We’ve returned from the lovely city of New Orleans, where within a short period of time I was able to sample shrimp and grits, bread pudding soufflé, turtle soup, chicken gumbo, soft-shelled crab with crawfish étouffée, and of course beignets. Oh yes, also participated in the Greer-Heard Forum, where I debated William Lane Craig, and then continued the discussion the next day along with Alex Rosenberg, Tim Maudlin, James Sinclair, and Robin Collins. The whole event was recorded, and will be released on the internet soon — hopefully within a couple of days.
[Update: Here is the video:]
In the meantime I thought I’d provide some quick post-debate reflections. Overall I think it went pretty well, although I certainly could have done better. Then again I’m biased, both by being hard on myself in terms of the debate performance, but understandably of the opinion that my actual ideas are correct. I think I mostly reached my primary goal of explaining why many of us think theism is undermined by modern science, and in particular why there is no support to be found for it in modern cosmology. For other perspectives see Rational Skepticism or the Reasonable Faith forums.
Short version: I think it went well, although I can easily think of several ways I could have done better. On the substance, my major points were that the demand for “causes” and “explanations” is completely inappropriate for modern fundamental physics/cosmology, and that theism is not taken seriously in professional cosmological circles because it is hopelessly ill-defined (no matter what happens in the universe, you can argue that God would have wanted it that way). He defended two of his favorite arguments, the “cosmological argument” and the fine-tuning argument; no real surprises there. In terms of style, from my perspective things got a bit frustrating, because the following pattern repeated multiple times: Craig would make an argument, I would reply, and Craig would just repeat the original argument. For example, he said that Boltzmann Brains were a problem for the multiverse; I said that they were a problem for certain multiverse models but not others, which is actually good because they help us to distinguish viable from non-viable models; and his response was the multiverse was not a viable theory because of the Boltzmann Brain problem. Or, he said that if the universe began to exist there must be a transcendent cause; I said that everyday notions of causation don’t apply to the beginning of the universe and explained why they might apply approximately inside the universe but not to it; and his response was that if the universe could just pop into existence, why not bicycles? I was honestly a bit surprised at the lack of real-time interaction, since one of Craig’s supporters’ biggest complaints is that his opponents don’t ever directly respond to his points, and I tried hard to do exactly that. To be fair, I bypassed some of his arguments (see below) because I thought they were irrelevant, and wanted to focus on the important issues; he might feel differently. I’m sure that others will have their own opinions, but soon enough the videos will allow all to judge for themselves. Overall I was moderately satisfied that I made the responses I had hoped to make, clarified some points, and gave folks something to think about.
Longer version (much longer, sorry): the format was 20-minute opening talks by each speaker (Craig going first), followed by 12-minute rebuttals, and then 8-minute closing statements. Among the pre-debate advice I was given was “make it a discussion, not a debate” and “don’t let WLC speak first,” both of which I intentionally ignored. I wanted all along to play by his rules, in front of his crowd, and do the best job I could do without any excuses.
In his opening speech Craig gave two arguments: the Kalam Cosmological Argument (the universe must be caused, and the cause is God), and the teleological/fine-tuning argument (the parameters of the universe appear designed for the existence of life). To his great credit, WLC actually stuck to arguments concerning physical cosmology, where presumably my expertise would be most valuable; he didn’t hide behind primarily metaphysical arguments like the ontological argument or the denial of realized infinities. The two he used were familiar from his repertoire, and they were the two that I was primarily interested in talking about myself, so we were off. (I’ll try to reconstruct the logic rather than doing a point-by-point recap, since I’m mostly working from memory. Naturally, my memory of my own parts will be sharper than my memory of WLC’s, so I’ll happily accept factual corrections.)
The cosmological argument has two premises: (1) If the universe had a beginning, it has a transcendent cause; and (2) The universe had a beginning. He took (1) as perfectly obvious, and put his effort into establishing (2). Partly he used the celebrated (by theologians) Borde-Guth-Vilenkin theorem, which says that a universe with an average expansion rate greater than zero must be geodesically incomplete in the past. But he also used an argument I hadn’t heard before: from the Second Law of Thermodynamics (entropy in a closed system doesn’t decrease). I think the argument was basically that the Second Law implies that we approach equilibrium, and in an infinitely-old universe we should therefore have reached equilibrium long ago, which we haven’t, so the universe began at some finite time in the past.
My attitude toward the above two premises is that (2) is completely uncertain, while the “obvious” one (1) is flat-out false. Or not even false, as I put it, because the notion of a “cause” isn’t part of an appropriate vocabulary to use for discussing fundamental physics. Rather, modern physical models take the form of unbreakable patterns — laws of Nature — that persist without any external causes. The Aristotelian analysis of causes is outdated when it comes to modern fundamental physics; what matters is whether you can find a formal mathematical model that accounts for the data. The Hartle-Hawking “no-boundary proposal” for the wave function of the universe, for example, is completely self-contained, not requiring any external cause.
Mostly Craig ignored this argument, which to me was the most important part of the debate. In the first rebuttal he said that the Hartle-Hawking model was indeed lacking something — a reason why the universe exists at all. To me this looks like confusing the cosmological argument with the argument from contingency, but since my objection applied to that case as well I didn’t raise that as an rebuttal. Rather, I pointed out that this response sailed right by my actual argument, which was that a self-contained physical model is all you need, and asking for anything more is completely unwarranted. To drive the point home, I elaborated on why things like “causes” and “explanations” make perfect sense for parts of the universe, but not for the universe itself: namely, that we live in a world with unbreakable patterns (laws of physics) and an arrow of time, but the universe itself (or the multiverse) is not one element of a much bigger pattern, it’s all there is. Finally in the closing speech WLC finally offered arguments in favor of the idea that the beginning of the universe implies a transcendental cause: (1) it’s a metaphysical principle; (2) if universe could pop into existence, why not bicycles?; and (3) there’s no reason to treat the universe differently than things inside the universe. To me, (1) isn’t actually an argument, just a restatement; and I had already explained why (2) and (3) were not true, and he didn’t actually respond to my explanation. So by the time my rebuttal came around I didn’t have much more new to say. Craig spent some time mocking the very idea that the universe could just “pop into existence.” I explained that this isn’t the right way to think about these models, which are better understood as “the universe has an earliest moment of time,” which doesn’t misleadingly appeal to our intuitions of temporal sequence; but my explanation seemed to have no effect.
The second premise of the Kalam argument is that the universe began to exist. Which may even be true! But we certainly don’t know, or even have strong reasons to think one way or the other. Craig thinks we do have a strong reason, the Borde-Guth-Vilenkin theorem. So I explained what every physicist who has thought about the issue understands: that the real world is governed by quantum mechanics, and the BGV theorem assumes a classical spacetime, so it says nothing definitive about what actually happens in the universe; it is only a guideline to when our classical description breaks down. Indeed, I quoted a stronger theorem, the “Quantum Eternity Theorem” (QET) — under conventional quantum mechanics, any universe with a non-zero energy and a time-independent Hamiltonian will necessarily last forever toward both the past and the future. For convenience I quoted my own paper as a reference, although I’m surely not the first to figure it out; it’s a fairly trivial result once you think about it. (The Hartle-Hawking model is not eternal to the past, which is fine because they imagine a universe with zero energy. In that situation time is an approximation rather than fundamental in any case — that’s the “problem of time” in quantum gravity.)
Sadly, Craig never responded to my point about the QET. Instead, he emphasized another “theorem” in a paper by Aron Wall. This is a great paper, well worth reading — but it doesn’t say what Craig wants it to say, which I was only able to check after the debate. Wall (like BGV) proves theorems that apply to semiclassical gravity (classical spacetime with propagating quantum fields — see comment from Aron below), and then speculates “the results may hold in full quantum gravity” and “there is a reasonable possibility that the Penrose singularity theorem can be proven even in the context of full quantum gravity.” As good as the paper is, proving a theorem in the semiclassical case and then opining that it is probably extendable to the full quantum gravity case does not actually represent a “theorem” about the quantum case. And in fact I think it’s highly unlikely to be extendable in the sense Craig wants it to be, since the QET says that’s impossible (unless the universe has zero energy or a time-dependent Hamiltonian, in which case it’s easy to avoid eternity). But I had never seen Wall’s paper before, and Craig didn’t give a precise statement of the purported theorem, only the above quote about “reasonable possibility”; as a result I didn’t know the range of applicability of the “theorem” or its assumptions, so chose not to talk about it rather than making guesses. That was probably a strategic mistake on my part.
While I’m lingering over my mistakes, I made a related one, when Craig emphasized a recent paper by Anthony Aguirre and John Kehayias. They examined the “emergent universe” scenario of George Ellis and Roy Maartens, in which the universe is in a quasi-static pre-Big-Bang state infinitely far into the past. Aguirre and Kehayias showed that such behavior is unstable; you can’t last in a quasi-static state for half of eternity and then start evolving. Personally, I didn’t think this was worth talking about; I completely agree that it’s unstable, I never promoted or defended that particular model, and I just didn’t see the relevance. But he kept bringing it up. Only after the debate did it dawn on me that he takes the specific behavior of that model as representative of any model that has a quantum-gravity regime (the easiest way out of the “beginning” supposedly predicted by the BGV theorem). That’s completely false. Most models with a quantum-gravity phase are nothing like the emergent universe; typically the quantum part of the evolution is temporary, and is surrounded on both sides by classical spacetime. But that’s so false that I didn’t even pick up that WLC was presuming it, so I never responded. Bad debater.
The other argument from Craig in favor of the universe having a beginning comes from the fact that entropy is increasing, in accordance with the Second Law. This is another case where it took me a while to understand the point he was trying to get at. To me, it is perfectly obvious and well-understood that the Second Law comes about because of the configuration of matter in our local region of universe, not because of some ironclad fundamental law. (Otherwise Ludwig Boltzmann lived in vain — and I have his tombstone right up there on my blog header.) A theory like my model with Jennifer Chen tries to explain how the Second Law emerges in local regions of the universe, by showing how a universe with no equilibrium state can evolve forever (rather than settling down), and entropy will naturally increase both in the far past and the far future. Craig seems to think that the Second Law should be absolute, so that models like ours are ruled out because entropy doesn’t increase monotonically — i.e. they “violate” the Second Law. (Unless I’m still misunderstanding his point — his presentation was uncharacteristically muddled here.) This is a pretty straightforward misunderstanding of the origin of the Second Law and the point of our model, although to be fair I caught on too late to present a strong counterargument.
It was interesting that Craig spent so much time talking about the Carroll-Chen model, when I wouldn’t have brought it up at all if left to my own devices. I think the model is very useful as an illustration of an interesting fact: you can derive a natural dynamical origin of the Second Law in a universe that creates new entropy without bound by creating regions of space that look like our Big Bang. But I’m the first to admit that it’s speculative, and especially that the process of baby-universe creation is ill-understood, if it’s possible at all. So I probably wouldn’t have dwelt on it, but Craig really went to town on the model. Unfortunately, nearly everything he said about it was just wrong. First, he tried to claim that having a moment of time in the history of the universe when entropy was lowest counts as a “thermodynamic beginning,” even if there is more universe in both direction of time around that moment. That’s quite an innovative definition (to be polite), but more importantly that kind of “beginning” has nothing to do with the kind of “beginning” where God would create the universe. I made this point, but it wasn’t answered. Relatedly, he seemed to think it was a glaring mistake (or perhaps intentionally subterfuge?) that on one picture of our model I had the “time” axis have only one arrow, while on another version of the picture I put arrows pointing in both directions. I apologize for being sloppy, but it’s neither a mistake nor a dastardly plot; either version is acceptable, because you have a time coordinate that runs monotonically from -infinity to +infinity, but the direction of entropy increase (that defines the arrow of time) is not monotonic. Next, he tried to claim that our model violated unitarity (conservation of quantum information), which is flatly wrong. He supplied two pieces of evidence, in the form of quotes from Stephen Hawking and Chris Weaver. But the Hawking quote was completely out of context; he was talking about the fact that he no longer thought that wormholes would lead to violation of unitarity in black-hole evaporation, nothing to do with cosmology. And the Weaver quote that Craig read had nothing to do with unitarity at all; it merely pointed out that the process of baby-universe creation is speculative and not well-understood, which I’m the first to admit. Again — I didn’t actually hold up this model as a solution to anything, but he felt the need to attack it, so I had to defend its honor a little bit.
In contrast, I wanted to talk about a model developed by Anthony Aguirre and Stephen Gratton. They have a very simple and physically transparent model that (unlike my theory with Chen) imposes a low-entropy boundary condition at a mid-universe “bounce.” It’s a straightforward example of a perfectly well-defined theory that is clearly eternal, one that doesn’t have a beginning, and does so without invoking any hand-waving about quantum gravity. I challenged Craig to explain why this wasn’t a sensible example of an eternal universe, one that was in perfect accord with the BGV theorem, but he didn’t respond. It wasn’t until the talks on the following day that Craig’s teammate James Sinclair admitted that it seemed like a perfectly good model to him.
But again — my main point was not to push this or that specific model, but to argue that it’s the models that matter, not some general theorem in a regime we don’t pretend to understand. So I listed a bunch of plausible-looking eternal cosmologies. The point is not that all or some of these models is perfect; it’s that they’re eternal. So we should judge them on their merits, rather than claiming to have general arguments that there are no such things. (It’s as if WLC has a powerful general theorem against heavier-than-air flying machines, while airplanes keep buzzing overhead.) On occasion it would be as if Craig admitted that there were indeed eternal cosmologies, but they were all ruled out for various unspecified other problems. That sounds like a suspiciously far-reaching claim, but one that is hard to directly dispute without any details being presented. More importantly, it’s beside the point. Which, in case it isn’t yet clear, is that it’s the models that matter, not any general theorems. If there are some cosmological models that are eternal but have other problems, there’s no reason to stop looking for other models that are also eternal but don’t have those problems. This is a case where working scientists are quick to admit that we don’t know the answer, so we shouldn’t stop considering all legitimate possibilities.
The fine-tuning argument proceeded in a more straightforward way. Unlike the cosmological argument, where Craig presented a few twists I hadn’t heard before (though he may have used them in other debates, I don’t know), the fine-tuning presentation was pretty standard. I acknowledged that, unlike the cosmological argument that is based on outdated metaphysics, the fine-tuning argument is a respectable scientific claim: two models trying to account for some data. But I gave five reasons why it was nevertheless not a good argument for theism:
- We don’t really know that the universe is tuned specifically for life, since we don’t know the conditions under which life is possible.
- Fine-tuning for life would only potentially be relevant if we already accepted naturalism; God could create life under arbitrary physical conditions.
- Apparent fine-tunings may be explained by dynamical mechanisms or improved notions of probability.
- The multiverse is a perfectly viable naturalistic explanation.
- If God had finely-tuned the universe for life, it would look very different indeed.
Craig didn’t respond to 2. or 3. here. To counter 1. he simply noted that other physicists disagreed with me, which again really isn’t an argument; he didn’t offer any suggestion that we actually do know the conditions under which life can and cannot form. Against 5. he invoked an argument by Robin Collins that the universe is optimized for “discoverability,” at least when we consider the known physical parameters. To me this argument is completely implausible right on the face of it, since it’s trivially easy to imagine ways to make it easier to discover the universe (just make the Higgs boson lighter!). But I knew Collins was going to give a full discussion of that argument the next day, so I saved my response until then.
In my first speech I used 5. above as a launching pad to make a bigger point: the real reason theism isn’t taken seriously is because it’s completely ill-defined. If we would presume to contemplate theism from an intellectually honest perspective, we would try to decide what kind of universe we would expect to live in if theism were true; then we would do the same for naturalism; and finally we would compare those expectations to the real world. But when we do that we find theistic expectations failing to match reality over and over again. Now, I know perfectly well (from experience as well as from cogitation) that you can never make headway with theists by claiming “If God existed, He would do X, and He doesn’t” (where X is “prevent needless suffering,” “make His existence obvious,” “reveal useful non-trivial information to us,” “spread religious messages uniformly over the world,” etc.) Because they have always thought through these, and can come up with an explanation why God would never have done that. (According to Alvin Plantinga, our world — you know, the one with the Black Death, the Holocaust, AIDS, Hurricane Katrina, and so on — is “so good that no world could be appreciably better.”) But these apologetic moves come at a price: they imply a notion of theism so flexible that it becomes completely ill-defined. That’s the real problem. Craig’s way of putting it is to suggest that God is “like the cosmic artist who wants to splash his canvas with extravagance of design.” That’s precisely why naturalism has pulled so far ahead of theism in the intellectual race to best model our world: because it plays by rules and provides real explanations for why the world is this way rather than that way.
Against the multiverse, Craig’s major argument (surprisingly) was the Boltzmann Brain problem. I say “surprisingly” because it’s such an easy argument to rebut. Sure, Boltzmann Brains are a problem — for those models with a Boltzmann Brain problem. Not all models have them! And a good modern multiverse cosmologist focuses on those models that avoid them. In this sense, the BB problem is a good thing; it helps us distinguish viable models from non-viable ones. As far as I can tell, this straightforward response was completely ignored by Craig. He just kept repeating that Boltzmann Brains were really bad things. He aimed this criticism particularly at the Carroll-Chen model, which I would say is very bad aim; it’s much less likely that BB’s are a problem in our scenario than in most other multiverse theories, since you actually produce baby universes (with potentially billions of observers) more frequently than you produce individual Boltzmann Brains. But I didn’t emphasize that point, since my goal wasn’t to defend that particular model.
As an aside, the Boltzmann Brain discussion illustrated a problem with the debate as a whole: it was too technical (and I think mostly on WLC’s side, although I deserved some of the blame). I had prepared a single slide about the topic of BB’s, but upon reflection I figured that many people wouldn’t be familiar with the term, so I replaced it with “observers as random fluctuations.” But Craig just plowed right into the technicalities, without trying to explain what the Boltzmann Brain problem really was. When my term came I gave a one-sentence definition, but in retrospect that wasn’t really sufficient, so on Saturday (where we both gave five-minute responses to a series of 40-minute talks by the four other speakers) I took a few minutes to give a more careful explanation. It’s probably an inherent flaw of the format; if a speaker takes a minute to do a bit of pedagogy rather than argumentation, the audience benefits but the speaker suffers. So the game theory tells you to be obscure, to the general detriment.
A couple of words about the rebuttal speeches in particular. Each of us pulled one “gotcha” move in the rebuttals; mine worked, his didn’t (in my opinion, of course). His referred to fine-tuning: he found a quote by me saying that the low entropy of the early universe seems finely-tuned. Which is true! But he claimed that I had said we didn’t know whether fine-tuning was real. That part is completely false. I had said we didn’t know that fine-tuning for life was real; indeed, the words “for life” were italicized on my slide. And it’s perfectly obvious that the fine-tuning of our initial entropy isn’t necessary for life; the entropy could have been fantastically larger than it actually was and life still could have arisen. (For example, you could imagine a universe with our Solar System as it essentially is, but otherwise in thermal equilibrium.)
On my part, I knew that WLC liked to glide from the BGV theorem (which says that classical spacetime description fails in the past) to the stronger statement that the universe probably had a beginning, even though the latter is not implied by the former. And his favorite weapon is to use quotes from Alex Vilenkin, one of the authors of the BGV theorem. So I talked to Alan Guth, and he was gracious enough to agree to let me take pictures of him holding up signs with his perspective: namely, that the universe probably didn’t have a beginning, and is very likely eternal. Now, why would an author of the BGV theorem say such a thing? For exactly the reasons I was giving all along: the theorem says nothing definitive about the real universe, it is only a constraint on the classical regime. What matters are models, not theorems, and different scientists will quite naturally have different opinions about which types of models are most likely to prove fruitful once we understand things better. In Vilenkin’s opinion, the best models (in terms of being well-defined and accounting for the data) are ones with a beginning. In Guth’s opinion, the best models are ones that are eternal. And they are welcome to disagree, because we don’t know the answer! Not knowing the answer is perfectly fine. What’s not fine is pretending that we do know the answer, and using that pretend-knowledge to draw premature theological conclusions. (Chatter on Twitter reveals theists scrambling to find previous examples of Guth saying the universe probably had a beginning. As far as I can tell Alan was there talking about inflation beginning, not the universe, which is completely different. But it doesn’t matter; good scientists, it turns out, will actually change their minds in response to thinking about things.)
I very much hope that I hammered these points home enough to help clarify issues in the minds of listeners/readers. But from Craig’s (lack of) reaction, and from the online discussion from his supporters, I doubt it will make any difference. He will continue to quote Vilenkin saying the universe probably had a beginning, which is fine because that’s what Vilenkin actually thinks. He will not start adding in the fact that Guth thinks the universe is probably eternal, nor will he take the even more respectable position of not relying on people’s individual opinions at all and simply admitting that we don’t have good scientific reasons to think one way or the other at the moment. But we’ll see. (And to reiterate: I think the whole discussion is enormously less important than the bigger point that a “cause” is completely unnecessary even if the universe did have a beginning.)
For my closing statement, I couldn’t think of many responses to Craig’s closing statement that wouldn’t have simply be me reiterating points from my first two speeches. So I took the opportunity to pull back a little and look at the bigger picture. Namely: we’re talking about “God and Cosmology,” but nobody really becomes a believer in God because it provides the best cosmology. They become theists for other reasons, and the cosmology comes later. That’s because religion is enormously more than theism. Most people become religious for other (non-epistemic) reasons: it provides meaning and purpose, or a sense of community, or a way to be in contact with something transcendent, or simply because it’s an important part of their culture. The problem is that theism, while not identical to religion, forms its basis, at least in most Western religions. So — maybe, I suggested, tentatively — that could change. I give theists a hard time for not accepting the implications of modern science, but I am also happy to give naturalists a hard time when they don’t appreciate the enormous task we face in answering all of the questions that we used to think were answered by God. We don’t have final answers to the deep questions of meaning and fulfillment and what it means to lead a good life. Religion doesn’t have the final answers, either; but maybe it has learned something interesting over the course of thousands of years of thinking about these issues. Maybe there is some wisdom to be mined from religious traditions, even for naturalists (which everyone should be).
More than once of the course of the weekend I spoke conciliatory-sounding words about how we’re really all in this together, theists and naturalists, trying to understand the deep questions in a confusing world. And I meant all of it, in complete sincerity. I will be absolutely uncompromising about what I think the truth is concerning questions of substance; but I don’t ever want to start thinking of people who disagree with me about those questions as my enemies. Many times in New Orleans, people on “the other side” came up after my presentations (in which I said that their most deeply held beliefs had been definitively refuted by the progress of modern science) and thanked me, saying how much they appreciated my ideas and that I had given them something to think about, even if they remained quite resolute in their beliefs. Not every single person was so gracious, but the vast majority. I admire those folks, and I hope I can be as sincere and open when people who I disagree with are speaking in good faith.
To me, Craig’s best moment of the weekend came at the very end, as part of the summary panel discussion. Earlier in the day, Tim Maudlin (who gave an great pro-naturalism talk, explaining that God’s existence wouldn’t have any moral consequences even if it were true) had grumped a little bit about the format. His point was that formal point-counterpoint debates aren’t really the way philosophy is done, which would be closer to a Socratic discussion where issues can be clarified and extended more efficiently. And I agree with that, as far as it goes. But Craig had a robust response, which I also agree with: yes, a debate like this isn’t how philosophy is done, but there are things worth doing other than philosophy, or even teaching philosophy. He said, candidly, that the advantage of the debate format is that it brings out audiences, who find a bit of give-and-take more exciting than a lecture or series of lectures. It’s hard to teach subtle and tricky concepts in such a format, but that’s always a hard thing to do; the point is that if you get the audience there in the first place, a good debater can at least plant a few new ideas in their heads, and hopefully inspire them to take the initiative and learn more on their own.
I completely agree. Events like this are valuable, not because they are efficient ways to find the truth, nor even because there is any reasonable chance of changing the minds of people who are relatively secure in their beliefs (on either side). It’s because there are a lot of people who are not secure in their beliefs, or at least are curious and willing to listen to a variety of ideas. If we think we have good ideas, we should do everything we can to bring them to as many people as possible. I think science and naturalism include some pretty awesome ideas, and I’m happy to share them with as many different people as I can.
p.s. Sorry I didn’t talk about Saturday’s talks, in which Tim Maudlin discussed the relationship between theism and morality (claiming there isn’t any), Alex Rosenberg drew connections between thermodynamics and natural selection to argue that theism is incompatible with Darwinism, Robin Collins argued that the discoverability of the universe is evidence for theism, and James Sinclair talked about notions of time and the origin of the universe. But I’m kind of all talked out on this topic for right now.
Sean, I only caught part of the debate, but in the part I saw, your performance was excellent. I do have a criticism, though. I understand that you got to choose the respondents on your side, and I wish that you would have chosen at least one person who was not a white male. It was a little disheartening seeing another panel at a major intellectual event completely consisting of white men. Something to think about for next time (if there is one).
If colleagues disagreeing with you on certain topics is grounds for completely dismissing your argument, then where does that leave WLC and theism in general? That’s a whopping double standard that WLC is presenting. It all comes back to a fundamental misunderstanding of science and a perceived threat from scientific facts. In WLC’s mind “Science is against us”, when it is in fact “The facts are against us”.
Tarun,
There are quite a few panels in similar formats on similar subjects in which Sean has debated people from various races. I think it’s one of the first videos you find when you do a youtube search. I think it’s probably hard to find a non-white person who will agree to debate southern baptists in the heart of the south. If I were black, then I would probably pass given the history.
Sean Carroll: “More than once of the course of the weekend I spoke conciliatory-sounding words about how we’re really all in this together, theists and naturalists, trying to understand the deep questions in a confusing world.”
Really Sean? The last thing WLC wants is to understand anything that puts his bronze age world view in doubt. And why worry about poverty, sickness, war, climate change, none of this matters because Jesus is coming any day now.
Craig: “The plausibility of Christian eschatology vis à vis the projections of physical eschatology is inherently bound up with one’s ontology. If, as physical cosmology itself intimates, there exists a personal, transcendent agent who created the universe with all its natural laws and boundary conditions, and if, as the historical evidence suggests, that agent has raised from the dead Jesus of Nazareth, who promised his eschatological return, then it is eminently rational to entertain “the blessed hope” of Christian eschatology, while accepting the findings of physical eschatology as more or less accurate projections based on present conditions.”
“More than once of the course of the weekend I spoke conciliatory-sounding words about how we’re really all in this together, theists and naturalists, trying to understand the deep questions in a confusing world.”
Really?
William Lane Craig: “The plausibility of Christian eschatology vis à vis the projections of physical eschatology is inherently bound up with one’s ontology. If, as physical cosmology itself intimates, there exists a personal, transcendent agent who created the universe with all its natural laws and boundary conditions, and if, as the historical evidence suggests, that agent has raised from the dead Jesus of Nazareth, who promised his eschatological return, then it is eminently rational to entertain “the blessed hope” of Christian eschatology, while accepting the findings of physical eschatology as more or less accurate projections based on present conditions.”
http://www.reasonablefaith.org/rf-gear-and-the-return-of-christ
The Craig type of theist is defined by the hope that our natural world will be destroyed by God, perhaps even tomorrow, so why bother?
Craig is also a proponent on his site of sexual-orientation conversion therapy. So much for “trying to understand” and “all in this together”.
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Triptych,
That qualifies as a response? Dr. Carroll was refering to the fact the common sense intuitions and everday descriptions do not apply in fundamental physics (such as quantum mechanics). That is not an “arbitrary” dismissing of the causal principle, it’s based on an informed understanding of contemporary physics.
So, if you call a claim “metaphysical”, then it must, by definition, apply to all of reality? This strikes me as a cheap way of trying to dismiss all the evidence to the contrary as irrelevant. Perhaps this is just the scientist in me, but if I heard of a metaphysical claim that was applied broadly and knew of some phenomena that doesn’t fit with it (and quantum theory is well supported by thousands of experiments, and confirmed with excellent percision, as Craig himself admits) I would conclude either A) This claim does not apply universally or B) This claim is false.
“This was to say that if the causal principle really doesn’t apply to all reality, than we should be seeing anything and everything popping into existence. The fact that we don’t see this strongly disconfirms your objections to the first premise.”
This is a complete straw man. Dr. Carroll did not say the causal principle is entirely false. I would say that talk of efficient and material causes are quite useful with respect to everday macroscopic objects, but fundamental physics is not like that at all. But the idea that “anything and everything would pop into existence…” is also absurd.
Just because there is no meaningful talk of “causes” at some level of physics, it does not follow that therefore the system therefore lacks ANY limitations as to what could or could not occur. Notice that Dr. Craig is equivocating on the word “cause” here. In his various writings and Q&A submissions, he defines cause as “whatever brings about the existence of some object.” Now he’s oh-so-conveniently tacking on an additional stipulation that these causes are also contrainsts to a system.
Certainly causes CAN be constraints to the working of some system, but once again he is applying this assumption very broadly when it is not at all clear that “causes” are the only neccessary and sufficient means of constraining a system from certain possibilities. Remember, Carroll’s point is that at fundamental physics we still observe mathematically described patterns.
Neither of Dr. Craig’s responses deals with the issues Dr. Carroll raised here and only conform to the problems Craig had with respect to just simply repeating his same points but not addressing the substance of his critique.
Cheers!
Oops, many questions have accumulated and I’ve been stuck with actual work. Some very quick comments:
— On tensed vs. tenseless theories of time (A-theory vs. B-theory): I thought this would be far too recondite to tackle in any meaningful way in the course of a debate like this. While I strongly hold to the tenseless view, I don’t think the tensed view is manifestly crazy, so it’s not the most compelling angle to take in this situation.
— Counter Apologist, about the nature of spacetime: In quantum mechanics, we don’t describe the world in terms of spacetime, we describe it in terms of a wave function (or quantum state). In quantum gravity we expect spacetime to be an approximation to the quantum state in certain circumstances, but not always. That’s “the classical regime.”
— Lyle, on discoverability: Collins didn’t want to defend the claim that the laws of physics are optimized for discoverability (although presumably that’s the claim he should be defending), but he did claim that the parameters of physics were thus optimized. At least, that was one of the theses on his slide.
— Lucy Harris: A theorem is a logical demonstration of a claim of the form “under these assumptions, this conclusion necessarily follows.” A model is totally different; it’s a hypothetical structure (like a set of equations representing particles or fields) that tries to represent some behavior of the universe.
— Ben: I don’t agree that the best models are those that are not past-eternal. Nor does Alan Guth, or Leonard Susskind, or Roger Penrose, or any number of other people. But we all admit we don’t know, so studying different models is highly advisable.
— Janet: I think it’s easy to define naturalism. In practice it amounts to three ideas: 1. There is a single reality, the natural world. 2. The natural world obeys rules. 3. We can learn something about those rules through the practice of science.
— About causal principles and popping into existence: I never said that the causal principle (whatever that is supposed to be) applied within the universe but not to it. Rather, I said that this notion of causality is not the right way to think about fundamental physics at all; instead, you should think about unbreakable patterns (laws of nature). Then I explained why causation is a useful approximation for macroscopic situations within our universe, but wouldn’t apply to the creation thereof. (The universe is not one element of a larger pattern.)
“I never said that the causal principle (whatever that is supposed to be) applied within the universe but not to it. ”
I think the problem here is ambiguity in the phrase “the causal principle.” I believe what Craig means by this is the principle “ex nihilo, nihil fit”–out of nothing, nothing comes. If the universe began to exist, then it either came from nothing or had a transcendent cause (if it didn’t begin to exist then the Kalam argument fails on other grounds). If “ex nihilo, nihil fit” is true, then it had a transcendent cause, because being does not comes from non-being. That is not a principle of physics, but metaphysics, and if challenged needs to be done on philosophical grounds. Physics qua physics would not seem be be a basis for challenging it due to the constraints of methodological naturalism.
Similarly with the Principle of Sufficient Reason. It can’t be challenged based on “how physics is done” or because under methodological naturalism the universe “is all there is” because it is “meta” physical–beyond physics. If it is true, then the universe cannot be a brute fact without need of explanation–it either exists due to an external cause or exists due to the necessity of its own nature. This has to be challenged philosophically, and physics qua physics doesn’t have the resources to do it.
@Augustine1938. Who says there was ever nothing? Who says the universe doesn’t necessarily exist?
Lucy,
“Who says there was ever nothing?”
Well, Lawrence Krauss entitled his book “A Universe from Nothing.”
“Who says the universe doesn’t necessarily exist?”
My impression is that is what Dr. Carroll was saying–that the universe’s existence is not explained by the necessity of its own nature, but is a brute fact that requires no explanation (and that the whole concept of an “explanation” should not be applied to the universe as a whole). I’m not aware of any major philosopher or physicist who holds that the particular combination of quarks and fields that constitutes our universe exists necessarily. Maybe you have an argument to support the notion that it does?
@Augustine1938
“ex nihilo nihil fit” can mean a lot of different things. In Lucretius, it basically amounts to saying the number of atoms of each type is conserved. To the extent that this principle has any basis in fact, it is an approximation that applies to nonrelativistic, stable particles (e.g. electrons and common types of nuclei at room temperature.) The more generalized version of this is conservation of energy, which actually needs further generalization before it’s actually true — even before getting into the speculative bits of cosmology. As it happens, Hartle-Hawking does not violate any version of conservation of energy which physics has given us a reason to believe.
But, you say you’re not talking about physics, you mean something else by “ex nihilo nihil fit”. Fine but:
1) I really don’t think that’s a charitable reading of Lucretius. His notion of “nothing” was the void, which pretty clearly had geometry and spatial extent — and therefore looks a lot more like the physicist’s quantum vacuum than the modern philosopher’s “nothing.”
2) We have zero experience with the philosopher’s “nothing.” If you insist on describing non-past-eternal cosmologies as having a state of “nothing” at a “time” before *spacetime* existed, who’s to say what can and cannot arise from such a state? (Incidentally, this further undercuts the idea that Lucretius meant the same thing as modern philosophers by “nothing:” Since Lucretius was a pretty thoroughgoing empiricist it seems odd that he would use as the bedrock principle of his physics, a statement about what would arise from a state that had never been observed.)
So in sum, to the extent we have any reason to believe “ex nihilo nihil fit” or anything like it, it comes from physics. The physically well motivated generalizations of this statement take the form of conservation laws, which are not violated by cosmologies like Hartle-Hawking. You are free to try to save the causal principle after it has been subsumed by more accurate physics, by calling it a “metaphysical principle,” but having done so, we are left with no reason to believe it anymore. To quote a more modern thinker: “What can be asserted without evidence can be dismissed without evidence.”
Augustine1938,
The problem is not that contemporary physics disputes the validty of philosophical doctrines like ‘ex nihilo nihil fit.” Rather the problem is that contemporary physics says that these notions of ‘efficient cause for the universe” and universes “popping into existence from nothing” are incorrect ways of thinking about the origins of the universe.
Physics isn’t saying these doctrines are wrong, only that they do not apply. Therefore, any argument beginning with these doctrines and applying them to our universe will be false (or at the very least, strongly misleading).
P.S. On the principle of sufficient reason, there is one philosopher who argues there is an interpretation of this doctrine which is MORE compatible with naturalism than theism. See here:
http://exapologist.blogspot.com/2012/05/psr-for-naturalists.html
Cheers!
@Ausgustine1938
“I’m not aware of any major philosopher or physicist who holds that the particular combination of quarks and fields that constitutes our universe exists necessarily. ”
Al Ghazali (probably the most important expositor of the Kalam Cosmological argument) considered the distinction you are trying to make between brute fact and necessary being meaningless. Does that count?
Sean, perhaps I sound obstinate on the idea of causation at the moment, but I could use a little clarification on this if someone is willing:
“I never said that the causal principle (whatever that is supposed to be) applied within the universe but not to it. Rather, I said that this notion of causality is not the right way to think about fundamental physics at all; instead, you should think about unbreakable patterns (laws of nature).”
So is this to argue then that causation may be an emergent principle of our universe as one might hold time? That would seem more conducive with how the debate was stylized, but I might have missed that because it’s such a hard pill to swallow since we depend on it and the principle of sufficient reason so much for our logic. Maybe it’s just because I’m not a physicist, but as logic is such a key tool for our empirical studies, I have an extremely hard time envisioning how we would explore these questions with some of our logical pillars thus shaky.
Perhaps I could envision it in a mathematical sense, and perhaps without a strained aneurism hah, but again, I think this is going to be difficult for most of us unless we can see how this could be so, or how someone could even begin to think about such matters beyond pure abstraction. And perhaps for someone who’s done the math, this is intuitive and demands little attention, but I think the everyday public and especially everyday theists will stubbornly feel resistance until they can see how so. I still remember the ideas blowing my mind in the college course where they were introduced, and obviously they still do now.
Thanks for your patience and willingness to continue the conveyance of knowledge.
Josh– That’s right, it’s an emergent approximation, just as classical mechanics is an approximation to quantum mechanics (and yet we go through every day talking as if things actually have positions and velocities).
I don’t have a perfect reference, but Bertrand Russell makes some of the major points (although I don’t agree entirely):
http://www.readbookonline.net/readOnLine/22891/
I think he misses the important step that causality is still important in certain situations as an emergent approximation.
Sean:
I think there is a simple answer to why bicycle did not come out of big bang. I am surprised that you did not answer it like this, unless there is a catch in my argument which I am missing. Universe had to go through the whole process, first make quarks, electrons, Higgs, then atoms such as iron, then molecules such as plastics, rubber etc. This is how it took place according to current physics. Probability of getting all the atoms coming together in the form of a bicycle would be infinitesimally small! Nobody can build a bicycle in his garage from scratch without getting parts from a factory! So the question is ridiculous.
Ray: “We have zero experience with the philosopher’s “nothing.” If you insist on describing non-past-eternal cosmologies as having a state of “nothing” at a “time” before *spacetime* existed, who’s to say what can and cannot arise from such a state?”
Well, there is no “time” before spacetime existed, so it would be more proper to say that nonbeing was logically (not temporally) prior to the beginning of the universe. But you seem to adopt an epistemology in which our knowledge of metaphysics is dependent on “experience.” I don’t agree with that, since we have reliable knowledge not based upon experience (of abstract objects, mathematical concepts, laws of logic, etc), but that at least amounts to a philosophical objection to ex nihilo nihil fit, which is the type of objection that is necessary. An empirical objection or one based on how physics is done is a category error.
Ray: “Al Ghazali (probably the most important expositor of the Kalam Cosmological argument) considered the distinction you are trying to make between brute fact and necessary being meaningless. Does that count?”
I was looking for someone familiar with the concept of quarks and fields 🙂
Mason: “Physics isn’t saying these doctrines are wrong, only that they do not apply. ”
That’s the problem–physics qua physics has doesn’t have the resources to refute ex nihilo nihil fit or the PSR–these are fundamentally “beyond” (meta) physical (though it can be helpful if offering collateral support for or evidence against, say, the second premise of the Kalam–the universe began to exist–or the second premise of the Leibnizian contingency argument–the universe is contingent).
Mason: “On the principle of sufficient reason, there is one philosopher who argues there is an interpretation of this doctrine which is MORE compatible with naturalism than theism. See here”
Thanks, I need some time to study that, but that’s the sort of objection that is required to the PSR–philosophical, not scientific.
Geez, Sean you made me hungry. How much mass did you gain while in New Orleans?
Augustine1938,
“That’s the problem–physics qua physics has doesn’t have the resources to refute ex nihilo nihil fit or the PSR–these are fundamentally “beyond” (meta) physical (though it can be helpful if offering collateral support for or evidence against, say, the second premise of the Kalam–the universe began to exist–or the second premise of the Leibnizian contingency argument–the universe is contingent).”
You missed the rest of my statement, and therefore, the key point of the objection. Sure, physics doesn’t refute this philosophical docrtine- BUT the physics does strongly suggest these doctrines are poor and inaccurate representations of what happens at the origin of the universe and therefore – do not apply.
You can make a good philosophical case that some doctrine is logically valid or reasonable – but that hardly means that doctrine necessarily applies to the phenomena in question. Which is why the physics IS still relevant to this discussion about origins.
“Thanks, I need some time to study that, but that’s the sort of objection that is required to the PSR–philosophical, not scientific.”
Well, yeah. I never said this was a scientific claim, it was a philosophical argument. I just thought that might be of interest to you.
Cheers!
There is a common objective in all of this—the relentless pursuit of the truth and both sides should be respectful to each other in this endeavor. Dr. Carroll, in your definition of naturalism to Janet, a Christian fully agrees with #2 and #3; we just believe through faith and reason that you left out something very important in statement #1! Though out of scope for this debate, I think the greater mystery for naturalists lies not in cosmology, but how inanimate matter “evolved” into life. This is the strength of the Design argument. Constrained to only using the tool of chance, the mathematical probabilities quickly become absurd. Best wishes to your sir, in your continued search for answers.
Mason: “You missed the rest of my statement, and therefore, the key point of the objection. Sure, physics doesn’t refute this philosophical docrtine- BUT the physics does strongly suggest these doctrines are poor and inaccurate representations of what happens at the origin of the universe and therefore – do not apply.”
Thanks, I should have made that clearer. In my view physics–limited as it is to methodological naturalism–does not have the resources to state that ex nihilo nihil fit or the PSR “do not apply” to the universe or its origin. Indeed, in that case it would be operating as “meta-meta-physics”– pronouncing on the applicability of metaphysical doctrines. Those doctrines, by their very definition, apply to anything that exists, which would obviously include the universe. Now, those doctrines may be wrong, but they need to be refuted philosophically. Physics in this case is handmaiden to philosophy–it can provide useful evidence for philosophy to work with (e.g., provide support or evidence against a premise in a philosophical argument) but must defer when the ultimate questions are at issue.
BA Brightlight,
“I think the greater mystery for naturalists lies not in cosmology, but how inanimate matter “evolved” into life.”
Granted we do not have a complete understanding of the biochemical pathways in which the origin of life occured, but refering to this phenomena as a “mystery” strikes me as obviously false. There is plenty of literature on this topic and I suggest delving into that literature.
“This is the strength of the Design argument.”
No, no it’s not. You raised question for which naturalists have an incomplete answer. This is very far from providing strength to any design argument. This is of course to say nothing of the fact that design “theorists” have thus far presented no testable scientific theories of their own, or provided any mechanisms for design. Critiquing naturalistic explanations does not automatically imply that design or theism wins by default.
“Constrained to only using the tool of chance, the mathematical probabilities quickly become absurd. ”
I’m not at all sure how to interpret these statements. By “constrained” are you refering to (A) the physical processes for the origin of life, or (B) the methods scientists use to research that phenomena? Either way, it is obviously false. Sure, there are a number of stochastic factors relating to origin of life scenarios, but recent literature has shown that these early macromolecules and proto-cellular replicators follow deterministic chemical pathways and were agents of selective pressure.
In reference to “mathematical probabilities”, I don’t think you realized the contradtiction you made here. You speak of these probabilities, I presume, to argue that origin of life is highly improbable given the naturalistic worldview- but at the same time you refer to this phenomena as a “mystery.” Which is it?
If origin of life scearios are “mysertious” then why place any confidence in probability claculations, given such limited data? And even it if were mathematically improbable- how does theism perform any better?
Additionally, I am curious as to how these probabilities are discussed. Typically these probabilities suggest that “The probability of this type of life existing on this planet is….”. But I agree with Neil Manson that this is a poor way to frame probability questions. A much better question would be “what is the probability of SOME type of life existing at SOME planet.” With the former question, you practically guarantee that your outcome will be extremely low- because your asking for a very narrowly specifice range of outcomes.
Cheers!
Augustine1938,
I’m afraid we’re just going to have to agree to disagree on this point.
“In my view physics–limited as it is to methodological naturalism–does not have the resources to state that ex nihilo nihil fit or the PSR “do not apply” to the universe or its origin.”
Firstly, exactly what kind of non-methodological naturalism “science” would you propose? Secondly, how would it fare any better with this question? Thirdly, I strongly disagree that physics cannot say that these doctrines “do not apply.”
There is currently no interpretation of any model in cosmology which reads as “a universe popping into existence uncaused out of nothing.” Granted, in popular writings physicists do tend to say such things- but as Carroll has pointed out in listing the various cosmological theories- this is not an accurate representation of what those equations and models describe.
I think the problem here is that apologists are trying to read certain philosophical doctrines into the physical models provided by scientists. What I interpret Carroll as saying is that these are theological interpretations are not accruately reflecting what the models actually say.
“Physics in this case is handmaiden to philosophy–it can provide useful evidence for philosophy to work with (e.g., provide support or evidence against a premise in a philosophical argument) but must defer when the ultimate questions are at issue.”
So physics can only support your theories, but never counteract them? This may be true, but again- this isn’t the point. I interpret Carroll as saying that (A) the physics does NOT support this doctrine “ex nihilo, nihil fit” and (B) the physics does counteract it insofar as our best scientific models do not provide any evidience this doctrine is an accurate description of reality.
“Those doctrines, by their very definition, apply to anything that exists, which would obviously include the universe. ”
Which is why I dislike this “by definition” game. Again, I find this is just not a useful way of talking about these issues. Why should we assume this doctrine applies to the creation of the universe when our current physics suggests that such descriptions of the origins is misleading?
Augustine1938: You claim that discussions of causation are metaphysical and that physics is not equipped to weigh in on what causation means and how, if at all, real it is. I suppose, then, that you assume that, whatever the correct description of causation is, it is an abstract logical principle independent from the laws of physics. But this is misguided.
By analogy, before quantum mechanics, a philosopher might have felt comfortable with a statement like “if some matter exists, then it must exist somewhere in space”. This seems logically necessary, and it might have seemed like a metaphysical statement that physics had no right to judge. However, physics has since shown us that some matter’s ‘location in space’ is an emergent phenomena, and not fundamentally real. Similarly, you might take it as a fact that causation is a metaphysical issue that physics can’t touch, but that’s only because you haven’t thought hard enough about it. Modern physics HAS reduced causation to an emergent macroscopic phenomena.
Take a simple example: One particle collides with another particle and sends it off flying. What caused the second particle to fly off? You might say the cause was the first particle colliding into it. But isn’t it also the caused by whatever sent that first particle flying towards it in the first place? Isn’t is also caused by every event in the history of that first particle? Isn’t it also caused by my second grade birthday party? Isn’t it also caused by everything in the past light cone of the event in question? There is no well defined notion of ’cause’ at the atomic level.
The macroscopic notion of cause is simply a fuzzy probabilistic statement about “well, I think if we removed event A from the timeline, then event B probably wouldn’t have happened, so we’ll call A a cause of B”. But this is not precise or well defined.
For these reasons and more, we can’t invoke arguments of ‘causation’ in domains where they become even less well defined.
What a bunch of brains and hearts in that talk; I just finished watching the q & a.
Gentle, considerate, genial, generous…
They must’ve been SO TIRED after the whole shebang…