Episode 302: A Philosopher and a Physicist Discuss Probability and the Fine Tuning of the Universe with Dr. Timothy McGrew and Dr. Luke Barnes

Summary

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Apologetics Profile Podcast

Episode 302: A Philosopher and a Physicist Discuss Probability and the Fine Tuning of the Universe
Guests: Dr. Luke Barnes (Astrophysicist) & Dr. Timothy McGrew (Philosopher)
Hosts: James Walker and Daniel Ray
Release Date: August 18, 2025

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Episode Overview

This episode explores the intriguing intersection of fine-tuning in cosmology, probability theory, and philosophical inquiry. Astrophysicist Dr. Luke Barnes and philosopher Dr. Timothy McGrew join the hosts to dissect arguments about the apparent fine-tuning of universal constants, the use and limits of probability (especially Bayesian reasoning) in this context, and what such observations might imply about the existence of God.

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Key Discussion Points & Insights

1. Science, Metaphysics, and the Fine-Tuning Argument

(00:19–07:06)

• The hosts introduce the problem: the universe’s physical constants appear peculiarly "fine-tuned" for life. This observation has sparked debates about whether such tuning points toward design, chance, or a deeper physical explanation.
• Science as Philosophy: Science is often portrayed as a purely empirical, evidence-based pursuit. However, both theists and atheists rely on metaphysical assumptions, especially regarding questions about God’s existence.
• Anthropic Principle: The idea articulated by Carter, Barrow, and Tipler that our universe appears "privileged" for life, leading to the anthropic principle—observers can only exist in universes capable of supporting life.

2. Physics vs. Mathematics and the Question of Probability

(07:06–10:17)

• Luke Barnes: Highlights the crucial distinction between mathematics (abstract reasoning) and physics (meaningful application to reality).
  • “Physics is not mathematics, and mathematics is not physics. One helps the other. But you have to have some understanding of the connection of the words with the real world.” (07:06)
• Probability in Fine-Tuning: When asking, “What are the chances of this universe?” we move into probability arguments—often employing Bayesian reasoning.

3. Bayesian Probability in Physics and Cosmology

(09:18–10:34)

• Luke Barnes: Points out that Bayesian methods are mainstream in contemporary physics and astronomy.
  • “Last time I checked, there were around about 20,000 papers in physics and astronomy journals that have the word Bayesian in the title...” (09:18)
• Timothy McGrew: Affirms the indispensability of Bayesian tools in science, especially astrophysics.
  • “Astrophysics today is just, I think, not even conceivable without the use of Bayesian tools.” (10:17)

4. How to Frame the Fine-Tuning Argument Using Probability

(12:38–19:23)

• Barnes’s Approach: Recognizes the challenge of considering “all possible universes” and proposes a more tractable method for assessing fine tuning:
  • Keep the laws of nature constant and vary only the parameters (the “constants”).
  • Use a sample approach (like polling for elections) since we can't assess every possible universe.
  • Employ a uniform probability distribution over this finite parameter space to reflect ignorance (i.e., “I don’t know”).
  • Finds that even with these limitations, our universe’s values are highly unusual and life-permitting.
  • “If anything, the bias is going in the naturalist's favor. …And ours does amazingly rare and wonderful things like puts two particles together and makes the periodic table...” (12:38)

5. Infinities and Philosophical Challenges

(19:23–27:17)

• McGrew’s Critique:
  • Discusses his pivotal paper on the problem of infinities in fine-tuning arguments.
  • Philosophers want to address the grand question: Out of all logically possible universes, how likely is a life-permitting one?
  • It’s mathematically impossible to assign a uniform probability distribution over infinite possibilities: “You cannot smoothly spread probability across an infinite target.” (19:42)
  • Analogy: Like trying to spread finite butter over infinite bread—it can't be done.
  • Philosophical challenge: If probability is spread over all possibilities, fine-tuned and non-fine-tuned outcomes are rendered equivalently unremarkable.

6. Seeking Tractable, Meaningful Models

(27:17–34:05)

• Both guests agree that trying to analyze all logically possible universes is a nonstarter.
• Instead, they justify using simplified, physically-motivated models that vary only the constants we know and keep the rest fixed.
• McGrew: “The trick is to come up with something that we think actually sheds at least some light. I think Luke is saying, yeah, it’s not going to… solve the global problem. …But then suppose that we say, well, let’s hold quantum field theory and general relativity constant…that range, as I understand…is finite…and we can talk completely intelligibly about putting a flat distribution down on it.” (34:05)

7. Intuition, Caution, and the Problem of Evil

(32:58–39:33)

• Barnes: The fine-tuning intuition is powerful (“I’m not religious, but something weird is going on here.”), but caution is needed not to overstate the argument.
  • “…the idea of, okay, let's take this sort of physics approach where we just try and find the closest reflective problem that we can solve…” (27:32)
• A parallel is drawn to the Problem of Evil: Just as it's hard to say what we should expect from a deity, it’s difficult to say what we should expect from “nature” or “naturalism” at the universal scale. Both lines of inquiry run into problems of infinite or unbounded possibilities.

8. The Multiverse and Skeptical Moves

(41:18–43:06)

• Barnes critiques multiverse reasoning as a “get-out-of-fine-tuning-free card”—it suggests deeper physics we don’t know, but moves the goalposts into an even more unknowable realm.
  • “For me, it’s the equivalent of taking your bat and ball and going home. …If you’re going to be skeptical, just say you’re going to be skeptical. Don’t throw it behind this sort of… facade of, oh, I’m doing more cosmology.” (41:18)

9. Bayesian vs. Frequentist Approaches in Science

(43:33–53:53)

• Dr. Sabina Hossenfelder’s Critique (quoted): Probabilities in fine-tuning arguments are unscientific because they're based on what we already know and don't require deeper explanation.
  • Barnes responds that this “finite frequentism” is limited—Bayesian methods (“inverse reasoning”) are far more widely used and integral to physics and cosmology.
  • “You just can't throw this sort of approach away. Like it's just too useful. Too many scientists doing, too many different types of scientists think that this approach is… a good way to approach probabilities.” (47:12)
• McGrew: Explains the logical necessity of Bayesian reasoning and why it is so widely adopted. Asks for initial probabilities to be tied to empirical data wherever possible and pokes fun at both camps:
  • “Frequentists use rigorous mathematics to answer questions nobody was really interested in. Whereas the Bayesians give us definite numerical answers to the questions we really wanted answered by means of assumptions nobody quite believes.” (47:41)
  • Advocates for combining observed data with Bayesian inference, conceding that both have roles.

10. The Deeper Puzzle: Why Is the Universe Intelligible?

(56:24–58:28)

• The hosts quote Wigner and Vilenkin on the “miracle” of mathematics’ uncanny applicability to the natural world—why should the universe be intelligible to us at all?
  • McGrew: “The intelligibility is a matter of the fact that we can write down a few equations and get a grip on so much. Now that’s fascinating. …That keeps me up at night.” (57:56)
  • Barnes: “I don’t think there’s any reason the naturalist can give to expect there to be laws of nature at all. ...That's a drive by at the end.” (58:28)

11. Tangential Segment: The Bible Manuscripts Chart

(60:05–62:48)

• In an unexpected but charming detour, Barnes discusses his animated chart plotting New Testament manuscript evidence—reflecting his broad analytical curiosity.
  • Visualizes the growth in Bible verse manuscript evidence over time.
  • McGrew: Adds historical context on manuscript survival (papyrus/conditions), and notes the relevance for historical reliability.

12. Fine-Tuning & Christianity: The Final Connection

(62:48–64:25)

• How does fine-tuning connect to the God of the Bible?
  • McGrew: “We have more data than we were working from for just the fine tuning, right? ...You widen your field of data, then you are in a position to do more.” (63:09)
  • Barnes: Fine-tuning alone doesn’t get one to Christianity, but it’s a step. He encourages skeptical listeners to read the New Testament.
    • “Fine tuning could be an argument for Islam...we're going to need more evidence than that. But it's out there, so go look at it. Go read the New Testament.” (63:46)
  • They discuss H.G. Wells on Jesus as an unavoidable figure in human history regardless of theological bias.

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Notable Quotes & Memorable Moments

• Dr. Timothy McGrew:

  • On infinite probability spaces:
    “It’s like taking a finite amount of butter, even continuously divisible butter, and spreading it over an infinite piece of bread. You can’t do it smoothly…” (19:42)
  • On tractable vs. trivial models:
    “There are clearly problems that are tractable but trivial. …The trick is to come up with something that we think actually sheds at least some light.” (34:05)
  • On the unity of probability and empirical data:
    “We need to… look at the stuff that we can count and we need to be measuring things and pulling some of our probabilities…from observations…This is an enormously powerful tool. Everybody should use it.” (47:41)
  • On the intelligibility of the universe:
    “We can write down a few equations and get a grip on so much. …That keeps me up at night.” (57:56)

• Dr. Luke Barnes:

  • On physicists’ methods:
    “There’s a famous joke about a physicist solving the problem for a spherical cow in a vacuum…” (12:38)
  • On naturalistic expectations:
    “I don’t think there’s any reason the naturalist can give to expect there to be laws of nature at all...” (58:28)
  • On fine-tuning’s curiousness:
    “I’m not religious, but something weird is going on here.” (27:32)
  • On the multiverse as a skeptical retreat:
    “For me, it’s the equivalent of taking your bat and ball and going home.” (41:18)
  • On Bible manuscripts:
    “I could have some fun with this...I'm now wondering whether this is interesting to anyone. I had some fun.” (60:42)

• On Bayesian vs. Frequentist Probability:

  • Barnes: “You just can’t throw this sort of approach away. Like it’s just too useful. Too many scientists doing, too many different types of scientists think that this approach is a good way to approach probabilities here.” (47:12)
  • McGrew (the joke):
    “Frequentists use rigorous mathematics to answer questions nobody was really interested in. Whereas the Bayesians give us definite numerical answers to the questions we really wanted answered by means of assumptions nobody quite believes.” (47:41)

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Important Segment Timestamps

• 00:19 – Science & metaphysics in fine-tuning
• 07:06 – Barnes: Physics vs. mathematics
• 09:18 – Bayesianism's prevalence in physics (Barnes)
• 10:17 – Bayesian tools indispensable (McGrew)
• 12:38 – Barnes: Framing the argument with probability
• 19:42 – McGrew: Philosophical problems with infinities
• 27:32 – Barnes: Physics-style simplification & intuition
• 34:05 – Joint agreement on tractable problem modeling
• 41:18 – Barnes: The multiverse critique
• 47:41 – McGrew: Bayesian vs. frequentist joke and insight
• 53:53 – Barnes: On using probability under uncertainty
• 57:56 – McGrew: Marveling at the universe's intelligibility
• 58:28 – Barnes: Why expect laws of nature under naturalism?
• 60:42 – Barnes: Describing the Bible manuscript chart
• 63:09 – McGrew: Connecting fine-tuning argument to biblical faith
• 63:46 – Barnes: Fine-tuning, Christianity, and evidence

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Conclusion

This conversational deep dive between a philosopher and a physicist offers listeners a rare and balanced glimpse into the strengths, limits, and philosophical depths of the fine-tuning argument. While both guests express admiration for the intuitive pull of cosmic fine-tuning, they emphasize the need for intellectual caution and methodological clarity. The episode closes with a reminder that fine-tuning raises major questions—but is but one piece in a larger mosaic when it comes to the questions of God, purpose, and the credibility of the Christian message.

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Transcript

[Dr. Luke Barnes]

You are listening to Watchman Fellowship's Apologetics profile podcast.

[Dr. Timothy McGrew]

There's nothing in the New Testament of the Bible about electrons or protons. There's nothing there that I have seen in the Bible that informs modern science.

[Dr. Luke Barnes]

So the people who wrote the Bible.

[Dr. Timothy McGrew]

Were they were literate, but they were.

[Dr. Luke Barnes]

Not literate in the modern scientific sense.

[Dr. Timothy McGrew]

So you have to reckon that man.

[Podcast Host / Narrator]

Science popularizers often give the general public the impression that science as a formal discipline is a tool for investigating the physical universe is a strictly evidence based endeavor. In other words, here's the physical evidence of our theories. Problem solved, case closed. Seen this way, the interpretations and pronouncements of scientists regarding the physical world appear sacrosanct. End of story. Who are we to argue with them now? To be completely fair, that is not how all practicing scientists actually view their profession. But this popular view is nevertheless promulgated by many non scientists, theists and on theists alike, in defense of their particular stance on the existence of God. Skeptics, for example, might appeal to science in an attempt to argue that God does not exist. Theists might invoke science in an attempt to argue that God does indeed exist. But of course, the question of God's existence isn't finally a scientific one. Both atheists and theists, even scientists themselves, no matter their personal beliefs, use some philosophy in their conclusions about the nature of the universe, especially when it comes to the question about the existence of God. In other words, science is not strictly an empirical endeavor. As professor of philosophy Jason Waller notes in his 2020 book Cosmological Fine Tuning Arguments, what, if anything, should we infer from the fine tuning of our universe for life? At some point, the questions stop being empirical ones and become metaphysical, whether we like it or not. When we reach that point, we can do the metaphysics well, or we can do it badly. But there is no other way forward. There are many false metaphysical views, but some may still be closer to the truth than others. End quote. The idea that the universe in which we find ourselves seems extraordinarily fine tuned for our creaturely existence within it was an idea that began to gain traction in the physics and cosmology communities in 1974 with a formal paper published by Brandon Carter titled Large Number Coincidences and the Anthropic Principle in Cosmology. In the opening of the paper, Carter noted that what we can expect to observe must be restricted by the conditions necessary for our presence as observers. Although our situation is not necessarily central, it is inevitably privileged to some extent. To put it another way, we would not be here observing the universe if the initial and necessary conditions for our existence were not free first in place. We might not be at the cosmographical center of the cosmos, but we are, Carter recognized, privileged to some extent. Our existence is a curious matter, scientifically and cosmologically speaking, given what science knows about the laws of the universe. Carter coined this curiosity the anthropic principle. In 1986, Frank Tipler and John Barrow published their landmark book, the Anthropic Cosmological Principle, an extraordinarily detailed follow up to Carter's insights. Tipler and Barrow Observe on page 31, current physical theories are extremely successful. This success itself is still a mystery. After all, there is no obvious reason why we should find ourselves able to understand the fundamental structure of nature. It is also infinite, part a consequence of the fact that we have found nature to be constructed upon certain immutable foundation stones, which we call fundamental constants of nature. As yet, we have no explanation for the precise numerical values taken by these unchanging dimensionless numbers. They are not subject to evolution or selection by any known natural or unnatural mechanism. The fortuitous nature of many of their numerical values is a mystery that cries out for a solution. And that solution, as Waller noted previously, involves metaphysics, ideas, theories, explanations and beliefs that go beyond physics, beyond strict empirical science. Thus the meta prefix meaning above or beyond. Just a sampling of some of Barrow and Tipler's immutable foundational stones. The constants of nature that comprise the fine tuning argument include the speed of light, the Planck constant, the gravitational constant, the fine structure constant, the strong and weak nuclear forces, and the electromagnetic force, just to name a few. Collectively, and quite mysteriously, to many scientists, all the constants seem to be essential for for our own existence. Changing the value of just one of the constants would impact all of the others to varying degrees. But any change to any of the constants quickly threatens the existence of carbon based life as we know it. And as Barrow and Tipler pointed out, these numbers quite literally just come to us out of the blue. There is presently no known equation physicists can calculate that would give them the values of these entities as they are known today.

[Dr. Luke Barnes]

Mathematicians, prepare abstract reasoning that's ready to be used if you will only have a set of axioms about the real world. But the physicist has meaning to all the phrases. And there's a very important thing that a lot of people who study physics that come from mathematics don't appreciate. That physics is not mathematics, and mathematics is not physics. One helps the other. But you have to have some understanding of the connection of the words with the real world.

[Podcast Host / Narrator]

And so we are left to ask, what are the chances that this universe came into being naturally with these peculiar constants, whether we are aware of it or not? By asking the question, what are the chances? We've just invoked a probability argument and have likely raised the eyebrows of any professional philosophers that might be within earshot, not to mention any physicists or cosmologists who might be standing nearby as well. But most of us, myself included, are not well versed in formal probability theory or the physics of the universe, for that matter.

[Dr. Luke Barnes]

Matter.

[Podcast Host / Narrator]

How can we contribute anything to such formalized and complicated theorizing? It's all over our heads. So what do we do? The fine tuning argument does seem to appeal to our common sense. Everything sure looks like it was designed, at least in part, for our existence. Isn't it obvious? At face value, it seems utterly improbable that this universe just popped into being on its own with these peculiar constants and quantities that are apparently life permitting. Do we need to overcomplicate it all by invoking Bayesian probability theory? While Bayesian probability theory can be, and often is intellectually intimidating for many people, myself included, it is at bottom, relatively easy to understand its larger aims. And it is important to know that Bayesian probability is widely utilized in physics and cosmology as a tool for understanding the cosmos. This is astrophysicist and cosmologist Dr. Luke Barnes.

[Dr. Luke Barnes]

Last time I checked, there were around about 20,000 papers in physics and astronomy journals that have the word Bayesian in the title of the paper. Not just used, not just this approach used in the paper. So important and integral to the paper itself that it's in the title. But they, they felt the need to tell the, you know, that this is a Bayesian approach to this or that or whatever. I think you just can't throw this sort of approach away. This is not, you know, made up on the spot approach by theists trying to make an argument out of nothing. Like, it's just too useful. Too many scientists doing. Too many different types of scientists think that this approach is, is, is a, is a good way to approach probability.

[Podcast Host / Narrator]

And Luke's observations here about Bayesian reasoning are backed up by professor of Philosophy Dr. Timothy McGrew.

[Dr. Timothy McGrew]

Luke is absolutely right. It's used all over the place in science, but most particularly in astrophysics. Astrophysics today is just, I think, not even conceivable without the use of Bayesian tools.

[Podcast Host / Narrator]

And so our conversation on the broadcast today with a physicist and a philosopher, how might we reconcile our intuitive marveling and wondering about the universe and our place within it with a finely tuned probabilistic argument? Can probability theory cohere with our intuitive senses that the universe is indeed exquisitely fine tuned for our existence? As theologian Alister McGrath. Human beings long to make sense of things, to identify patterns in the rich fabric of, of nature, to offer explanations for what happens around them, and to reflect on the meaning of their lives. So the quest for understanding our place in the cosmos isn't just a quirk of late modernity or contemporary science. It is a long standing ancient tradition. As if the universe were intentionally designed to provoke our wonder and awe. As King David marveled 3,000 years when I consider thy heavens, the moon and the stars, the work of thy fingers which thou hast ordained, what is man that thou dost take thought of him, and the Son of Man that thou dost care for him. Our guests on the broadcast this week, astrophysicist Dr. Luke Barnes and philosopher Dr. Timothy McGrew will help us fine tune our thinking about fine tuning. Luke and Tim will be discussing the intersection of physics and the philosophy of probability when it comes to the fine tuning of the universe. And as we begin the broadcast, we'll first hear from Luke as he explains his current thinking on the intersection of fine tuning arguments and probability theory. Here is Dr. Luke Barnes.

[Dr. Luke Barnes]

The fine tuning argument. Here's the way I've been thinking about it recently in light of chatting to especially philosophers. So it sounds like what, what the fine tuning argument is trying to say is it starts with the statement like of all the possible universes and you know, life permitting ones are a very small fraction. And then, you know, some philosophers have quite rightly pointed out, well, what on earth, how on earth do you think you've got a handle on all possible universes, right? What, what? You know, I could, I could imagine there being such a set maybe, but you starting to say things like oh, you know, I can say this fraction or that fraction or whatever. Well no, not quite. Let's, let's, let's try and build it up. So there's various arguments. So, so let's take a different argument just for comparison. Suppose the atheist says something like the problem of evil. You know, if, if there was a God, I wouldn't expect a universe with this much pain and suffering in it and that has at least some sort of prima facie power to it. But if you really want to consider these arguments from a bayesian point of view from, by weighing up probabilities. If you think it's a lockdown logical certainty this wouldn't be the universe God creates, then fine, that's great. We don't have to do any of the Bayesian stuff. But if you're not sure, the other question you've got to ask is what sort of universe would you expect on naturalism? And I think that's really the question that fine tuning allows us to go after. If you really think that's an important question for various, for design arguments, for even for problem of evil sorts of arguments. The sort of question of all right, there's a naturalistic universe behind that door over there. What do you think is going to be there when you open the door? And what fine tuning says is, well, look, we could start off by just everyone just imagines their own private naturalistic universe. We all just imagine what's behind the door. And like we could do that, but it doesn't seem particularly profitable. Can we do any better? And fine tuning says, hey, I've got a method for you. Look, I can't begin to pretend that I've got a handle on all possible, say, laws of nature. I mean, there are some we just haven't even thought of yet. There are some written in mathematical rules where we haven't even discovered the mathematics yet. So that's not going to happen. Could I just sort of, in the spirit of doing a, you know, a survey without asking everybody of instead of talking about a population, talk about a sample from the population. Is there a way of making some sort of set of universes that I can sort of explore in the same way that a survey of who's going to win the next election doesn't ask everybody, that would just be the election. It just asks, you know, a sample from somewhere. Can I make a sample? Here's the proposal. Let's keep the laws of nature the same as in our universe, because that's what we've got. We've chosen those laws not because they're life permitting or not life meaning or whatever, just because they're here and we know them. Let's hold those laws constant and let's then constant. Let's change the parameters that go into that, those laws, because there's a set of 31 of them. They're just numbers. We varied them anyway just for doing science. And you know, that'll give us a test case. And if anything, the fact that we chose our laws biases us in favor of finding universes like ours. So if anything, the bias is going in the naturalist favor. All right, so we're going to vary these constants. What happens if I come up against an infinite range now? Well, the whole point was to find ourselves a manageable problem we can actually solve, which reflects the real problem that we want to solve, but was too hard. So if we come up against some infinities we can't handle, well, we start again like we just. We just find ourselves a problem we think matches the one we want to solve. This is classic physics style argumentation. There's a famous joke about a physicist solving the problem for a spherical cow in a vacuum. You can go look up that joke for yourself. So in, in particular, there are some numbers where, if you take the best physics we have today, that includes general relativity and it includes quantum field theory. And all you need to know about those two things is we don't know how to put those two things together. Which would happen, as I say at the top here, when you've got a really. When both quantum things and gravity things are relevant. So something very heavy and very small, like the early universe being really dense and really hot or whatever, right? High energies, all that. So. So we don't know what to do up there. And in particular the reason we don't know what to do is if you ask what, what happens up there and you ask general relativity and you ask quantum field theory, they give you different answers to the same question. What if I just fired two electrons at each other? Well, quantum field theory might say they bounce. It's a bit more complicated. But whereas general relativity might make a black hole. And so two answers to one question. And that tells us that we're missing a bit of the puzzle. We don't know how to put those together. So let's say, all right, where we don't know what's going on. Let's just. For our model, because we're just modeling our own ignorance, modeling the what's behind the door question. Let's just cut things off there. If there are other parameters we just can't handle, we'll just, we just can't handle that. We don't, we don't do that. Let's just. Within the limits we have, using uniform probability measures over finite limits, where we can to say, look, this is just the statement, I don't know. That's how I mathematically say dunno, right? Uniform probability distribution. Then we say, all right, well what's amongst that set of universes? What's ours like? And ours does amazingly rare and Wonderful things like puts two particles together and makes the periodic table and all those sorts of things. So that's my. I think we need to acknowledge the sort of limitations of what we're trying to do from the start. It's the sort of limitations a physicist does very naturally, which is why I think it has. This hasn't been stressed as much, but that's. We'd love. We're trying to answer the question of all possible universes, what sort would a naturalistic universe be like? What sort would a theistic universe be like? That question is too big. But I've got this really remarkably good test case, I want to say, of. Let's just vary the constants when we can. And that gives us some very interesting answers.

[Podcast Host / Narrator]

In 2001, Tim and his wife Lydia published a paper on the problem of infinities in probabilistic arguments pertaining to fine tuning, titled Probabilities and the Fine Tuning A Skeptical View. I asked him how he saw his paper's thesis in light of Luke's observations.

[Dr. Timothy McGrew]

As a philosopher, I came to the fine tuning argument first by reading about it in John Leslie's. John Leslie is not a cosmologist. He's not an astrophysicist. He has read the Carter material and the Barrow and Tipler material. But in his book Universes, he formulates a version of a fine tuning argument. And he does so in explicitly probabilistic terms. It's an absolute heck of a good read. Like whatever else you think, you should sit down and you should read Leslie's book because it's just so much fun. But I was scheduled to give a talk at a conference and actually gave this talk that was the basis of the paper that we ended up publishing. And John Leslie was in the audience. So we had a good convo, and he was actually very, very engaging. He liked the fact that we were taking it seriously, that we had something to say that he hadn't heard before. And so that was fun. The problem that we came up with, I could describe this way. So philosophers less accustomed to saying, or maybe we should. We wish we were less accustomed to saying, oh, let's. That problem's too hard. Let's solve some other problem. No, we want to just go straight for the big one, right? And so a universe of such and such a type given atheism is very, very small but finite. How'd you get the number? And the problem that we ran into was that if you really just take a. Here's a wild west of possible universes, anything and Everything that is logically consistently describable is somewhere in the pile. Then since there are parameters that don't have intrinsically a logically bounded value, there's just no reason that they can't go beyond 42. Then you end up with great infinite stretches rays, or maybe even entire entire number lines of possibilities for these things. And the difficulty then comes when you try to say, take a two dimensional target as an example. But imagine to the extent that our brains can do this, that it is unbounded, it is infinite. And you want to say, but this, you've got the same probability of hitting any square centimeter of it as you have of hitting any other square centimeter. Well, what probability is that? Turns out that because there are strictly countably infinitely many square centimeters on there, you can't say of any bit that it has any finite probability of being hit. Because the, the tiniest finite probability you try to put in there multiplied across the infinitely many square centimeters gives you infinity. But infinity is not a probability. Probabilities go up to 100% and they stop there. So the trouble is you cannot smoothly spread probability across an infinite target. You could, you could do it with sort of a two dimensional analog of a bell curve. No trouble at all. Right? We can normalize it under there, you've got most of the probability mass over here and then it sort of spreads out rapidly asymptotically towards zero and it all normalizes to a hundred percent. Perfect. Easy. We have models to do that. We actually have many, many models to do that. But what that does not do is treat every single possible allocation of values from behind a veil of occurrence where we just say, now we're just starting with no assumptions about this whatsoever. We're not going to give preference to anyone over any other. It turns out that you cannot do. And the effect that that has when you're trying to calculate probabilities is something like the effect that you get when you try to divide by zero. You, you're doing fine. If you, well, what's, you know, what's 10 over 10? That's 1. What's 10 over 5? That's 2. What's 10 over 2? That's 5. What's 10 over 1? That's 10. What's 10 over 0? Well, the numbers were getting bigger as you went up until you hit 10 over zero. And then it's not there at all. It's not that you get infinity. Division by zero doesn't yield infinity. Division by zero is not defined very important point. The one of the problems that arises when you then you sort of walk in with the entire philosopher's set of assumptions about this and you try to then work the math is you wind up saying that fine tuning and horse tuning are the same in their probabilistic force. So that seems very counterintuitive. It seems counterintuitive to me, even though in reading over John Leslie's formulation of the argument, I was struck by this problem. Still, I'm not saying I don't intuitively feel the tug of the argument, and I'll get back to that in a little while, but the difficulty sort of upfront is you, you can't do it faithfully addressing all of these assumptions simultaneously, which is we're taking a stance of indifference regarding what the universes might be like. Supposing atheism to be true. You know, whatever's logically possible out there is in the mix. We're not giving a preference to any one over any other. It turns out you can't then spread probability evenly like that across the infinite range. That just, that's a no go. It's like taking a finite amount of butter, even continuously divisible butter, and spreading it over an infinite piece of bread. You can't do it smoothly, you know, if there's any at all on some finite chunk of it, then you had infinitely much better to start with. To the extent that I've understood what Luke was saying at the outset, what Luke is saying is, look, that may be an intractable problem. Let's turn our sights on a somewhat different problem as, as a toy case, as a sample case, as a. As a case of something where we can explore this bit. And even though doing so might not answer the original problem which philosophers demand to be solved in all its glory, it may still in some way shed some light on it.

[Dr. Luke Barnes]

Make Apologetics Profile and Watchmen Fellowship your.

[Podcast Host / Narrator]

Go to Resources for answers in Christian.

[Dr. Luke Barnes]

Apologetics, world religions, cults and other non Christian ideologies and spiritual practices, visit our website [e-mail] that's watchmen.org.

[Podcast Host / Narrator]

Luke seemed to agree with Tim's proposition that if one begins with an infinite ensemble of possible universes, deriving any coherent probabilistic data about the values of the constants in our universe is impossible.

[Dr. Luke Barnes]

So I think the fine tuning argument starts with the sort of intuition that Leslie was talking about. Like, you know, you have a century of atheists saying things like Bertrand Russell, you know, we're an accidental collocation of atoms. You know, just chuck anything together Gravity will make it into some planets and then evolution will make it into some people. In here. We, we are, you know, there's, there's nothing special going on around here. And then you look at these actual numbers and you just sort of turn the dial a little bit and suddenly the universe falls apart. You know, the fact that that chemistry happens at all depends on very specific values and, and there's an intuition there. And the question is, how do we, can we build that into something interesting? Not just a. Huh, that's, that's weird. Is there. I think my favorite quote about fine tuning, I think this was said to Alastair McGrath, but it was, I'm not religious, but something weird is going on here. And that's, that captures the, the essence of it. And I think if you're not careful, and I think there's an awful lot of people who weren't careful about how they talked about fine tuning. There's a very. Too quickly, you take that, oh, I turn this dial a little bit and you go, well, of all the possible physical universes, life permitting ones are very unlikely, and you just sort of blew things up a bit too much. No, no, no. We changed a parameter here and a parameter there. Right. We're not, you know, can we, can that shed light on all possible universes? Well, we're going to have to be a bit careful about how we make that case. I think we sort of can. In the same way that a survey of 10,000 people can shed light on who's going to win the next election. You've just got to be careful that you're not, you're not biasing your outcome that you can do something that is possible, like surveying 10,000 people, not everyone, but you've just got to be careful that you're not, you didn't just sort of turn up the, well given, you know, the Republican National Convention and just survey everyone in there. Right. That's no good. So I think so certainly that there's a mathematical problem here that's, that's completely untouchable. You cannot make a probability distribution which is uniform over an infinite range. Can't be done. That's absolutely fine. So if we were trying to do the fine tuning argument that way, that would be a real problem. If you really want an answer to this question, what sort of universe would a naturalist expect if you give up on that question? I mean, on one level, all right, there goes the problem of evil. So, you know, maybe that's worth, maybe it's worth trading those two off. And just getting on with it. Like if, if fine tuning takes out the problem of evil, that might be a win for us in total. Anyway, if you really want an answer to this question, if you want to feel it in your. And I think everyone should, like what, what's going on around here? Is this just any old universe? And I think that the idea of, okay, let's take this sort of physics approach where we just try and find the closest reflective problem that we can solve, right? I can't solve. When I do simulations of how galaxies form, I can't simulate every atom in the universe, right? I just can't. If I could, I'd be basically making my own universe in a computer from scratch with all the details. I just, this just can't be done. So I, I clump my bits of matter together in parts that are, well, for the ones I've been using recently. The Eagle simulation, which I did not write that code, I should not take credit for that. I've just been using their wonderful stuff. It's, it's sort of a hundred thousand times the mass of the sun is one particle, not one atom. It's a hundred thousand suns. But if it's in, in the right way, in the right sort of context, if that toy model, right, reflects the real universe in the right way on the right scales, and we're careful not to over interpret things, then we can use our simplification to shed light on the real problem. And I think that's the spirit of the fine tuning argument. Like we're not changing the laws of nature. We, we could try that, we tried to do that in chapter six of the book. It's just not easy to do systematically. And you know, but, but you know, we're suddenly faced with, we've got these really good, like the standard model of cosmology, standard model of particle physics. They really, they're doing remarkably well, right? There's, there's a finite set of 31 numbers in there. We have a pretty good handle on. There's, there's either dimensionless ones where like standard particle physics practice says, look, they're probably about one, and if they're not of order one, then that's a bit weird. Or there's ones that only vary. You know, there's only a finite range of parameters where we know what the model's telling us or where it only tells us one thing when we ask it one question. And as a setup for, hey, let's make a model that's pretty good in terms of physics, that's we, you know, the naturalist should not just reject that out of hand. I think one of the proofs of this would be if it came out the other way, the naturalists would be shouting this from the rooftops. If over this range, here's the life permitting range, they'd be like, yeah, look, that's what we told you. This was just any old universe, right? The fact that it came out the wrong way, like don't, you know, don't, don't complain about the argument just because it went against you.

[Podcast Host / Narrator]

There is an intuitive sense about the fine tuning parameters, that there is something or someone at work behind the scenes which has fortuitously generated these constants and quantities and that we should not just simply ignore this curious hunch. When, for example, Luke and his colleague Dr. Geraint Lewis toyed around with some of the constants in their computer modeling, it became clear that the life permitting range of these values could not be altered by much before the periodic table of the elements and carbon based life would simply disappear. And as Luke said there at the end, if his modeling had turned out to reveal that the life permitting range were more flexible in its accommodation of carbon based life, naturalists would have championed this as a defeater for fine tuning. So after hearing Luke and Tim lay out the basics of the problem of infinities related to probabilistic fine tuning arguments, I asked them if they agreed with one another about this particular issue.

[Dr. Timothy McGrew]

My sense is that we do. Luke, are you on board with that?

[Dr. Luke Barnes]

Yeah, yeah, yeah, yeah. I can't run the argument by putting a uniform prior probability over an infinite space.

[Dr. Timothy McGrew]

No, I think the difficulty comes in that the way that the argument has been written down in the philosophical literature is very much trying to answer the biggest, the boldest version of the question and all of the formulations of it from that point of view, run into this problem of trying to normalize a distribution that's supposedly flat and across this infinite span. And you, you just can't make that work. So, agreed, we're looking for something else if we still want to find a way to model the intuition that there is something weird going on here. If a paper that Lydia wrote almost 10 years ago on four or so new fine tuning arguments, three at least of which do not seem to run into this problem of stipulating an infinite range and then trying to lay down a uniform distribution on it. So this is part of our attempt to say, look, we're not closed to the sense that there are some very curious, very suggestive things going on here. It's just that we need to be circumspect about the way that we formulate what we're arguing, what we're claiming. And so where we might still have some residual disagreement here, but how much is something that Luke and I think just need to sit down and explore more. It's not that we don't think, wow, this is curious. This is intuitive. There's something that we'd like to be able to catch here. Where I think Luke and I might still sort of have some further discussions to go through is the question specifically, how much do we learn when we render the problem more tractable about the intuitions that originally moved us to try to think about the problem. There are clearly problems that are tractable but trivial. Right. One worry that you can have is, hey, you know what? I created a solvable problem here. Everybody wanders away because they're really not interested anymore in the solvable problem. And so the trick is to come up with something that we think actually sheds at least some light. I think Luke is saying, yeah, it's not going to sort of solve the global problem. If you really stand behind this veil of ignorance in some extremely strongly defined sense, then you may not have a tractable problem at all. Okay, right. You know, and we're on the page. Same page there. But then suppose that we say, well, let's hold quantum field theory and general relativity constant, and let's talk about the possible values that would enable us to get consistent answers from the holding constant of those two theories. That range, as I understand what Luke has told me, and Luke, again, you know, fix me if I screw this up. But that range, it turns out, is finite because we can specify values for those numbers which will then, when we plug them into the equations, give us incompatible results as we approach them with the two different theories. And so that's that. Now we have a logical problem. This is not just saying, oh, I'm myopic. I can't see that far out the number line. I'm not sure what happens out there. This is saying, no, we actually have incompatibilities when we pass this finite value. Now, what that does is that gives us a finite size mathematical target to aim at. And then we can talk completely intelligibly about putting a flat distribution down on it, taking a little chunk of it, saying, well, what percentage is that chunk of the finite bit? So that's. That's a tractable problem. I think it's an interesting problem. The question I'm still a little Fuzzy on. And. And this is just somewhere where I want to do more work is okay, how much do I learn when I learn that? How fussy, in a philosophical sense, should I be about the fact that you left out other universes that don't have those? You know, like. Well, okay, you know, I mean, this. Philosophers are like that. We're just. We're impossible. You know, we want things that it may be. Certainly aren't easy to get answers to. Maybe in some cases we wish we had things and we're just wishing for things that are not out there to be had. Right. Like, oh, I want an answer to this question. Sorry. The way you've posed it, it doesn't have answers.

[Podcast Host / Narrator]

Well, there are some people in your profession, Tim, that when they get together at conferences, they're not even sure they're in the same room together.

[Dr. Timothy McGrew]

Well, that depends on whether it's happy hour and just how much fun they've been having.

[Dr. Luke Barnes]

To. What Tim said. I think that's about right. Yeah, There's. There's a. This sense of, like, okay, we have this intuition of, you know, you see a. You see a hummingbird and you're like, that's pretty amazing. And then you think the. The weirdness starts with the fact that we're amazed by the only universe we've ever seen. And like, okay, now what.

[Podcast Host / Narrator]

Right.

[Dr. Luke Barnes]

Should I do something with that fact? We're amazed by the only universe we've ever seen. Well, and then Leslie has a very good point where it's like, you don't have to go wandering through other universes just to. Just to keep that amazement. Right. The fact that you've only ever seen one universe still doesn't. Doesn't quite push away that feeling. And I guess the problem. Just going back to it, the problem of evil would then be something like, well, there's too much evil in the only universe we've ever seen. Well, we, you know, so there are. There's very, very big questions there. When you start to say, well, what else. What else could the universe have been like? And then you're at the. The mercy of all these other logical possibilities. And that space is unbelievable. Like, just forget it. Like, we're not gonna. I'm not gonna throw down my probability distributions over that space. Well, are we just done? Do we just give up and that. So the spirit here is just, well, let's just try this one. Let's try this. Let's. Let's vary these constants and see what happens. This is a fair way to approach the problem.

[Dr. Timothy McGrew]

This sounds like a clickbait headline. Try this one weird trick to lose weight or something.

[Dr. Luke Barnes]

There's one weird trick at the bottom.

[Podcast Host / Narrator]

Of your newsfeed with the lemons in the boiling pot.

[Dr. Timothy McGrew]

Yeah, right, right, right. Yeah.

[Dr. Luke Barnes]

I think the natural would be shouting from the rooftops if we turned out to be a typical, just any old universe, given the approach that, that fine tuning takes. But it doesn't turn out that way, it turns out the other way, in which case you can't just sort of throw out the results after you've, you know, you don't like the answer if you've, yeah, if you do it that way, what does the multiverse give you? The multiverse just raises a possibility that there might be deeper physics than what we know about. And then you really should be asking the question, hey, all right, there's the naturalism door. There's a multiverse behind that door. What sort of multiverse do you think might be back there? And you're back in the unsolvable problem thing. So for me, it's the equivalent of taking your bat and ball and going home. Right. I, I didn't like what turned out, so, but I, I, we have no chance, like, I've, we've crafted out this, we can put this probability on this parameter because we've got this, we've done these, you know, simulations and calculations and hard work being done, and it didn't turn out very nice. Well, what if there's other physics where I have no clue whether our universe is typical or atypical, what sort of multiverse might turn up and that it's just sort of a, you know, what if, you know, what if we couldn't do this calculation again? You know, what if we didn't have something representative? What if we had no clue whether what sort of multiverse might turn up? And for me, it's that sort of response. In which case, look, if you're going to be skeptical, just, just say you're going to be skeptical. Don't throw it behind this sort of, you know, facade of, oh, I'm doing more cosmology. So that's my problem with the multiverse.

[Podcast Host / Narrator]

In 2021, on the podcast Unbelievable Then, hosted by Justin Brierly, Luke had a discussion with atheist and physicist Dr. Sabina Hossenfelder about the fine tuning of the universe. Dr. Hossenfelder argued that the probabilities are only based on information we already know and that she believed the constants invoked in fine tuning arguments don't require any deeper Explanation. Here's what she said.

[Dr. Luke Barnes]

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 for my purely observational point of view, I don't think we have any reason why there has to be this deeper explanation. And, and let me say again, you know, it, I, 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 son of using 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 we currently know, it just doesn't have to be the case.

[Podcast Host / Narrator]

Luke told me Sabina approached the probability question not from the perspective of a Bayesian formulation, but from what is called finite frequentism. In the simplest of terms, think of finite frequentism as dice rolling. We can roll dice and record outcomes and then ask questions like, given a pair of dice, what's the probability that I'll roll a 7? But of course, as you can imagine, we cannot roll universe dice to see what sort of outcomes would permit life. So from Sabina's perspective, it is pointless to ask what the probability of the existence of our universe might be as we can't test it it. But as Luke shared with me, this is really not a fatal objection to fine tuning as Bayesian reasoning is a huge part of research in contemporary physics.

[Dr. Luke Barnes]

Her response is, you don't have these probabilities because probabilities just describe data you already have. That's all they do. That's the finite frequentist approach. And I think that's just like there's a long story of why she's taking that point of view. Because taking a wider point of view with probabilities, the sort of Bayesian sense leads to these, these sort of arguments in particle physics about the sort of things we would expect to see when the next generation of particle accelerators fires up. You know, we'll see super symmetry. It doesn't matter what supersymmetry is, it's just going to be there when we build this, the next new thing. And a lot of on the basis of arguments that look a lot like fine tuning arguments, they're not about life, but they have a similar sort of shape. And her objection was, look, we've put way too many eggs in this basket. This fine tuning stuff is really just an appeal to sort of beauty and symmetry and simplicity where we don't, we don't know what the universe is really doing. So we should be putting our eggs in more different baskets, not just putting it all on the Large Hadron Collider in underneath Europe. So there's a, there's a, there's a long story behind that. But where then fine tuning argument turns up and it combines all that type of argument she doesn't like with God, who she's not a fan of either. So it's sort of, but that's why she's not a fan of it. The objection, the reply to be, look, I mean, last time I checked, there were around about 20,000 papers in physics and astronomy journals that have the word Bayesian in the title of the paper. Not just used, not just this approach used in the paper. So important and integral to the paper itself that it's in the title.

[Podcast Host / Narrator]

Right.

[Dr. Luke Barnes]

They, they felt the need to tell the, you know, that this is a Bayesian approach to this or that or whatever. I think you just can't throw this sort of approach away. Like it's just too useful. Too many scientists doing, too many different types of scientists think that this approach is, is, is a, is a good way to approach probabilities here.

[Podcast Host / Narrator]

I asked him about why the Reverend Thomas Bayes did not theory in his lifetime, and I asked him to comment further on Bayesian versus finite frequentism.

[Dr. Timothy McGrew]

I don't think he had any questions about the legitimacy of what he was doing. He passed it to his friend Richard Price, who did eventually communicate it on and get it published. But it was a kind of recondite problem in the doctrine of chances. He was asking, you know, we all know that if you have an urn and you draw out this many balls and there's this percentage of black balls among them, that that gives you some sense of, or if you have an urn that has a certain proportion of balls, then we know what sorts of things you might expect to be drawing from it. But given that you've drawn certain things, what should you think about the urn? The inverse kind of problem is it's not reasoning from hypothesis to observation, it's reasoning backward from observation to the hypothesis. And it's a tricky problem. The terminology in which Bayes himself formulated it would not look familiar to us today, but down there at the root of it. Yeah, I Mean, he's, he's uncovered something that is. Now, it's widespread, not because Tom Bayes is a great guy, but because it turns out that any kind of normal probability theory done in the real number system has that just down at near the base as a theorem. It is just a, it's a way of coordinating these things that we call probabilities. And if you violate it, you wind up saying, you know, there's a 5% probability that the Steelers will win the super bowl, but a 99% probability that they won't. And those don't fit. You can't, like you violate these, you know, any theorem of probability and you wind up with these impossible things that you can't fit back together. It's the probabilistic parallel to logical inconsistency. So we call it incoherence. So now Luke's absolutely right. It's used all over the place in science, but most particularly in astrophysics. Astrophysics today is just, I think, not even conceivable without the use of Bayesian tools. Many of those papers are not spanning across infinite sets and trying to lay down, you know, flat distributions across them. That's, that's not what they're doing. They're not even concerned with fine tuning at all. They're concerned with things like, you know, large scale structures in the universe and stuff like that. You know, fascinating stuff, Good stuff, love it. The point is simply that this kind of inverse reasoning, the reasoning, if I may vastly oversimplify it, it's often a reasoning from effects to causes rather than from causes to effects, that, that is widespread because it turns out to be the indispensable mathematical tool insofar as you have a mathematically tractable subject matter at all for coordinating your reasoning to look at evidence and move backward towards theory, try to try to figure out the way stuff is, which is, after all, very major goal. So yeah, that's, that's all over. In the literature it is used. I think that's a good thing, not a bad thing. So, you know, three cheers for Bayesian probability. So why are people still grousing around about the frequentist kind of stuff? I think one of the reasons is this a big question and a fair question anytime you are employing Bayesian equations is where did you get your initial numbers? And it turns out that if you're really going to push that question hard, you can't just say, well, I got them from a previous probability distribution by Bayes theorem. And so did that, and so did that. And it's Turtles all the way down. Eventually people want you to ground some of these numbers in some observations where we can count this stuff, which is good, like that the numbers should not fly completely free so that I can just make up some numbers based on how I feel after breakfast and then expect anyone else to be interested in them. There should be some kind of empirical tie downs. So some of the inputs that we use when we begin to turn the crank on the Bayesian machinery are inputs that do come from other kinds of statistical analyses. That's not a problem. That's, that's not a concession. That Bayes theorem is nothing. That's not a, you know, it's not a capitulation to the frequentists because we all know. So the standard joke about Bayesian frequentists is that Frequentists use rigorous mathematics to answer questions nobody was really interested in. Whereas the Bayesians give us definite numerical answers to the questions we really wanted answered by means of assumptions nobody quite believes. That's the, that's the joke. Right. But the, the fact is, yeah, we need to, you know, we need to look at the stuff that we can count and we need to be measuring things and pulling some of our probabilities, or at least approximate rough back of the envelope level probabilities, like Luke was saying. Well, either these things are about one or something weird is going on. Right. So we, you know, we want to have some probabilities that are grounded in our observations, but then questions arise. Okay, now what if we had a theory that laid down these expectations and we took the observations we've got and we try to put things together. This is an enormously powerful tool. Everybody should use it. I spend a non trivial portion of my philosophical life trying to induce students, trying to get them to think Bayesianly so that no problems with the math, no aspersions on the math and no sneering at frequencies when they're available and can be used for input. Yeah, we'll use them. Right. So anyway, that's, that's my take on it.

[Dr. Luke Barnes]

Yeah, I think the idea here is that, you know, often in science, in philosophy, in life, you're faced with uncertainty and you could just say I don't know and then go home. And you know, that would be, that would be, I guess, you know, defensible. You don't know. But the whole point of probabilities is that we can use them to understand cases where, you know, we can do better than just saying I don't know. So if you have a, you're playing, you know, whatever you're playing poker, right? You know, what, what's the probability of me winning this hand if I go all in, right? You can just say I don't know and then just go for it, or you can actually start to do some numbers and try and work it out and do some math. So the point here is that the, I don't know, we come up against here is what sort of universe would you expect to turn up if naturalism was true? If naturalism was true, this is just a naturalistic universe. Would, you know, would we expect to be in this sort of universe or something else? And you can say, I don't know. Or you can say, well, let's, let's, you know, we've. Naturalism likes, you know, laws of nature and stuff, and there's these constants and we've got Bayesian probabilities. Let's just try and put a whole thing together like, and we'll see whether our conclusions are robust and we'll see whether we think they really reflect the big problem we wanted to solve. And we can think through all of those things. But this is not an un, you know, it's not a bespoke, you know, made up on the spot approach by theists trying to make an argument out of nothing. This is just like, this is the most natural thing in the world for me, if I want to know. I've got some observations of a distant, you know, galaxy and I fire, you know, I put a camera and they hit the camera. I've got to worry about things that hit the camera that didn't come from the galaxy, like things, even things that aren't light, like cosmic rays. And you just, like, you just say, I don't know whether any of this is cosmic rays or light and you go home. Or you can try and model the thing and deal with it and deal with outliers like this. There's just a lot we can do. And when you take those sorts of approaches to this question of naturalism and is this any old universe, the fine tuning gives us a very, I think, interesting and tractable. Both of those things have got to be true, right? Interesting and tractable scenario.

[Podcast Host / Narrator]

A deeper question we might ask is why does Bayesian probability reasoning even work within this universe? In other words, why is the universe actually intelligible to us? And why does our mathematical reasoning seem eerily to cohere with what we observe all around us? The late quantum physicist Eugene Wigner, for example, marveled that mathematics was so integral and useful for science. In his landmark paper, the Unreasonable Effectiveness of Mathematics in the Natural Sciences. He noted with not a little astonishment, the miracle of the appropriateness of the language of mathematics for the foundation of the laws of physics is a wonderful gift which we neither understand nor deserve. Cosmologist Alexander Vilenkin, at the end of his 2006 book Many Worlds in One, pondered that it follows that the laws should be there in the. Even prior to the universe itself. Does this mean that the laws are not mere descriptions of reality and can have an independent existence of their own? In the absence of space, time and matter, what tablets could they be written upon? The laws are expressed in the form of mathematical equations. If the medium of mathematics is the mind, does this mean that mind should predate the universe? End quote. For Tim, the intelligibility of the universe is the marvelous thing.

[Dr. Timothy McGrew]

So the intelligibility is a matter of the fact that we can write down a few equations and get a grip on so much. Now that's fascinating. I think that. All right, that. Now that's. That that keeps me up at night.

[Podcast Host / Narrator]

Luke here also interjected that he believed if naturalism were true, one should not even expect there to be any laws of nature at all.

[Dr. Luke Barnes]

Yeah, I mean, it's a completely separate argument, but I'm coming around to this, that I don't think there's any reason the naturalists can give to expect there to be laws of nature at all. But that's a, that's a drive by at the end, just, just for the f.

[Podcast Host / Narrator]

Hopefully we have shed some intuitive and edifying light on what are often intimidatingly dense and difficult topics. It is not often you get a physicist and a philosopher to sit down for an informal chat about these things, let alone discourse about them in an understandable and entertaining sort of way.

[Dr. Timothy McGrew]

This was fun and, and I think we kind of, you know, we rambled across the terrain as well. As a physicist who is. Finds his leg tied to a philosopher can do. Luke has moved like past the point of saying, oh, you know, that's a problem. He's like, yeah, you're right, that's a problem. Now we all start with the intuition, so why would you just throw that away? Okay, if this way of formulating it isn't going to be tractable, let's look at something else. And I think that's fair.

[Podcast Host / Narrator]

As we were wrapping up, Luke jumped in and surprised us with an unrelated last minute request to share with Tim and me a chart he'd recently put together about existing biblical manuscripts. It is a cleverly animated timeline of dates of extant ancient manuscripts on one axis and verses in the Bible on the other. Luke's chart shows how and when verses in the Bible correspond to existing manuscripts we originally conversed over.

[Dr. Luke Barnes]

Zoom.

[Podcast Host / Narrator]

So here in the audio, you won't be able to see the chart, but as Luke explains it, you can hopefully at least somewhat visualize it.

[Dr. Luke Barnes]

Okay, let me set this up. This is totally left field for me at Matthew. Matthew Tingblad, he just made a. He had a video a while ago where he and another colleague, whose name I forget, they have this enormous spreadsheet which has all the manuscripts of the New Testament and then all of the verses of the New Testament, this enormous thing, and is that verse in that manuscript? He then sort of had this Excel plot, and I went, oh, I could have some fun with this. So on the X axis, you can see this plot, right? It's. It's the year. And on the Y axis is of all the verses in each of the gospels in Acts, how many of them can you find in a manuscript before that year? Right. So there goes Matthew, and then about 200, John and Luke take off, and then Acts takes over a little bit, and then up we go. Now we should pause there at about 300 to 350. You've, of course got the Sinaiticus and Vaticanus, which. So all these should really just shoot to 100% by then. But ignoring those, if Sinaiticus and Vaticanus were in this, every line would jump to 100. Yeah, this is everything else. Otherwise the. The lines after 350 would be boring and just. They'd just be across the top. So all of this is, like, sort of academic, I suppose. But anyway, I'm now wondering whether this is interesting to anyone. I had some fun.

[Podcast Host / Narrator]

After Luke's delightful demonstration, Tim jumped in with his own expertise on biblical manuscripts.

[Dr. Timothy McGrew]

Because what we're looking at here is not, you know, when were these things written about? It's what do we have dating back to that date or before, by our best estimation, that we're looking at here on the. On the graph. And so that's fascinating because history isn't kind to papyrus, you know, that you have to have. Even in Egypt, where we have some papyrus. It's. It's only in very special places in Egypt. It's not where it's all muddy. It's. It's where you've got dry sands. And this stuff can just be preserved in it for aeons. But most, most of what was written.

[Podcast Host / Narrator]

We don't have at this point in the conversation. I was rather delighted we had ended up talking about the Bible, as it seemed to me the Lord gently interrupted and desired to have the final say, as he often does. So I asked both Tim and Luke here how they might connect fine tuning arguments to the God of the Bible.

[Dr. Timothy McGrew]

The super short answer is just, we have more data than we were working from for just the fine tuning, right? I mean, we do have, you know, these, we have these manuscripts, they were written by someone. They, they, you know, purport to give us reports of certain things. What are the tools by which we investigate these kinds of things that are good, sound, reasonable canons of historical inquiry. And so you widen your field of data, is, is my short answer to that. And when you widen your field of data, then you are in a position to do more.

[Dr. Luke Barnes]

Yeah, my, my thing is if you read the New Testament and you're convinced there's no God, right? But you know, it's not going to do. It might not do much to you. It might, but, you know, but so if, if you read it thinking, you know what the, the amazing things I see is nature really could be because there's a God behind this whole thing. And then you read the New Testament, right? So I'm quite happy to say, look, fine tuning could be an argument for Islam. You know, that's fine. Just, you know, we're going to need more evidence than that. But it's out there, so go look at it. Go read the New Testament.

[Podcast Host / Narrator]

As we wrapped up, I mentioned a recent quote I have read from historian and popular science fiction writer H.G. wells, who was himself an atheist. In a July 1922 edition of the American Magazine, Wells noted that when conducting a comprehensive survey of history, one could not overlook Jesus of Nazareth. Wells said that of course, you and I live in countries where to millions of men and women, Jesus is more than a man. But the historian must disregard that fact. He must adhere to the evidence which would pass unchallenged if his book were to be read in every nation under the sun. Now, it is interesting and significant, isn't it, that a historian setting forth in that spirit, without any theological bias whatever, should find that he simply cannot portray the progress of humanity honestly without giving a foremost place to a penniless teacher from Nazareth. We here at Watchman Fellowship routinely engage with a multitude of other religions and cults, and most of these groups do indeed have something to say about Jesus. He is, after all, the suffering servant of whom Isaiah prophesied. He is the man of sorrows, acquainted with grief. He is the one whom John equated with God, the Word made flesh, who made everything. He is the way, the truth, and the life. He is the one whom the Apostle Paul tells us in Colossians created the universe, the very one whom the writer of Hebrews tells us upholds the universe by the word of his power.

[Dr. Luke Barnes]

Apologetics Profile is a production of Watchman Fellowship, Incorporated in Arlington, Texas. For more information about the ministry of Watchmen Fellowship, visit our [e-mail] that's watchman with an A dot org. You can also email Daniel Ray, the.

[Dr. Timothy McGrew]

Host of Apologetics Profile Wray, at Watchman.

[Dr. Luke Barnes]

Org. That's D R a [e-mail] he would love to hear from you.