Defenders: Excursus on Natural Theology (Part 16): The Teleological Argument Part 3

Summary

Defenders Podcast: Excursus on Natural Theology (Part 16)

The Teleological Argument Part 3 — July 28, 2022

Host: Dr. William Lane Craig

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Overview

In this episode of the Defenders Podcast, Dr. William Lane Craig continues his in-depth examination of the fine-tuning version of the design (teleological) argument for God’s existence. The focus is on critically evaluating alternative explanations for the precise constants and boundary conditions observed in our universe—specifically, the chance hypothesis and its relationship to the multiverse (many worlds) proposal. Dr. Craig uses accessible analogies and detailed objections, aiming to clarify why chance (with or without a multiverse) is ultimately unconvincing, thus setting the stage for further defense of design in subsequent classes.

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Key Discussion Points & Insights

1. Review of Fine-Tuning and Its Explanatory Alternatives

[00:08–01:48]

• The universe’s fundamental constants and boundary conditions are fine-tuned to a "delicate and incomprehensible" degree for embodied conscious life.
• Three general explanations considered:
  • Physical necessity: Constants must be as they are (already dismissed as highly implausible).
  • Chance: Life-favorable settings occurred randomly.
  • Design: An intelligent cause set them.
• Quote: “The best evidence indicates that these constants and quantities are independent of the laws of nature and that there is nothing physically that would determine that they should have the finely tuned values that they do.” (Craig, [00:42])

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2. Examining the Chance Hypothesis

[01:48–08:08]

• The “chance” alternative suggests that, against astronomical odds, the universe is life-permitting by sheer accident (“we just lucked out”).
• Objection raised: some argue it's meaningless to speak of the probability of our universe—since only one exists.
• Dr. Craig responds with physicist John Barrow’s dot-on-paper analogy:
  • Minor tweaks to constants produce a vast “sea” of non-life-permitting (“black dot”) universes, with only very few life-permitting (“red dot”) exceptions.
  • Quote: “There are simply many more life prohibiting universes than life permitting universes in our local area of possible universal universes.” (Craig, [03:14])

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3. Clarifying Probability with Lottery Analogies

[04:10–10:23]

• Critics use a lottery example—though improbable, some ticket must win.

• Craig distinguishes between explaining why a specific person wins vs. why a type of winner occurs (i.e., a life-permitting universe).

• Improved analogy: Billions of white ping pong balls (death) and just a couple of orange ones (life-permitting). Any specific draw is improbable, but drawing an orange one (life) against overwhelming odds is what must be explained.

  • Choosing orange five times in a row would make chance a poor explanation—design is suspected.

  • Quote: “The relevant point rather is that whichever ball rolls down the chute... it is incomprehensibly more probable that it will be white rather than orange. So if the orange ball does roll down the chute, allowing you to live... you certainly should suspect that the lottery was rigged.” (Craig, [06:18])

  • Memorable Expansion: “If five times in a row the orange ball came down... everyone would recognize that it did not happen by chance, that somehow this was rigged.” (Craig, [07:43])

• Q&A with Bruce and George: Bruce observes (10:23) that highly specific selection criteria would further heighten suspicion of rigging; George (11:14) points out that not all lotteries must have a winner, paralleling the philosophical point that a universe need not exist at all.

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4. Anthropic Principle & Its Limits

[13:23–16:22]

• Some argue no explanation is needed for a life-permitting universe—since only in such universes could observers exist (the anthropic principle).
• Craig rebuts: This doesn’t explain why such a universe exists—it only explains the conditional limit of observation.
• Firing squad analogy:
  • 100 marksmen fire at you; all miss. You’re alive, but mere survival doesn’t remove the need for an explanation.
  • Quote: “You should still be surprised that you do observe that you are alive — in light of the enormous improbability of all 100 marksmen missing. In fact, you’d probably conclude... that the whole thing was a setup engineered for some reason.” (Craig, [15:24])

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5. The Multiverse (Many Worlds) Hypothesis

[17:18–21:29]

• The conjunction of the anthropic principle with the multiverse is offered to eliminate surprise at fine-tuning.

• In an infinite set of universes, everything happens somewhere—including life-permitting conditions.

• According to Craig, this proposal is "extraordinarily extravagant" and possibly adopted solely to avoid design.

  • Quote: “Otherwise sober scientists would not be flocking to adopt so speculative and extravagant a view as the many worlds hypothesis unless they felt absolutely compelled...” (Craig, [19:14])
  • Survey Highlight: Over 50% of cosmologists surveyed by Neil Manson said their peers believed in the multiverse partly to avoid cosmic design. ([21:29])

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6. Critiquing the Multiverse Hypothesis

[22:39–35:18] Dr. Craig raises three main objections:

a. The Multiverse Needs Fine-Tuning Too

• Any universe-generating mechanism must not itself require fine-tuning; otherwise, it hasn't solved the original issue.
• The proposed mechanisms (e.g., M-theory, superstring theory) are vague and do not clearly eliminate the need for fine-tuning.

b. Lack of Independent Evidence

• There is no evidence that such a world ensemble exists, let alone one that is randomly ordered and infinite.
• George Ellis (leading cosmologist): The multiverse hypothesis is not scientifically provable.

c. Boltzmann Brains and Probabilistic Catastrophe

• Drawing on Roger Penrose: If our universe is a random member of a vast ensemble, it’s far more probable we'd observe a much smaller, less ordered world—perhaps only a “Boltzmann brain” (a self-aware entity spontaneously arising).
• Quote (Penrose via Craig): “The odds of our universe’s initial low entropy condition existing by chance alone is... one chance out of 10 to the power of 10 to the power of 123, a truly incomprehensible number.” ([28:56])
• Craig’s punchline: “No sane person believes that he is a Boltzmann brain on atheism.” ([32:49])
• Irony: The only way for the multiverse to avoid this absurdity is to posit a God ordering the universes—a “backhanded compliment” to the design hypothesis.

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7. Concluding Implications

[35:40–End]

• With the collapse of both physical necessity and chance (even with many worlds), the door is left open for design as the remaining explanatory candidate for fine-tuning—setting up the next lesson.

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Notable Quotes (With Attribution & Timestamps)

• "The best evidence indicates that these constants and quantities are independent of the laws of nature and that there is nothing physically that would determine that they should have the finely tuned values that they do."
  — William Lane Craig, [00:42]

• "There are simply many more life prohibiting universes than life permitting universes in our local area of possible universal universes.”
  — William Lane Craig, [03:14]

• "But that point is irrelevant because we're not trying to explain why this particular ball was picked. The relevant point rather is that whichever ball rolls down the chute, it is overwhelmingly… more probable it will be white rather than orange.”
  — William Lane Craig, [06:30]

• “If five times in a row the orange ball came down... everyone would recognize that it did not happen by chance, that somehow this was rigged.”
  — William Lane Craig, [07:43]

• “You should still be surprised that you do observe that you are alive — in light of the enormous improbability of all 100 marksmen missing…”
  — William Lane Craig, [15:24]

• "Otherwise sober scientists would not be flocking to adopt so speculative and extravagant a view as the many worlds hypothesis unless they felt absolutely compelled..."
  — William Lane Craig, [19:14]

• “No sane person believes that he is a Boltzmann brain on atheism. Therefore, it's highly improbable that there exists a randomly ordered world ensemble."
  — William Lane Craig, [32:49]

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Important Timestamps

• [00:08] Main theme: Explanations for fine-tuning
• [03:14] Barrow dot analogy for fine-tuning probability
• [06:18] Ping pong ball/life-permitting analogy
• [10:23] Q&A: Lottery analogy variations
• [15:24] Firing squad/anthropic principle analogy
• [19:14] Multiverse as a response to fine-tuning
• [21:29] Sociological survey on motivations for multiverse belief
• [28:56] Penrose’s statistical critique (Boltzmann brain problem)
• [32:49] The irony: The multiverse needs God
• [35:18] Concluding observations and next class preview

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Tone & Style Notes

Dr. Craig’s approach is logical, patient, and explanatory, favoring analogies and careful distinctions over polemic. Audience interaction is respectful and clarifying; answers are thorough. The tone is earnest, pedagogical, and occasionally light when dealing with outlandish objections ("Boltzmann brains... reminiscent of a 1950s grade B horror movie").

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Summary

Dr. Craig demonstrates that neither physical necessity nor chance—either alone or via the multiverse—adequately explains the fine-tuning of the universe for life. He argues that these alternatives either fail scientifically or collapse under their own philosophical weight, often requiring even more extravagant assumptions, and ironically, perhaps even theism to avoid their most absurd implications. The design hypothesis remains the standing candidate for future discussion.

Transcript

[A]

Welcome to Defenders, the teaching class of

[B]

Dr. William Lane Craig.

[A]

Today an excursus on Natural Theology, Part 16. For more resources from Dr. Craig, go to reasonablefaith.org today we want to continue our discussion of the design argument for God's existence based upon the fine tuning of the universe. We saw that the fundamental constants and boundary conditions of the universe are fine tuned for the evolution and existence of embodied conscious agents in a degree that is incomprehensible and incomprehensibly delicate, as well as complex. And there are three explanations for this incredible fine tuning available in the literature. One is physical necessity, that the constants and quantities have to have the values they do. The other is chance, and the third is design. Now we've already seen that the first alternative, that this is a matter of physical necessity, is highly implausible. This is contrary to the best evidence of science. The best evidence indicates that these constants and quantities are independent of the laws of nature and that there is nothing physically that would determine that they should have the finely tuned values that they do. So that leads us then to the second alternative, and that is chance. Could the fine tuning of the universe just be the result of chance? Now, according to this alternative, it's just an accident that all of the constants and quantities fall into the infinitesimal life permitting range. We just basically lucked out. The fundamental problem with this explanation is that the chances of of a life permitting universe's existing are so remote that this alternative becomes unreasonable. Now sometimes people will object that it's meaningless to speak of the probability of a fine tuned universe as existing, because there is after all, only one universe. And so you can't say, for example, that one out of every 10 universes is finely tuned to be life permitting. Now I've already addressed that question in our discussion time, but I do want to go through it again just to cement the point. John Barrow, who is Cambridge University physicist, gives the following illustration of the sense in which it can be said that that it is highly improbable that a finely tuned universe should exist. Barrow said, let's imagine a sheet of paper and put on it a dot representing our universe. Now alter some of the fundamental constants and quantities by just tiny amounts and that will then be a description of a new universe. If that universe is life permitting, make it another red dot. If it's life prohibiting, we'll make it a black dot and then do it again, do it again, do it again, do it again, do it again until your sheet of paper is Filled with dots. And what you wind up with is a C of black with only a couple of pinpricks of red in the field. And it is in that sense that it is overwhelmingly improbable that the universe should be life permitting. There are simply many more life prohibiting universes than life permitting universes in our local area of possible universal universes. Now, sometimes people will appeal to the example of a lottery in order to justify the chance alternative. In a lottery in which all of the tickets are sold, it is fantastically improbable that any one person should win the lottery. And yet somebody has to win if all the tickets have been sold. And so it would be unjustified for the winner, whoever he might be, to say something like, well, the odds of my winning were 20 million to one. The lottery must have been rigged to make me win. Now, in the same way these people will say some universe out of the range of possible universes had to exist. And the winner of the universe lottery would also be unjustified if he thought that because his universe exists, this must have been the result of design and not chance. All of the universes are equally improbable. And yet some universe had to exist. And so the one that does exist would exist simply by chance alone. And it would be unwarranted to conclude that that it was a result of design. Now, this lottery analogy is actually very helpful because I think it enables us to see where the objector has gone wrong, where he has misunderstood the argument from fine tuning, and then to offer a better and more accurate analogy in its place. Contrary to popular impression, the argument for design is not trying to explain why this particular universe exists. Rather, it's trying to explain why a life permitting universe exists. The lottery analogy was misconceived because it focused on why a particular person won. The correct analogy to the fine tuning argument was would be a lottery in which billions and billions and billions of white ping pong balls were mixed together with just say one or two orange ping pong balls. And you were told then that one ball will be randomly selected out of this hoard. If it's orange, you'll be allowed to live. If it's white, you'll be shot. Now notice that any particular ball that is chosen is equally improbable. No matter which ping pong ball rolls down the chute, the odds against that particular ping pong ball will be fantastically improbable. But some ball must roll down the chute. And that's the point that's illustrated by the first lottery analogy, somebody has to win. And just because that particular ball is highly, highly improbable would not justify a design inference. But that point is irrelevant because we're not trying to explain why this particular ball was picked. The relevant point rather is that whichever ball rolls down the chute, and it is overwhelmingly, incomprehensibly more probable that it will be white rather than orange, getting the orange ball is no more improbable than getting any particular white ball. But it is incomprehensibly more probable that whichever ball you get, it will be white rather than orange. So if the orange ball does roll down the chute, allowing you to live in, you certainly should suspect that the lottery was rigged to let you live. Now, if you don't see the point of this analogy, imagine then that the ball, the orange ball rather or an orange ball, had to be picked five times in a row randomly in order for you to live. If the odds against the orange ball being picked even once are great enough, having it happen five times in a row won't materially affect the probabilities. But obviously if such a thing happened, if five times in a row the orange ball came down the chute, everyone would recognize that it did not happen by chance, that somehow this was rigged. So in the correct analogy, you're not interested in why you got the particular ball that you did, rather were puzzled by why against overwhelming odds, you got a life permitting ball rather than a life prohibiting ball. And that question just isn't addressed by saying, well, some ball had to be picked. And any particular ball is equally improbable. So in exactly the same way, some universe has to exist. But whichever universe exists, it is incomprehensibly more probable that it will be life prohibiting rather than a life permitting universe. So we still need some explanation as to why a life permitting universe exists. Any question about that analogy and which one is appropriate to the argument? Yes, Bruce. And we'll get you the microphone here, Bruce, so that we can all here

[B]

to comment more on the objector's analogy of a that something had to be chosen. You could say, yes, one has to be chosen, but what about if you had the conditions that the person selected to win the lottery also had to be a 46 year old male, 5 foot 10, 195 pounds, and on and on and on.

[A]

Yeah, I used life permitting, but William Dembsky, I think used an example of what if every time the lottery was won, it was won by someone who was a member of the mafia. Wouldn't you get a little bit suspicious? And so it's kind of similar here. Why is it that against all the odds, it's a life permitting universe that exists? Okay, thank you. Yes, George?

[C]

Bill, on the lottery analogy, don't you think it's not the case that the lottery that some lottery player has to win? I think in like the Powerball that we just saw last week, it could be that nobody matches all the numbers, so nobody wins and the jackpot rolls over. So on the universe side of the discussion, it could be that no universe would exist. So it's not that some person had to win. Somebody has to match all the numbers in order to win, and that may

[A]

not happen at all. I used the analogy of a lottery in which all the tickets are sold so that a winner is guaranteed of buying the winning ticket.

[C]

That's a different kind of game though.

[A]

Yeah. And the reason I did that is because if you say, well, it's not true that some universe has to exist, there could have just been nothing. It seems to me that that kind of bleeds over into the Leibnizian cosmological argument asking why is there something rather than nothing? And that's a great question. Why does a contingent universe exist at all? Couldn't there have been nothing? But just for the sake of argument, to keep the fine tuning argument as independent from these other arguments as possible, I was willing to concede for the sake of argument that some universe had to exist. But as you say, that's not true. If the universe is a contingent being, it didn't have no universe, had to exist. Yes, way in the back.

[C]

Isn't it true that there really is no true random lottery, that they use some mathematical algorithm that I guess can be solved? That is that the case that you could reverse engineer any lottery? I thought I read about that.

[A]

I haven't read about that. I mean, in one sense, when we're talking about winning by chance, we don't mean that it's indeterministic. I mean, obviously there are factors that cause which ball to be chosen than some others. So you're dealing with a deterministic situation here. I think that's true. Unless you believe in quantum indeterminacy and had some sort of quantum indeterminacy device be responsible for selecting the winning ball. But if you're dealing with ordinary classical physics, then you're quite right in saying that it's by chance only in the sense that independent causal lines come together to produce the effect, but not that it is uncaused or Literally indeterminate. All right, let's proceed then. Some people have argued that no explanation is needed for why we observe a life permitting universe, because that's the only kind of universe we could observe. If the universe was were not life permitting, then we wouldn't be here to ask about it. This is the so called anthropic principle. The anthropic principle which says that one can observe only properties of the universe which are compatible with our existence. Obviously it would be impossible for us to observe properties of the universe incompatible with our existence because we wouldn't be there. So the anthropic principle says you can only observe properties of the universe which are compatible with our existence. And therefore since you observe those kind of properties, you shouldn't be surprised about it. There's no explanation necessary. Now this reasoning is fallacious. The fact that we can only observe life permitting universes does nothing to explain why a life permitting universe exists. The fact that that's the only kind we can observe doesn't remove the need for an explanation of why such a universe does exist. And again, illustration can help here. Suppose you're traveling abroad and and you're arrested on trumped up drug charges and dragged in front of a firing squad of 100 trained marksmen at point blank range. All of them with rifles aimed at your heart. You hear the command given, Ready, aim, fire. And you hear the deafening roar of the guns. And then you observe that you're still alive. That all of the 100 marksmen missed. Now, what would you conclude? Well, I guess I really shouldn't be surprised that they all missed. After all, if they hadn't all missed, I wouldn't be here to be surprised about it. Given that I am here, I should expect them to have missed. Well, of course not. It's true. You shouldn't be surprised that you don't observe that you are dead, because if you were dead, you wouldn't be able to observe it. But you should still be surprised that you do observe that you are alive. In light of the enormous improbability of all 100 marksmen missing. In fact, you'd probably conclude if this happened, that they all missed on purpose, that the whole thing was a setup engineered for some reason by someone. And therefore theorists have come to recognize that the anthropic principle will not eliminate the need of an explanation of the fine tuning unless it's conjoined with a so called many worlds hypothesis or multiverse hypothesis. According to the many worlds hypothesis, our universe is is just one member of a World ensemble of parallel randomly ordered universes, preferably infinite in number. And often this ensemble is called the multiverse. Now, if all of these other universes really exist, and they are randomly ordered in their constants and quantities, then then by chance alone, life permitting worlds will appear in the ensemble. And since only finely tuned universes have observers in them, any observers existing in the world ensemble will naturally look out and observe their worlds to be finely tuned. And so the claim is no appeal to design is necessary in order to explain fine tuning. So the conjunction of the anthropic principle with the many worlds hypothesis or multiverse is said to eliminate the surprise that we have at observing a finely tuned universe and any need of an explanation beyond sheer chance. Given that there's an infinite number of parallel universes and that they're randomly ordered in their constants and quantities of life permitting worlds will exist in the ensemble. And only such worlds will have observers in them. So of course the observers see their world to be finely tuned. Now, before I comment on the world ensemble hypothesis, let's just be sure we all understand it, how it is an attempt to rescue the alternative of design and how it explains the fine tuning of the universe that we observe. Is there any comprehension type question about the multiverse or world ensemble hypothesis? All right, now I think it's worth pausing for a moment here to reflect on what is going on. The current debate over the fine tuning of the universe has now become a debate over the many worlds hypothesis. And I'm not exaggerating. This hypothesis is at the heart of the discussion today. In order to explain fine tuning, we are being asked to believe not only that there are other unobservable universes, but that there are an infinite number of these universes and moreover, that that they randomly vary in their constants and quantities. All of this is needed in order to guarantee that life permitting universes like ours will appear by chance in the ensemble. Now this is really extraordinary when you think about it. It's a sort of backhanded complement, if you will, to the design hypothesis. Because otherwise sober scientists would not be flocking to adopt so speculative and extravagant a view as the many worlds hypothesis unless they felt absolutely compelled to do so. The fact that many theorists are turning to the many worlds hypothesis to rescue the alternative of chance is perhaps the best evidence that the appeal to chance is is in trouble. The odds against the existence of a life permitting universe are just too great to be faced unless you embrace the hypothesis of a world ensemble. In fact, when I was doing the seminar on fine tuning last summer at St. Thomas University, one of the other professors in the seminar was Neil Manson, professor of philosophy.

[B]

And.

[A]

And Neil had done an extraordinary sociological survey of contemporary cosmologists about issues like fine tuning. And what Manson asked the cosmologists was, do you think that other theorists who adopt the multiverse hypothesis do so in order to avoid the design hypothesis? Now, he was very clever to ask it that way. He didn't say, do you adopt it for that reason? That would make them have to confess, yes, I, as a scientist am really trying to avoid design and that's why I believe in the world ensemble. No, he said, do you think your colleagues who believe in the multiverse are motivated by a desire to get away from design? And again, he didn't mention God, he mentioned design. And what he found was that over 50% of the respondents said that they did believe that in fact, a large part of the motivation among contemporary cosmologists for belief in the world ensemble or multiverse hypothesis was because they wanted to avoid the idea of a cosmic designer. So the next time somebody says to you, oh, well, it could have happened by chance, or, well, the improbable happens, or it was just dumb luck, then ask them, well, if that's the case, why do the detractors of design feel compelled to embrace an extravagance like the world ensemble hypothesis in order to avoid design? The fact that they would resort to such a metaphysical hypothesis, I think, is, as I say, the best evidence that the chance hypothesis is in deep trouble. So how might one respond to the many worlds hypothesis? Now, at one level, one might think, well, this is a metaphysical view that would not be susceptible to scientific evidence or adjudication. You just have a standoff here between divine design and multiverse or world ensemble hypothesis. But in fact, I think that there are some real problems with the world ensemble hypothesis that make it less preferable to the design of hypothesis. One way to respond to the many worlds hypothesis would be to show that the multiverse itself also requires fine tuning. In order to be scientifically credible, some plausible mechanism has to be suggested for generating the many worlds in the ensemble. But if the many worlds hypothesis is to be successful and in attributing fine tuning to chance alone, then the mechanism that generates the many worlds had better not be fine tuned itself. Otherwise you just kick the problem upstairs and the whole debate arises all over again on the level of the multiverse. But the proposed mechanisms for generating a world ensemble are so vague that it's far from evident that the physics governing the multiverse will be free of any fine tuning. For example, if M theory or superstring theory, which we briefly talked about the other day, is the physics generating the world ensemble, then it remains unexplained, as we've seen, why exactly 11 dimensions exist. And the mechanism that actualizes all of the possibilities in the so called cosmic landscape may also involve fine tuning. So just postulating a world ensemble isn't sufficient to get rid of the alternative of design. You'd have to provide a scientifically credible model of the multiverse that doesn't involve fine tuning itself. And nobody's been able to do that. A second response to the many worlds hypothesis is that many theorists are skeptical that these many worlds even exist. Why should we think that a world ensemble of other invisible universes actually exist exists? There really isn't any evidence that the sort of world ensemble required by the multiverse hypothesis is actually real. Even if there were other universes, there's no reason to think that they're randomly ordered or that they are infinite in number. And so, as George Ellis, who is perhaps the most famous cosmologists in the world today, has emphasized, the many worlds hypothesis, as it stands today, is not a hypothesis that is capable of scientific proof. Now, by contrast with this, we have good independent reasons for believing in a designer of the universe, namely Leibniz's cosmological argument and Al Ghazali's Kalam cosmological argument. So the design hypothesis enjoys independent reasons for thinking that such a being exists, whereas there is no independent reason for thinking that the world ensemble exists. It's simply postulated to explain the fine tuning without any independent evidence for thinking that there is such a thing. Moreover, thirdly, the many worlds hypothesis faces what may be a truly devastating objection. Do you remember when we talked about the thermodynamic properties of the universe, we discussed Boltzmann's many worlds hypothesis. You remember that the Austrian physicist Ludwig Boltzmann tried to explain away the current disequilibrium of the universe by a kind of many worlds hypothesis. He said that the universe as a whole really is in a state of equilibrium, but there are just little pockets of disequilibrium throughout the universe. And these are different worlds, he called them worlds. And we are one of these little pockets. We are one of these worlds. And you'll recall what sank Boltzmann's hypothesis was that if our world is just a random member of a world ensemble like this, then it's vastly more probable that we should be observing a much smaller region of order than the vast universe that we do. In order for us to exist, all you would need would be a small fluctuation from equilibrium, say enough, to produce our solar system, and not an entire universe which exists in such a state. And it turns out that a parallel problem faces the many worlds hypothesis as an explanation of cosmic fine tuning. The Oxford University physicist Roger Penrose has pressed this objection, that with great force. Penrose points out that the odds of our universe's initial low entropy condition existing by chance alone, or somewhere on the order of one chance out of 10 to the power of 10 to the power of 123, a truly incomprehensible number. By contrast, the odds of our solar systems forming by just a random collision of particles, Penrose calculates to be about one chance out of 10 to the power of 10 to the power of 60, a number which is so tiny in comparison to 1 to the power of 10 to the Power of 123 that Penrose calls this number utter chicken feed by comparison with 10 to the 10 to the 123rd. Now, what that implies is that it is far more likely, incomprehensibly more likely, that we should be observing an orderly universe no larger than our solar system, since a world like that would be unfathomably more probable than a finely tuned universe like ours. In fact, we wind up with the same sort of illusionism that attended Boltzmann's hypothesis. A small world with the illusion a wider universe is more probable than a real fine tuned universe. It would be more probable that we really do inhabit a little tiny universe and that the stars and the planets we observe are just illusions, pictures, as it were, on the heavens, and not real stellar and extra nebular bodies that exist out there in the universe. And carried to its logical extreme, this has led to what has been called among physicists the invasion of the Boltzmann brains. Reminiscent of a 1950s grade B horror movie, the invasion of the Boltzmann brains for the most probable universe that could exist would consist of a single brain brain which fluctuates into existence out of the quantum vacuum by a random quantum process with illusory perceptions of an external world around it. And so, if you accept the many worlds hypothesis, you would be obligated to believe that you are the only thing that exists and that this class, the people around you, your family, your own body, all of these things are simply illusions that you project. In fact, you are really a Boltzmann brain. Now, no sane person believes that he is a Boltzmann brain on atheism. Therefore, it's highly improbable that there exists a randomly ordered world of ensemble. In fact, here's the irony. The best hope for the multiverse or world ensemble hypothesis is theism. The best hope for this is to say that God has created the world ensemble and he has ordered its worlds so that they are not randomly ordered. God could give a preference to observable worlds which are cosmically fine tuned. And so to be rationally acceptable, the many worlds hypothesis really needs God. Because if there is no God on naturalism alone, it would be highly, highly improbable that we should be observing this fine tuned universe. It would be far more likely to believe that you're a Boltzmann brain. Any comment or question on those objections to the attempt to save the chance hypothesis by appeal to a world ensemble? Yes, Bruce, again.

[B]

Again I'm getting airtime, but I would think another physical objection would be if we have an expanding universe and we have CBR at a certain temperature, come from all directions, that you would have an interference with other universes, especially if they were expanding and they were doing so similar things.

[A]

Well, here, if I can interrupt in the interest of time, the idea is that our universe is like a bubble in a wider mother universe that is also expanding. And so the bubbles don't run into each other because the mother universe is growing so fast that the bubbles don't collide with each other. They become separated, they can't keep up. And so again, you see a little bit of the way in which the hypothesis needs to be finessed in order to avoid these problems. Some other comment or question? Yes, Cody?

[D]

Yeah, I was just wondering about, you know, when they postulate the multiverse, they say like an infinite amount of universes. Well, how do they know it's an infinite amount? Why can't. I mean, setting aside the issues I know you've got with actual infinity, setting that aside, how they know it's not. What if there's just 100 universes out there? Or maybe there's just 50 or 10 universes.

[A]

Yeah, or even a trillion. That's not going to be enough given the numbers we're dealing with. I think you're absolutely right. And this is particularly poignant question. If the universe generating mechanism that makes these bubbles has only been chugging away for a finite amount of time, and we've already seen that the best evidence of contemporary cosmology is that the universe began to exist about 13.7 billion years ago or so, so how do we know, as you say, that there's been enough time for such a world ensemble to be created. It's completely ad hoc, that is to say, contrived. Any other question or comment? All right. With the failure of the many worlds hypothesis, the last ring of defense for the alternative of chance collapses. It seems that neither physical necessity nor chance provides a good explanation of the fine tuning of the universe. So what about design? Is design any better an explanation of the fine tuning of the universe or is it equally implausible? Well, that will be the question that we take up next week. Let's end with a benediction. And now may the God of peace fill your hearts with peace in believing, casting all your anxieties upon him and trusting in his sovereign care, letting each day's trouble be sufficient for that day. Amen. The copyright for the content of the of this recording is held by Dr. William Lane Craig. For more go to reasonablefaith.org.