know, it does fit into my worldview. nicely. I think it doesn’t fit into naturalism as nicely. But that’s a point of contention. But I think I mean, just, the important thing for me that I keep trying to do is to read not only people who are atheist, or who don’t believe in God, or agnostics, who criticise fine tuning, but the ones who then point out the stuff about our universe, which doesn’t look so nice and wonderful and lovely, like evil and suffering and all that sort of stuff. So I think, I mean, fine tuning whatever it is, it’s only one piece of the puzzle, it might be a very small piece, as we try to think through these big issues. So for me, it’s been, you know, I had a policy last year that for every two audio books, every three audio books, one of them I had to disagree with, from the start, that I read through, and I’ve been trying to do, it was a very challenging year! but I think that’s what you’ve got to try and do.

JB: Well, either way, it’s been great having you both on the show. And Sabina, I guess ultimately, even though you obviously don’t see any evidence for God, from the science and so on, you’re still as you said at the outset, you find the fact that we can be sitting here discussing these ideas, you know, doing particle physics pretty amazing in and of itself that that at least perhaps we can all agree on. Right?

Great. Well, look, it’s been wonderful having you both on the show. Thank you very much for taking the time and I will make sure there are links with today’s programme, where people can find out more about you. But for now, Luke and Sabina, thanks for being with me today.

SH & LB: Thank you.