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Does Fine Tuning Require a Fine Tuner?

KEVIN HARRIS: Hey! So glad you’re here on Reasonable Faith with Dr. William Lane Craig. I’m Kevin Harris. Hope and pray you are safe and healthy. Dr. Craig and Jan are doing well. Dr. Craig has been doing a lot of online interviews lately. Skyping and Zooming, all that stuff. So be sure and check out our YouTube channel, and in particular our friend Cameron Bertuzzi of Capturing Christianity has several interviews with Dr. Craig including a recent interaction with Dr. Graham Oppy on God and math[1]. You definitely want to check that out. We're going to be talking about that here on a Reasonable Faith podcast as well.

Let's get into today's podcast. We're talking about the fine-tuning argument for God. And keep in mind the three alternatives when it comes to fine-tuning that you hear Dr. Craig talk about. The fine-tuning of the universe is either due to chance, physical necessity, or design. Today's podcast is a chance to, well, fine-tune your knowledge of the fine-tuning argument.

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“Fine-Tuning Does Not Imply a Fine Tuner”[2] Dr. Craig, this is an article that I think kind of took you by surprise. It is by Hans Halvorson who is in the department of philosophy at Princeton. He says, “Some think fine-tuning is evidence for God, but in fact the opposite is true.” Why did this take you by surprise?

DR. CRAIG: The reason I'm surprised is that Hans Halvorson, whom I know personally, is a brilliant philosopher of quantum physics, and therefore I'm surprised that he would find these arguments persuasive. It almost seems as though he's not familiar with the best statements of the argument from fine-tuning for design such as are offered by Robin Collins and Luke Barnes. So I’m puzzled that he would think that these objections he raises are insuperable.

KEVIN HARRIS: About the middle of the page he defines the fine-tuning argument. He says,

The fine-tuning argument rests on an interesting discovery of physical cosmology that the odds were strongly stacked against life.

This new fine-tuning design argument claims the imprimatur of physics, and is presented in quantitatively precise terms: among the set of all possible universes, the percentage that could sustain life is so small that the human mind cannot imagine it. By all rights, our universe shouldn’t have existed. What wonder that our universe has given birth to life, especially intelligent life. It seems the only explanation for this wildly improbable outcome is the supposition that there is a Designer.

But could it really be that physics points to God’s existence?

DR. CRAIG: This is a popular statement of the argument. It is imprecise. It lacks rigor. But I'm not going to quibble with it. We'll get into the more precise formulation of the argument as we proceed. So let's just accept this to get the conversation started.


Let me put my cards on the table. I believe that our universe is the creation of an omnipotent being. And I agree with John Glenn who said, “Looking at the Earth from this vantage point, looking at this kind of creation and to not believe in God, to me, is impossible.” But the attempt to parlay this sense of wonder into a scientific proof is fraught with danger. And the fine-tuning argument is no exception.

DR. CRAIG: This is interesting. He seems to think that belief in God is a properly basic belief that is grounded in this sense of wonder and awe at the universe, but that when you attempt to express this as an argument then he is going to find that problematic. I take it that for Halvorson, belief in God is a properly basic belief (indeed, he says it's impossible not to believe, for him) grounded in one's experience of the universe, but one can't formulate an argument for God's existence that would be a sound argument.

KEVIN HARRIS: He continues,

There’s a deep problem lurking in the background of the fine-tuning argument, which rests on two factual claims. One is that a life-conducive universe exists.

DR. CRAIG: Now here we have to begin to quibble. The fine-tuning argument as usually stated does not assert that a life-conducive universe exists. “Conducive” means “apt to produce something” – that life would be more probable than not given the way the universe is. And that's no part of the fine-tuning argument. Rather, the fine-tuning argument as usually stated by people like John Leslie and others is that a life-permitting universe exists. The fundamental constants and quantities of nature are such as to permit the origin and evolution of embodied, conscious agents in the world. So it isn't a part of the traditional fine-tuning arguments that a life-conducive universe exists.


And the second is that this kind of universe is improbable.

DR. CRAIG: Now, again, this is a problematic statement if we're going to be doing a rigorous argument here. With probability arguments, they are always relative to background information. Improbable with respect to what? And here the proponents of a fine-tuning argument will say that the fine-tuning of the universe is improbable relative to naturalism or relative to a single atheistic universe, but that relative to theism the fine-tuning is not improbable. When you look at the ratio between fine-tuning relative to naturalism compared to fine-tuning relative to theism, the fine-tuning is vastly, vastly more improbable on naturalism than it is on theism. So there is no sort of absolute claim that fine-tuning is improbable. It’s improbable with respect to certain background information. Indeed, the way Robin Collins formulates the argument, he doesn't even calculate the probability of fine-tuning. Rather, he argues that embodied, conscious agents are vastly more improbable with respect to a single naturalistic atheistic universe than they are relative to theism. Given theism, it is more probable that embodied, conscious agents would exist than it is on an atheistic single universe hypothesis.

KEVIN HARRIS: He says that it's this second fact that is responsible for the resurrection of the design argument. Do you think that’s the case? Because it has come roaring back.

DR. CRAIG: Oh, yes. I do think that it is the improbability of the fine-tuning on naturalism that has helped to promote this argument and to make it a common topic among physicists today in journals and at scientific meetings in an attempt to try to find the best explanation for why our universe exhibits this uncanny fine-tuning for life.

KEVIN HARRIS: What he says is that,

fine-tuning advocates are so focused on using it [the second principle] as a premise that they’ve failed to see that it needs explanation. That is, why is it the case that it’s unlikely for an arbitrary universe to be conducive to life?

DR. CRAIG: Here is again one of these places where I'm baffled. I think, “Have you not familiarized yourself with the literature on fine-tuning?” Of course the advocates of fine-tuning are seeking an explanation of why it is so improbable. The idea here is that the assumable range of values for these constants and quantities (that is to say, the values they could have) consistent with the laws of nature is so vast compared to the range of life-permitting values that they are that it makes it enormously improbable that a life-permitting universe should exist. A dart randomly thrown at the range of values would in all probability strike a life-prohibiting universe. The range of life-permitting values is practically infinitesimal compared to the range of assumable values. So a randomly thrown dart would take one of these values that is a life-prohibiting universe. It is in that sense that it is enormously improbable relative to naturalism that a fine-tuned or life-permitting universe should exist.

KEVIN HARRIS: He continues,

. . . why is it the case that it’s unlikely for an arbitrary universe to be conducive to life?

It’s not plausible to write it off as a brute necessity, because it’s not obvious that this had to be the case, nor could it have been discovered by pure reason alone.

DR. CRAIG: All right! So what alternative is he excluding there as an explanation for the fine-tuning? Among the three alternatives that we typically discuss in dealing with the fine-tuning argument, this is the alternative of physical necessity. And he is saying he agrees: it's not plausible to explain the fine-tuning by physical necessity. So that means if he's going to deny design, he's going to have to revert to the chance hypothesis.

KEVIN HARRIS: Here he says,

But even if we do find the much-needed explanation, it will be disastrous for the fine-tuning argument, because it would disconfirm God’s existence. After all, a benevolent God would want to create the physical laws so that life-conducive universes would be overwhelmingly likely.

DR. CRAIG: Now this is a shocking claim on Halvorson’s part! In fact, I think it's crazy to assert this. Why does he think that if God exists that God would create a universe in which fine-tuning is probable on naturalism? I can't think of any reason God would do such a thing. Why not create a universe in which fine-tuning is probable on theism but improbable on naturalism? Maybe God wanted to leave evidence of his existence, and so by creating a universe that in all probability would never have evolved life if God did not exist, God has left remarkable evidence of his existence in nature. So I find Halvorson's claim here to be just bizarre that he would think to know what God would do about this. This is what Kevin Sharpe in my dialogue with him at Ohio State University a few years ago called divine psychology, and Halvorson is indulging here a little bit of divine psychology in saying that if God existed he would create a universe in which fine-tuning would be highly probable on naturalism, which I think is nuts.


Similarly, the fine-tuning argument rests on an interesting discovery of physical cosmology that the odds were strongly stacked against life. But if God exists, then the odds didn’t have to be stacked this way. These bad odds could themselves be taken as evidence against the existence of God.

DR. CRAIG: He's right that God is at liberty to create any sort of universe that he wants – a finely tuned universe or a universe that is not finely tuned. But the fact that the odds would be stacked against life given naturalism is not in any way a disconfirmation of God's existence. On the contrary, as I explained, it would actually be evidence of God's existence that a universe exists which is so enormously improbable given naturalism but not improbable given theism since, as Halvorson says, God is at liberty to create any sort of universe that he wants.


I myself don’t think that the extreme improbability of the existence of life disproves the existence of God.

DR. CRAIG: OK! Now, here he's entering a caveat. He's withdrawing what he asserted before. He said that this is disconfirmation of God's existence that the fine-tuning is so improbable on naturalism. Now let's see why he is ready to withdraw this claim.


But that’s because I don’t think we understand God well enough to make firm predictions one way or the other about what kind of universe God would create.

DR. CRAIG: This is Kevin Sharpe’s point about divine psychology.

KEVIN HARRIS: What God would do.

DR. CRAIG: Yeah. How do we know what kind of universe God would create if he exists? But that actually serves to undercut Halvorson's argument, I think, because while you can say that embodied, conscious agents are highly improbable on naturalism, you can't say they're improbable on theism precisely because you can't do divine psychology. There isn't any way that you can assert that this is highly improbable.

KEVIN HARRIS: He wraps it up by saying,

One could go too far with this sort of skepticism. Surely the so-called fine-tuning evidence is proof of something. But the fact that our current cosmological theory can’t explain it tells us that we have more work to do. When our best science predicts a lifeless universe, and this fails to obtain, what should we do? We could say, “a miracle has occurred!” But that would be intellectually lazy. We need a theory that will make accurate predictions and integrate with other successful physical theories. The fine-tuning argument falls short because it assumes that our current cosmological theory is correct, as long as we invoke a non-scientific principle, God. I advocate a more radical and scientific reading of the fine-tuning data. It’s not a brute fact or a true premise in a theological argument. Rather it’s evidence that we need a new and revolutionary cosmological theory.

DR. CRAIG: Wow! OK. So here's Halvorson’s alternative to design. It is that we need a new and revolutionary cosmological theory. He's advocating for some sort of fantasy physics that we don't have that would apparently render the fine-tuning physically necessary, that would make it not due to chance but according to physical necessity. And this is a fantasy. There is no such physics. So this is a profoundly, I think, anti-scientific alternative. It is rooted in a kind of methodological naturalism that says there has to be a scientific explanation for fine-tuning even if that requires a thoroughgoing revision of contemporary astrophysics and cosmology. I think that theism is certainly a viable alternative to that. Notice that theism is not proposing some sort of alternative cosmological theory. As he recognizes, theism assumes that the current cosmological theory is correct. And, as to the best explanation of the fine-tuning, you could regard that as I'm inclined to do as a philosophical question, not a scientific question. I'm not proposing a new scientific theory to replace the current cosmological model. I, as a philosopher, am asking a metaphysical question that scientists are free to simply say, We don't have an explanation for this. We don't know what explains the fine-tuning. This is not a scientific question, they might say. Or, if they come to a scientific dead end, they might just throw up their hands. But to offer some sort of a fantasy physics as an alternative to theism, I think, is desperate.

KEVIN HARRIS: I wonder if he is afraid of God-of-the-gaps in this whole thing?

DR. CRAIG: Yes, that seems evident the way he characterizes that we could just say a miracle occurred, when in fact the proponents of the fine-tuning argument (like Robin Collins and others) are offering an argument based upon confirmation theory, probability calculus, and saying that the fine-tuning of the universe or embodied, conscious agents are much more probable on theism than they are on atheism. Therefore, these lend confirmation to the hypothesis of theism over atheism.[3]


[1]                [1] (accessed May 17, 2020).

[2]                [2] (accessed May 17, 2020).

[3]                [3]Total Running Time: 20:19 (Copyright © 2020 William Lane Craig)