Recently, Sean Carroll (cosmologist and atheist, whom I have met a couple times at physics events) and St. William Lane Craig (philosopher and Christian apologist) had a debate about this topic:

“God and Cosmology: The Existence of God in Light of Contemporary Cosmology.”

Transcript,  Video,  Carroll’s post-debate reflections, Craig’s: One Two Three

(Warning: when the debate transcript says something like 10500, it really means \(10^{500}\).  Apparently whoever (or whatever) transcribed it doesn’t understand scientific notation.)

Several readers have asked me to comment on this debate, and I plan to write more than one post doing so.

Let me just say first that I am not particularly interested in the question of who “won” this debate (between two people whom I both respect).  The existence of God does not, of course, depend on any particular person’s ability to effectively argue for (or against) him.  I’d rather just make some opportunistic comments based on what the participants said.  What limited comments I have about the debate as a debate I will try to confine to this post.

William Lane Craig is a skilled debater who has done his best to keep abreast of Modern Cosmology.  This is commendable, but it was inevitable that his depth of knowledge in Cosmology was not as great as Carroll, who works on this subject professionally.  And often it showed.  That is why Craig had to rely mainly on a lot of quotes from famous physicists such as Alex Vilenkin—and sometimes this backfired, as in the case of Alan Guth, who apparently believes that the universe is eternal.

Since the topic was limited to Cosmology, Craig was unable to bring in any other types of evidence for the existence of God, besides those related to the Cosmological or Fine-Tuning Arguments.  In other debates, Craig has focused more on the evidence for miracles (such as the Resurrection of Jesus), which personally for me is much stronger evidence for the existence of God than anything coming from Cosmology.  For me, if Modern Cosmology is sufficient to get people to even wonder, “Is there maybe somebody who did that?” that’s enough to start with—so long as it makes them curious enough to start exploring other lines of evidence, based on History or personal experience.

In other words, it’s not necessary for Cosmology by itself to get people to a belief in God.   What matters is the cumulative case from Cosmology plus everything else.  If there are puzzling things such as fine-tuning which might be explained by God, and might have a different explanation (e.g. the multiverse), to me the most natural response seems to be to keep an open mind about all possible explanations.  But that would imply, that at least the existence of God is not absurdly unlikely (so far as Cosmology is concerned).  And if a person gets that far, then when they examine historical evidence or religious experiences, at least they won’t do so with a giant presupposition in favor of Naturalism that requires them to explain away practically anything.

Assuming they are rationally consistent, that is.  Most people, if you try to argue for some proposition X that they don’t want to believe in, will ask only whether the argument is so compelling as to force them to believe in it.  If not—if they can think of any possible way to defeat or evade the argument—they will act as though the argument has no force at all.  They are like the fearsome Barghest of legend, a monstrous black dog which can only be killed with a single blow.  If you do not strike hard enough to kill, then all of the damage is transferred from it to you.  (At least, that’s how it works in Pendragon, the Arthurian Roleplaying System.)  With such people, if they can find any clever loophole in your argument—even if it involves totally speculative new physics—the next day they will say that the argument was refuted and provides no evidence for X at all.  This makes it impossible to make a cumulative case argument.

Anyways, I thought Craig did a pretty good job of sticking to the restricted topic of Cosmology.  Carroll somewhat less so, when he said:

If theism were really true there’s no reason for God to be hard to find. He should be perfectly obvious whereas in naturalism you might expect people to believe in God but the evidence to be thin on the ground. Under theism you’d expect that religious beliefs should be universal. There’s no reason for God to give special messages to this or that primitive tribe thousands of years ago. Why not give it to anyone? Whereas under naturalism you’d expect different religious beliefs inconsistent with each other to grow up under different local conditions. Under theism you’d expect religious doctrines to last a long time in a stable way. Under naturalism you’d expect them to adapt to social conditions. Under theism you’d expect the moral teachings of religion to be transcendent, progressive, sexism is wrong, slavery is wrong. Under naturalism you’d expect they reflect, once again, local mores, sometimes good rules, sometimes not so good. You’d expect the sacred texts, under theism, to give us interesting information. Tell us about the germ theory of disease. Tell us to wash our hands before we have dinner. Under naturalism you’d expect the sacred texts to be a mishmash—some really good parts, some poetic parts, and some boring parts and mythological parts.

[As an aside, there’s something a bit funny here.  Carroll thinks that God should have provided us with some scientific information in the Bible.  The most useful scientific fact he can think of is the importance of good hygiene.  And it is a fact that the most famously boring book of the Bible, the book of Leviticus, is chalk full of hygiene rules about cleanliness (embedded among other religious rituals).  Fairly decent rules too, given the 2nd millennium BC context.  No germ theory of disease, I admit.  But highly practical nonetheless.  Now, I’m not a religious fundamentalist who thinks that the Bible is a Science textbook.  Nor am I an antireligious fundamentalist who thinks it ought to have been a Science textbook.  But I do think it is ironic that the particular thing Carroll demands is, in some sense, present in the least-loved book of the Bible!  Carroll continues:]

Under theism you’d expect biological forms to be designed, under naturalism they would derive from the twists and turns of evolutionary history. Under theism, minds should be independent of bodies.  Under naturalism, your personality should change if you’re injured, tired, or you haven’t had your cup of coffee yet.

[Huh?  Theism is the belief that God exists.  It does not commit one to any particular view about the soul’s relationship to the body.  The fact that our personalities are encoded in our brains is logically independent to the question of whether God exists.  Particular religious traditions might have particular views about the soul, but that’s not what we’re talking about here.]

Under theism, you’d expect that maybe you can explain the problem of evil – God wants us to have free will. But there shouldn’t be random suffering in the universe. Life should be essentially just. At the end of the day with theism you basically expect the universe to be perfect. Under naturalism, it should be kind of a mess—this is very strong empirical evidence.

This, however, strayed from the parameters of the debate topic.  Whatever the merits of the Argument from Evil, it cannot be said that Evil is a discovery of Science.   It has nothing to do with Cosmology.  It is not a discovery of contemporary physics that there is random suffering, and that the universe isn’t fair.  (What would a scientific theory of “Justice” even look like?)  Granted, the Argument from Evil is relevant to the cumulative case concerning God’s existence (some of my own thoughts about that are here.)  But then Craig would also be entitled to throw in historical data about Jesus and anything else that might be relevant to the inquiry.

Naturally Craig called him on it:

He is very concerned to show that God’s existence is improbable relative to certain non-cosmological data. For example, the problem of evil, our insignificant size, and so forth. The very fact that these are non-cosmological data shows that they are not relevant in tonight’s debate. I have addressed things like the problem of evil extensively, for example, in Philosophical Foundations for a Christian Worldview.  So the debate tonight is not over the probability of theism versus naturalism. That would require us to assess all sorts of non-cosmological data. Rather, the question is: is God’s existence more probable given the data of contemporary cosmology than it would have been without it? And I think it certainly is.

Craig, being a skilled debater, makes sure to frame the debate question to be one which is comparatively easy to show.  According to Craig’s framing, he only needs to show that Theism is more plausible given e.g. our current understanding of the Big Bang Model, compared to if we didn’t know these facts.  This is a fairly modest ambition.  It certainly seems more likely now that the universe has a beginning than it would have seemed to a materialist living 500 years ago.  So if the beginning of the universe is a relevant datum for the existence of God, then cosmology provides some positive evidence.   (On the other hand, if it isn’t relevant, why are we even discussing whether there was a beginning?)

At times, Carroll even seems to assume that if Craig doesn’t believe in Theism for scientific reasons, his views can’t be based on evidence at all:

There are very few people in the modern world who become religious, to come to believe in God, because it provides the best cosmology or because it provides the best physics or biology, or psychology, or anything like that. And that includes Dr. Craig. There’s a famous quote by him that says, “The real reason, the primary reason, for believing in Christianity isn’t cosmological arguments.”

[I was unable to track this quote down, but having some knowledge of Craig’s views in other contexts, I highly doubt that Craig was referring to some inarticulate leap of faith not grounded in any good evidence at all.  I imagine—especially since he referred to Christianity—that he was thinking about some type of historical evidence that has to do with, say, Jesus or something.  Maybe something related to the fact that he did lots of miracles, and rose from the dead, and was seen by many eyewitnesses, who themselves did several miracles, leaving a band of committed followers to this day, who sometimes do miracles in his name, including naturalistically inexplicable healings with solid medical documentation—have I made my point yet?]

I’m not mentioning this as a criticism; it is simply an observation of fact. There are other reasons to be a theist other than cosmology, and I think that is true. I think that makes sense. Most people who become religious do so for other reasons—because it gives them a sense of community, a sense of connection with the transcendent, it provides meaning or fellowship in their lives.

These subjective warm fuzzy feelings are nice and all, but it is scientism to think that they are the only thing left after we remove stuff like Cosmology.  For example, History is also an evidence-driven field, and it has plenty of data supporting things like miracles.  Carroll made a joke about taking into account new evidence if the roof were to fall on his head, but perhaps if Carroll does some historical investigation, there might be more subtle ways for God to make a point.

The problem is that the basis of religion in the modern Western world is theism, belief in the existence of God. I’ve tried to make the case that science undermines theism pretty devastatingly. Five hundred years ago it would have made perfect sense to be a theist. I would have been a theist five hundred years ago. By two hundred years ago science had progressed to the point where it was no longer the best theory. By a hundred years ago after Darwin it was a rout. And by these days with modern cosmology there’s no longer any reason to take that as your fundamental worldview.

I always find it interesting, that when you poke a person who makes grand claims about the philosophical implications of Science, sooner or later they end up telling one of these historical just-so stories about how things used to be completely different before Science came along.

You know the drill.  Once upon a time, people used to use God to explain everything, and then one or two things got explained by Science, and then some more things got explained by Science, and now there are only two or three gaps in our knowledge, which stubborn religious people cling to in order to justify Theism, but we all know (by linear interpolation, I guess) that Science will eventually explain these things too, which is just as good as if it already had done so.  (This is closely related to the infamous “God-of-the-Gaps”™ strawman, about which I will have more to say later.)

In order to tell this story properly, Carroll needs to insist that he would have been a pious religious person 500 years ago.  But I’m not at all sure this is true.  He didn’t really present any arguments for Theism based on the Science of 500 years ago, let alone one which is refuted by our present day understanding.  All he did was say why he doesn’t believe in Craig’s arguments (which, whether you believe them or not, are based on Modern Science, and couldn’t even have been made 100 years ago, let alone 500).   All that stuff about random suffering, and multiple religions, and weird stuff in the Bible, and that the universe is really big while Earth is really small, and that tiredness and drugs and physiological secretions influence the mind, was just as evident to smart people 500 years ago as it is now.

No matter how much lecturing you hear about how Science works because we can always correct our theories with new data, they seldom bother to check these supposedly historical narratives with any actual data.  When you do, you usually find the story is far more complicated.

In the paragraph quoted above, the only actual Scientific revolution mentioned is that due to Darwin.  The rest is left suspiciously vague (for example, I’m not sure from the description what exactly is supposed to have happened 200 years ago, that made Theism “no longer the best theory”).

In fact, for the most part it’s pretty unclear what the implications of scientific theories are for or against Theism.  Take for example Maxwell’s equations.  One could try to argue that: 1) lots of stuff is described by equations, 2) Maxwell’s equations mean that one more thing is described by equations, 3) therefore probably everything is described by equations, 4) God is not an equation, therefore 5) God does not exist, but this seems like a rather weak argument from induction, not something that “undermines theism pretty devastatingly”.  It’s not like anyone in the 1500’s was saying that magnetism couldn’t be understood except as a special miracle of God, and then St. Maxwell showed they were all wrong.

There’s a reason, therefore, why people fixate on Darwin.  Darwin’s theory of Evolution really did remove one possible argument for the existence of God: namely that an act of special creation was necessary to explain the existence of each individual species, and its close adaptation to its environment.

Of course, the removal of a particular argument for God’s existence isn’t the same as disproving Theism.   In particular, this argument for the existence of God was not by any means the historically most important one.  In fact, you only really see people shortly before Darwin (like St. William Paley) making this argument.   In medieval times, people used to think that life-forms like flies would spontaneously generate in rotting meat.  Obviously, they wouldn’t have thought much of Paley’s view that each species needed to be created individually by God.  It was only with the increase of scientific understanding that this “gap” in our understanding was noticed.  Thus, to say that filling this gap refutes the ideas of the medievals (who didn’t even know there was a gap here to be filled) is absurd.

What history actually shows, is not a monotonic replacement of Theology by Science, but a complicated back-and-forth process where new Science produces some new arguments for Theism (Paley, fine-tuning…), discredits others (Paley, the need for a Prime Mover rotating the outer heavenly sphere…), and so on.  But that’s too complicated to reduce to a tidy, one-sided historical meta-narrative, so lots of people just make up a story about Science and Religion being enemies, and stuff everything into that mold.

All of this was just picking around the edges.  In the next post, I will talk more about the so-called God-of-the-Gaps™-fallacy, which both Carroll and Craig pay their obligatory disrespects to.  Then I’ll try to get to the actual substantive questions about whether the universe had a beginning, according to Modern Science.  And whether that has any theological implications.  And fine-tuning.  And about Carroll’s arguments that Theism is ill-defined and false.   Things that relate to the actual substance of the Carroll-Craig debate.  That sounds like a plan.

Today I went to a talk by Lawrence Krauss entitled “A Universe from Nothing”, which had the following abstract:

The question, “Why is there something rather than nothing?” has been asked for millenia by people who speculate on the need for a creator of our Universe.  Today, exciting scientific advances provide new insight into this cosmological mystery: Not only can something arise from nothing, something will always arise from nothing.  Lawrence Krauss will present a mind-bending trip back to the beginning of the beginning and the end of the end, reviewing the remarkable developments in cosmology and particle physics over the past 20 years that have revolutionized our picture of the origin of the universe, and of its future, and which have literally revolutionized our understanding of both nothing, and something.  In the process, it has become clear that not only can our universe naturally arise from nothing, without supernatural shenanigans, but that it probably did.

In the first 45 minutes, he provided an animated and reasonably clear explanation of concordance cosmology, the current version of the Big Bang model, dating from the discovery in 1998 that the expansion of the universe is accelerating (rather than decelerating as one would expect from the attractive gravity of ordinary matter).  This is exciting but now well-established work, which I’ve heard about a hundred times before, but was probably new to many of the people in the audience.  It was peppered with occasional off-hand sneers at Republicans, Theology, and Young Earth Creationism, but for the most part it was a pretty valiant stab at popularizing an important set of 20th century discoveries.

The real reason I was there, of course, was to listen to his claims in the last 15 minutes that modern cosmology somehow points to the nonexistence of a Creator.  His claim was that there is evidence that the universe came from “Nothing” according to physical processes, and this apparently is supposed to undermine the religious view that God created the world supernaturally.  There were so many things wrong with this part of his talk, both a physics and a philosophical perspective, that I’m not entirely sure where to begin.  But let’s try anyway.

His Slam on Theology.  Krauss said that Theology wasn’t based on empirical evidence, so therefore he didn’t believe it.  That was it.  He didn’t seem to take any particular theological ideas seriously enough to even try to define them, let alone refute them.  There was no indication that Religion had any other origin besides a bunch of clueless dudes sitting around asking “Why is there Something rather than Nothing?”  (In the case of Christianity, I thought it had more to do with a guy claiming to be God, doing miracles, and dozens of people saying that they saw him alive after he was killed.  But what do I know?)

But let’s get back to cosmology, since that was the subject of his talk.  It used to be that Christians believed that the world was created a finite time ago, out of Nothing.  Although some of them, like St. Thomas Aquinas, said that God could have created a universe with an infinitely long past.  Atheists had (and have) a diversity of opinions, but most of them thought that things would make more sense if the universe were around forever, since then maybe you wouldn’t have to explain where it came from.  Then Big Bang cosmology came along, and it now seems—provisionally speaking—like the Universe really did have a beginning.  Now some atheists think they can refute the Christian view that God created the Universe from Nothing by arguing that the world did emerge from Nothing.  The role-reversal here is a little strange.

What Christians mean by creation ex nihilo is that God created the Universe, but that he didn’t make it out of any pre-existing stuff that was lying around.  Thus, while the universe didn’t come “out of” anything, it still comes from God.

What Krauss seems to mean is something quite different, namely that there’s some specific entity we can talk about called “Nothing”, which has suitable properties for generating our universe.

But the universe can only come from nothing if you define a certain kind of something as being “Nothing”.  Duh, because any explanation by its very nature must explain one thing in terms of some other thing!  This other thing must be taken for granted for purposes of the explanation.  Now, Krauss actually referred to 3 different ideas which he called “Nothing #1, #2, and #3”:

Nothing #1: an “empty” spacetime a.k.a. the vacuum.  In ordinary non-speculative quantum field theory (QFT), the “vacuum state” (the configuration of fields with the lowest energy) is actually filled with so-called virtual particles which can affect physics in various ways.  At least, that’s what the popularized physics books say; if one actually studies quantum field theory rigorously, people tend to use somewhat different language since the notion of “virtual particle” can be difficult to define.  But let’s spot him the terminology since he was talking to a popular audience.

Krauss claimed that if you start with an empty space which has no virtual particles in it, virtual particles will appear, and this is “something” coming from “nothing”.  This is bosh, since strictly speaking, there’s no such thing in QFT as a state with no virtual particles.  (If there were, it would be infinitely different from the vacuum state, and would therefore have an infinitely large energy.  That’s not nothing at all!)  If anything can colloquially be called “Nothing” in QFT, it is the vacuum state.  But this state already has all those virtual particles in it.  And as time passes, this vacuum evolves to….wait for it….itself!  That’s right, if you agree to call the vacuum state Nothing, then Nothing comes out of it.  (He seemed to think this story might change once you take gravity into account, due to negative energies, but I didn’t really understand this suggestion so I won’t comment on it.)

The QFT vacuum isn’t nothing.  Of course, from a strict philosophical point of view, the vacuum state of QFT is not Nothing since it’s filled with all those virtual particles, and even aside from that, there’s the space and time geometry, which is not Nothing.  To fix this he started taking up a different kind of nothing:

Nothing #2: the absence of any space or time.  This actually connects to an interesting quantum gravity idea known as the “Hartle-Hawking state” or the “no-boundary boundary condition”.   (Jim Hartle is on my floor at UCSB, by the way.)  The suggestion is that the laws of physics not only tell you how the universe at one time evolves to a later time, they also tell you what the initial state of the universe is.

In some sense, one can think of this state as emerging out of Nothing #2.  However, the sense in which this is true is subtle.  There’s another sense in which the Hartle-Hawking state does not emerge from Nothing; rather it has existed for an infinite amount of time— the popular physics articles never mention this, for some reason!  This is an interesting and important idea, but I think it deserves to be in it’s own post, after I’ve explained QFT better.  The important thing to know is the following:

The crucial physics here is totally speculative!  It was entirely based on speculative ideas about quantum gravity which anyone working in the field would admit are not proven.  This is because we currently have no experimentally testable theory of quantum gravity!  (Nor do we even know how to formulate a consistent theory of quantum gravity mathematically, except perhaps in some special situations that probably don’t apply to the beginning of our universe)

I mentioned this in the Q&A afterwards.  My comment seemed to aggravate him a little, since he thought he’d been sufficiently clear about this.  But I discovered that at least one member of the audience was still unclear on which parts were speculative, and which weren’t, at the end of the lecture.  In my experience, one has to be crystal clear about this sort of thing when speaking to a popular audience, or they tend to walk away thinking that “Science” has proven things when it hasn’t.

Atheists such as Krauss scorn theology as being completely non-empirical.  They claim it is not based on evidence of any sort.  I find it extremely ironic when this sort of atheist thinks that speculative quantum gravity ideas are just the right thing to further bolster their atheism.  Suppose you think that Science is better than Religion because it is based on evidence, and suppose you also want to refute Religion by using Science.  Here’s a little hint: consistency would suggest using a branch of Science that actually has some experimental data!

The universe has zero energy.  Krauss thinks that the universe coming out of Nothing has been made more plausible by cosmology.  To understand his terminology, you have to know that (roughly speaking) a closed universe means that space at one time is finite in volume, and shaped kind of like a sphere, so that if you travel around the universe far enough you come back to where you started.  On the other hand, in a flat universe, space at one moment of time is shaped like ordinary Euclidean geometry, and is infinitely large.  Current observations indicate that the universe is flat.  As far as I could tell, Krauss’ argument can be translated into these terms:

1. The total energy of a closed universe is zero.  (It’s tricky to define energy in general relativity, but according to one commonly used definition, this is true.)
2. Conservation of energy suggests that if the universe came from Nothing, it should have zero energy.
3. If there was a period of extremely rapid expansion at the beginning of the universe (as evidence suggests there was—this is called inflation), then whether or not the universe started out closed, it should look flat today.
4. But the universe does look flat,
5. Therefore Science suggests that the universe was created out of Nothing,
6. Therefore there is no need for God.

Perhaps I’m missing some crucial steps in his argument.  But there seem to be several enormous leaps of logic in there.

The Hartle-Hawking state isn’t Nothing either.  Strictly speaking, even the Hartle-Hawking idea doesn’t strictly get the universe out of Nothing, since it says that the initial state of the universe depends on the laws of physics.  Now the laws of physics aren’t nothing.  So if, for example, you are wondering if there is any role left for the Creator, then one might say he picked the laws of nature.

Now, there’s all sorts of difficult philosophical issues involved in what’s called the Cosmological Argument for the existence of God.  But it’s hard to get into them with someone like Krauss who is so dismissive of Philosophy.  The trouble with people like that is that it isn’t possible to just find things out using Science instead of Philosophy.  That’s because you have to do Philosophy to know what is or is not implied by Science.  People who dismiss Philosophy still end up doing it; they just do it badly, without a critical examination of their premises.

Nothing #3: the string theory multiverse.  Krauss acknowledges that the laws of phyiscs themselves might seem to call  for an explanation.  Especially since the various constants of Nature seem to be “fine-tuned” to allow the existence of life (I’ll go into this in much more depth later).  On the face of it, this seems to be at least some mild evidence for the existence of God, but Krauss would never admit such a thing.

He suggests that we can explain this fine-tuning if string theory turns out to be true.  That’s because string theory has an enormous number of different possible configurations, that look like universes with different laws of physics.  Some people have suggested that if there’s a gazillion different universes (known as the “multiverse”), each with its own laws of physics, that it’s not surprising that one of those universes should support life.  Krauss admitted that there was some dispute as to whether this idea counts as “Science”, what with it being totally speculative and arguably untestable.  But what I want to know is, why the $@#& would we ever refer to an infinite number of universes, governed by the principles of string theory, as a Nothing?

I should say that this review is based entirely on Krauss’ talk.  I have not read his book, but I have read this negative review by philosopher St. Feser.

[Update 7/21/20: added two paragraphs to the text, beginning “What Christians mean…” to make the argument a little clearer.]