Post-Debate Reflections

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.

Clockwise from top left: William Lane Craig, Alex Rosenberg, Sean Carroll, James Sinclair, Robert Stewart (Greer-Heard organizer), Tim Maudlin, and Robin Collins.

Clockwise from top left: William Lane Craig, Alex Rosenberg, Sean Carroll, James Sinclair, Robert Stewart (Greer-Heard organizer), Tim Maudlin, and Robin Collins. Screenshot by Maryanne Spikes.

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:

  1. 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.
  2. Fine-tuning for life would only potentially be relevant if we already accepted naturalism; God could create life under arbitrary physical conditions.
  3. Apparent fine-tunings may be explained by dynamical mechanisms or improved notions of probability.
  4. The multiverse is a perfectly viable naturalistic explanation.
  5. 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.

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149 Responses to Post-Debate Reflections

  1. Humanity Akbar says:

    Sean Carroll,

    maybe you could do a post on this?

    http://phys.org/news/2014-02-peeking-physicists-quantum-particles.html

  2. Avi says:

    @Jack Spell- I want to point out that quote from Vilenkin’s paper (Arrow of Time and the Beginning of the Universe) concerning the Aguirre Gratton Model is taken out of context. In the quote from page 4, Vilenkin was merely listing the necessary conditions for the AG model. Yes in a false vacuum if the bubble nucleating at t->-infinity will contract in a big crunch but only if the other conditions of the model are not taken into consideration. Vilenkin in the next paragraph continues to list these conditions. Like the important boundary condition at t=0 to be in a low entropy state and the thermodynamic arrow pointing away from this “initial” state. In the full AG model, no branch of the universe actually experiences contraction since both branches inflate “after” the initial state, so a big crunch doesn’t happen (as far as I’m aware in this model).

    By the end of the paper, Vilenkin’s comment of the AG model was somewhat promising:
    “The Aguirre-Gratton (AG) scenario assumes a de Sitter-like bounce with the thermodynamic arrow of time pointing in opposite directions away from the bounce. I argued that such a scenario may naturally arise in quantum cosmology with the Hartle-Hawking wave function of the universe. This choice of the wave function favors a de Sitter-like bounce in a vacuum state of the lowest positive energy density. The tunneling wave function, on the other hand, suggests that semiclassical spacetime is present only in one time direction from the bounce and favors the initial vacuum of the highest energy density.

    Even though the spacetime has no boundary in the AG model, it does include a hypersurface on which the low-entropy (vacuum) boundary condition must be enforced by some mechanism. This surface of minimum entropy plays the role of the beginning of the universe in this scenario.”

  3. Josh says:

    Hey Sean, thanks for taking the time to link me that page on causation. I’m surprised I haven’t ran into it before, so I’ll be sure to gobble it up!

  4. Jimmy says:

    Dr. Carroll,
    I very much enjoyed the debate and opportunity to learn about the cosmos. If you have already addressed this concern I apologize, but my reflections were the following:
    — You claim that premise one of the Kalam is patently false because models exist which predict a self contained system, and such model would purportedly refute the need for a transcendent cause. Additionally, I recall you using a similar type of reasoning by stating there are many “models” which serve to answer questions where our knowledge is deficient. Although it may be the case that cosmology, and science in general, proceeds in this manner, the central question of the debate concerned the current consensus. In other words, Dr. Craig was predominately using a model that is accepted by a majority of your peers as the best explanation of our cosmic beginning. Considering this is the best model we currently have [most widely accepted], even if it depends on classic space-time, how could you use models that are more problematic by which to justify a refutation of premise 1? Just so my point is clear: I do not understand how you justify a refutation of, “whatever begins to exist has a transcendent cause (i.e., does not cause itself), by postulating that there is a self contained model, when the model you describe is more problematic than the Borde-Guth-Vilenkin Theorem? Respectfully, it seems to me that this amounts to special pleading toward what theoretical physics could discover, but has yet to do so. Therefore, in the here and now, justification favors a model [theorem] which does support premise one, that whatever caused the universe’s beginning was something other than the universe.

  5. John says:

    Arahant, doesn’t that sort of concede Craig’s point? If we have no good reason to expect one thing or another about the whole Universe, then why shouldn’t just anything else have a first moment, why is it just Universes that get to do that? Why assume there is a meta-law to begin with?

  6. Augustine1938 says:

    Jimmy,

    I think you are misunderstanding the first premise of the Kalam. The first premise does not rely on the BGV theorem. The BGV theorem is used as support for the second premise, “the universe began to exist.” The first premise states that IF the universe began to exist, it had a transcendent cause. I understand Dr. Carroll’s objection to this premise to be that, as long as physics can come up with a self-contained model–even if that model shows the universe began to exist–then inquiring what “caused” the universe to begin to exist is “unwarranted” because it “isn’t part of an appropriate vocabulary to use for discussing fundamental physics.” I agree that under the strictures of methodological naturalism physics is not capable of dealing with issues of ultimate cause or explanation, so maybe it is “unwarranted” for the physicist in that sense. But, in my view, that is where the physicist has taken the baton as far down the field as he can and hands it off to the philosophers and the theologians, since questions of why the universe began to exist (or, in the case of the eternal cosmologies, why this particular contingent universe exists at all) are beyond the purview of physics qua physics. And of course even the physicist in his “off-hours” would be free to consider such metaphysical questions even if they are beyond the resources of physics to answer. I don’t see a good reason why inquiry has to stop because of a methodological constraint of physics.

    In regard to the second premise, I understand Dr. Carroll’s objection to be that there are models that are consistent with the BGV theorem that are past-eternal. Dr. Craig has argued that those models are inferior to the non-past-eternal models in terms of best fit to the available evidence, but Dr. Carroll says he is wrong about that, and that at this point it is inappropriate to say that the preponderance of the evidence favors either the past-eternal or non-past-eternal models, so judgment should be suspended until more evidence is in.

    Anyway, that is my layman’s understanding. I really enjoy these debates, because it provides an opportunity for we laymen to learn about the science in an interesting way.

  7. Jimmy says:

    Thank you for the response.
    It seemed that BVG would support premise 1 by implication in that the universe could not have caused itself on this model. I didn’t realize that the mere mathematical possibility of a model, or hypothetical model, could serve as a defeater? Surely if there was a theorem which most physicists agreed upon that indeed demonstrated a self contained system, that would weaken the probability of premise 1?
    Anyway, once again, I appreciate the response and agree with your ending statement: in regard to cosmology, I am most definitely a layman :)

  8. Augustine1938 says:

    Jimmy: “It seemed that BVG would support premise 1 by implication in that the universe could not have caused itself on this model.”

    I think the objection to a claim that “the universe caused itself” is just that the claim is incoherent. If you assume an A-theory of time, I think premise 1 is self-evident. But I believe Dr. Carroll adopts the B-theory of time.

    Jimmy: “I didn’t realize that the mere mathematical possibility of a model, or hypothetical model, could serve as a defeater?”

    With regard to premise 1, I agree. A model with non-past-eternality, like Hartle-Hawking, can’t serve as a defeater to premise 1, assuming an A-theory of time. A model allowing for past eternality that is consistent with the BGV theorem would seem to weaken premise 2, however (though it wouldn’t rule it out, since there are other models that are non-past-eternal, and there is philosophical support for premise 2 in the impossibility of actual infinites).

    Jimmy: “Surely if there was a theorem which most physicists agreed upon that indeed demonstrated a self contained system, that would weaken the probability of premise 1?”

    I think a model with non-past-eternality could only be considered self-contained on a B-theory of time. I believe it is true that on a B-theory of time, the Kalam fails, since it assumes real temporal becoming. But A vs. B theory is a purely philosophical question, the physics is consistent with both. On a B theory, it seems you would still have the question, “why does this particular contingent universe (or multiverse) exist tenselessly as opposed to some other universe (or multiverse)?” i.e., the argument from contingency would still need to be addressed.

    Thanks for the exchange–all of the above is subject to correction by the professionals in the combox! :)

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  11. Mason Colbert says:

    Augustine1938,

    Even if an A theory of time were correct, it does not necessarily follow that the Kalam argument is sound. There are proponents of the A-theory of time who do not think the Kalam is a successful argument. For example, both Quentin Smith and Arnold Guminski- who are both atheists, accept the A-theory of time, but do not feel it necessarily wins the Kalam favors. Indeed, Questin Smith has made a collection of cosmological arguments in defense fo atheism.

    http://www.amazon.com/Language-Time-Quentin-Smith/dp/0195155947
    http://infidels.org/library/modern/quentin_smith/self-caused.html
    http://infidels.org/library/modern/arnold_guminski/

    I myself am not entirely familar with the details of the physics/metaphysics of time to make an informed opinion on the matter. I will however disagree that A-series versus a B-series of time are “purely” philosophical. Contributions by Quentin Smith, Craig Callender, Dean Zimmerman, Bradley Monton, etc. have shown that the physics is highly relevant to the debate – given the empirical results of relativity theory, interpretations of quantum mechanics, contemporary quantum gravity theories are highly relevant to this debate.

    Cheers!

  12. Augustine1938 says:

    Mason,

    Yes, I am somewhat familiar with Quentin Smith’s work. I read a debate he had with Dr. Craig a while back (see here http://www.reasonablefaith.org/does-god-exist-the-craig-smith-debate-2003), but as I recall his argument that the universe was “self-caused” didn’t get beyond the “circular causation” problem (which is the incoherence I referred to in my earlier comment about “self-causation”). But he does recognize that the concept of “cause” is applicable to a universe that began to exist.

    Regarding the A-vs. B theory, what I was referring to is my understanding that the A theory is consistent with the Lorentzian version of relativity, and that both theories of time are equally consistent with the empirical evidence–i.e., neither could be experimentally falsified. I’m not familiar with all the literature on this, however. Thanks for the response!

  13. Allan says:

    Augustine1938 “in my view, that is where the physicist has taken the baton as far down the field as he can and hands it off to the philosophers and the theologians, since questions of why the universe began to exist (or, in the case of the eternal cosmologies, why this particular contingent universe exists at all) are beyond the purview of physics qua physics.”. I noticed what you did there. You smuggled in “theologians”. The suggestion that theologians have anything to contribute to our understanding of reality is absurd. Belief in talking donkeys, resurrection, witches, demons, eternal torture chambers etc. does not give any insight into how a universe begins – or not.

  14. Augustine1938 says:

    Allan,

    Well, I’m glad to see at least you did not discard the contribution of philosophers, as some naturalists have done :)

    (Also, I should say I was thinking of those theologians that operate at the nexus of philosophy, science and theology, like John Polkinghorne (http://discovermagazine.com/2011/mar/14-priest-physicist-would-marry-science-religion#.Uw-2_fldUfU) or Greg Boyd (http://reknew.org/2008/01/in-light-of-einsteins-conclusion-that-time-is-relative-how-can-you-believe-that-god-is-not-above-time/)

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  16. Halophilic says:

    Allan,

    “Belief in talking donkeys, resurrection, witches, demons, eternal torture chambers etc. does not give any insight into how a universe begins – or not.”

    Which incidentally is why I’m skeptical that theists have anything useful to add on the topics of morality or the higher hanging fruit Dr. Carroll mentioned during the debate.

  17. I wonder what a Senator would make of this thread and its myriad unreconciled concepts? Physics needs better formalisms, but it will take a long while – paradigms are hard to shift but a new one is needed to reconcile these views respectfully to logic. No one likes the ground shifted from under them, which is why these debates are so inspiring to many – they bring up fundamental shifts in their thinking.

    How to reconcile all thinking? I doubt that’s possible, but I think we can do much better at convincing the public and the semi-informed about the value of physics funding if we have something more … reconciling, as a framework for measurement and for understanding it. It’s people’s inertia at the end of the day – staying loyal and so on. I can only have a bewildered interest in the above until better formalisms are in place.

  18. Jimmy says:

    This was my last concern:

    I found it interesting how Dr. Carroll made the statement that 200+ years ago he may have been a theist, but scientific discovery has since put a stranglehold on any such possibility. This is significant and could not be a more revealing statement in regard to the debate topic. The problem I am having is that this statement requires a significant justification from modern cosmology in order to be meaningful. Think about that statement briefly. If Dr. Carroll could evidence this claim, then any theistic argument from cosmology would be futile. This statement is not a subtle distinction from Dr. Craig’s thesis, it is a 180 degree distinction! The modern cosmological and teleological arguments are using contemporary scientific data by which to increase the probability of their premises being true! For modern cosmology to have completely buried God, so to speak, it seems highly unlikely that any credentialed academic would be making the bold claim that there was data which supported these premises. Lastly, for such a counter claim as Dr. Carroll stated to be true, it seems to me that it should be much more discernible from examining this alleged data that the God hypothesis is unreasonable.
    *Note – I am not claiming either theistic argument uses God as a hypothesis. By using this term, I am simply challenging the idea espoused by Dr. Carroll that contemporary cosmology has basically eliminated such hypothesis. That is a bold statement and was not, in my opinion, any conclusion that could be ascertained from his presentation.

  19. Good video – good debating technique Sean. You had him all the way without your own model. I would have left it to parsimony to refute Craig’s model on the basis that “if” there was something from nothing it was from equal and opposite energy cancellation as a better speculation tied to fact than adding a”cause”, or just choose from the grab bag and say they are all speculative but they have “some” basis in fact rather than merely offending parsimony by being an abstract additive. Methinks you could not resist a little self promotion.

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  21. DEL says:

    I wouldn’t answer for Sean, but if he were I, the reason for converting 160 years ago from theism to atheism would have been Darwinism, not the then clueless, pre-scientific cosmology.

  22. Lucy Harris says:

    Jimmy says:

    For modern cosmology to have completely buried God, so to speak, it seems highly unlikely that any credentialed academic would be making the bold claim that there was data which supported these premises.

    Because there will always be fringe views in any field. As Sean likes to say, almost all cosmologists are atheists.

    And I don’t think Sean would say modern cosmology disproves god, just that it makes god unnecessary as an explanation for the data. Craig is arguing god is necessary to explain it (though he tries to hide from that argument at times).

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  24. SimonW says:

    Well done Sean Carroll, you wiped the floor with WLC and your attitude was spot on throughout, not withstanding the touch of accomodationism at the end.

    I thought you won it immediately by saying that no academic cosmologist believes in the theistic origin of the universe(s). Is that factually true – has there been a survey?

    I can’t see any mention in the comments of what I saw as a massive problem for WLC. During the Q&A at the end, he said that God came into existence at the same time as the creation of our universe. From nothing….? Astonishing!

  25. nick says:

    Sean, I have a math question (by the way, I’ve taken some graduate level differential geometry, but never any GR ):

    As far as I can tell, the BGV theorem says that, assuming the average expansion rate is positive (I don’t know what expansion rate is defined as, but I assume it’s some parameter buried in the metric?), then all geodesics must be past incomplete.

    My question is whether this is equivalent to there being an earliest time. Is is possible that, while all geodesics are incomplete, there is no earliest time? I am picturing (non-rigorously) a kind of ‘infinite pan-flute’ universe, where each pipe of the pan-flute (~geodesic) has a finite length, but the pan-flute extends arbitrarily far down. This is a fuzzy notion, and perhaps this is an annoyingly ill-posed question, but I’m asking it non-the-less.

    Basically, are there geometric/relativistic principles that make ‘past-incompleteness’ of each geodesic equivalent to ‘first moment in time’?

    Thanks!

  26. @Jack Spell – You ask a lot of questions – I’ll try to reply to a few.

    “If so, is it not perfectly legitimate to inquire as to what determines that this particular statically-existing universe obtains, rather than some other one or none at all?”

    Well, for a given model (Hartle-Hawking for example), you could find that the assumptions of the model uniquely determine the conditions of the early universe. That is, the energy density and initial expansion rate are completely explained by the model. If, in addition, those conditions match what we see in our universe, then we have an explanation for why this particular universe exists.

    More likely, the model predicts a range of possible universes. Then we can see if our universe is in the high-probability region or not.

    “Also, would you agree that the A-Theory of time is the much more common sense view?”

    Not if you know something about relativity. In relativity a B theory is a much more natural interpretation.

    “…given the fact that we have *substantial* evidence that our universe satisfies the only condition of BVG — Hav > 0 …”

    This is NOT the only assumption of the BVG theorem. As Sean pointed out several times in his talk, there is another important assumption: that spacetime is a smooth manifold – what Sean called “classical.” We have good reasons to think that on the large scale, our spacetime is smooth and classical. Now, quantum gravity folks don’t agree about much, but they agree about one thing: when we go to sufficiently high energies (equivalently, short length scales) the smooth structure of spacetime will break down. Hence Sean’s comment that singularity theorems like BVG tell us not about what the universe is like, but about where our assumptions probably break down.

  27. Alan Cooper says:

    I think you were right to focus on Craig’s #1 of the Kalam argument because in fact I think *he* is right re #2 – in his claim that modern cosmology (ever since the beginning of GR) does provide a window of opportunity for the idea of a “beginning” of spacetime (and, to be fair to him, that is all he was really claiming – even though his comments often made it look as if he wanted to prove that there really has to be one). Too much energy spent on that issue leaves open the possibility of being confounded in future if it ever turns out that a well-defined best fitting model actually has no meaningful extension beyond a certain point in the past.

    With regard to the fine tuning argument I think you were very effective in pointing out both the “finer-than-necessary” aspect and the difficulties with his attempt to define a probability (especially when we don’t yet have even one provably consistent comprehensive model to put in the space of all “possible universes”).

  28. DanielC says:

    @Jimmy

    What even is the God Hypothesis? There seem to multiple God Hypophesis. Craig’s personal hypothesis seems to be that a disembodied mind exists outside of space and time and this Mind is God. Furthermore God’s “will” is enough to actualise the existence of everything from nothing. This is preposterous, I don’t think it’s even coherent. Even if I grant that a mind can exist without a Brain (which in fact I would highly dispute) to then say this Mind can exist without there being any space to exist in is completely absurd and to then claim that this “transcendent” mind can possess willpower, which I define will as the ability for a mind to actualise it’s desires onto objects which aren’t part of the mind itself (if you’ve got a better definition please share it) and moreover claim that this mind can actualise it’s will without any time existing to pass to allow for thought to turn into desires and desires to be actualised by the will appears to me to be incoherent and utter nonsense.

    I don’t understand how any cosmological evidence could possibly support that hypothesis without first demonstrating that minds can exist without brains. Then furthermore demonstrating that they can exist of time and space which appears prima facie to me to be impossible and is almost certainly beyond anyone’s current capabilities.

    This is an example of where philosophy fails and becomes crackpottery. People start appealing to their intuitions which is pointless since we already know reality can be are counter intuitive and then trying to define things into existence which isn’t just pointless but also obnoxious because much of reality does not submit itself to your, mine or any other person’s definitions.

    One last note: I can’t fathom why so many theists seem to think Craig won because he used to standard cosmology when he clearly relied upon philosophical speculation beyond currently standard cosmology. I’m not sure if this will come as a shock to you but God is not a part of standard cosmology. Neither are “transcendent causes” as Sean has already articulated causes let alone transcendent ones aren’t really a part of modern fundamental physics at all.

  29. Jimmy says:

    Regarding a God hypothesis, as I mentioned, I am not suggesting God as a premise to an argument. Nor would I pretend to represent Dr. Craig’s understanding of this phrase. What I generally understand this to mean would be more relevant to studies of the Historical Resurrection, which posit God as a falsifiable hypothesis to explain data. In this case, its more appropriate to think of [in my opinion] transcendent causes. In other words, simply an explanation that does not, perhaps could not, require a self cause. Thats why I mentioned that any model which posits a self caused universe would have to have some type of consensus within the cosmological community, one would think. I couldn’t image why someone would argue from a model that has less explanatory power than a rival model.

    I could be mistaken, but it seems that your mention of mind and brain is more about issues regarding philosophy of mind, consciousness, etc., rather than a simpler idea of transcendent causes. I recognize where this can get more technical in that sense, when attributes of the cause are explained. That is not what I meant, however.

    As to your mentioning a “Will.” To my mind, a will would be an original phenomenon, rather than a desire or any vehicle for something more primary. My theology may be off here, but it seems to me that when God’s will is spoken of, this means much more than some act of volition. The “Will” of God would be an aspect of his being and essence.

    To your point concerning human intuitions, I would suggest considering the earlier question about “wills” and “minds.” Once again, I realize that details of this argument can get more specific concerning the transcendent cause, but all one needs is a reasonable probability that the cause was not the entity itself (i.e., a self caused universe), for the argument to be successful, in my opinion. So, in summary of the intuition concern, we need not go into our intuitive ideas about consciousness studies to posit a transcendent cause.

    In general, I would agree with you about reality being counterintuitive. It seems very counter intuitive to me that some people engage in metacognition, then deny consciousness by suggesting man to be a bundle of nerves and reflexes. My intuition was surely challenged when I first learned of self directed neuroplasticity, for example, and how mind can enact causal effects upon the physical brain. I would agree that we can’t always go with our intuitions concerning reality.

  30. DanielC says:

    Cosmologists don’t just use Occam’s razor or the apparent eloquence of a Model to evaluate it’s validity, they use empirical evidence and empirical evidence about the universe is still being gathered, Modern Cosmology only really began with the discovery of the Cosmic Microwave Background in 1964, it doesn’t seem to be case of special pleading to merely note Cosmology is still advancing especially when there are good reasons to believe our current models are at least partially inadequate e.g. lack of a complete theory of quantum gravity .

    You say “all one needs for the argument to be successful is a reasonable probability that the cause was not the entity itself” I don’t know how you would gauge that probability, I think all we can really say is that the evidence is currently indecisive on these issues. Although I can’t see the evidence being in favour of God until the God hypothesis becomes coherent and makes some more precise predictions than the universe exists.

    I brought up the philosophy of the mind because William Lane Craig describes God as a transcendent mind and I’ve always assumed Christians assume (do you? I’m willing to be corrected) that God is concious so obviously conciousness is relevant to God. You say “The will of God would be an aspect of his being and essence” I assume you conclude that from Biblical exegesis in which case I would like reference to the biblical passages you are inducing this conclusion from, if you’re using a different method to conclude God’s will is a part of his essence then I would like you to elaborate on the method please (if you have the time of course). However even this claim seem’s incoherent to me. Like you said we could get into more technical arguments but I have no wish to do this because I’m afraid we could end up wasting time engaging in pointless crackpot philosophy.

    You say the God hypothesis is more relevant to studies of the historical resurrection, I assume you’re referencing the (in my opinion) shoddy work done by people like Garry Habermas, Mike Licona and William Lane Craig? If so there’s a few articles I’d like to discuss with you.

    You also say; “It seems very counter intuitive to me that some people engage in metacognition, then deny consciousness by suggesting man to be a bundle of nerves and reflexes.” Firstly I want to be clear I personally do not deny the existence of conciousness, the fact that I am concious is one of the best supported facts I personally know of. Secondly It irks me when people describe the brain as just “a bundle of nerves”, it’s not just a bundle of nerves, it’s a very complicated and important organ. However I agree with you, my suspicion is we do have some real agency, it’s not all just reflexes. Although whether I would characterise that agency as “Free will” I’m not sure but I think this more a matter of rhetorical word games then substantive differences at this point. You ask “how can the mind enact causal effects upon the physical brain?” I will say, I think it’s a valid and important question to ask but unfortunately I don’t think I can currently give you an adequate answer, it doesn’t appear like an unsolvable mystery to me but I think there’s still a lot of work to be done until we have a satisfying answer.

  31. Jimmy says:

    Dan,
    First of all, thanks for the interaction. I certainly have much to learn here, but to engage these significant issues is a step in the right direction.
    A. Cosmic models – my concern here is not whether a particular model is theoretically coherent, but rather how much credibility the model is given within the field. I understand this is how we arrive at superior models, by continuing to theorize and push the envelope, so to speak. I thought it was important at this point in time to recognize, however, that there is a model [as I understand the arguments] which supports some of the premises used in theistic argument. This being the case, I cannot fathom how a physicist could justify the claim that current cosmological science has buried God. Lets consider the implications of what we currently know, but [as you mention] continue searching for what we are yet to discover.
    B. Probabilities: This would relate to my point above in the sense that current data at least supports premises within certain arguments that have theistic implication. Also, I would continue to emphasize the probability that the cause was transcendent, rather then self caused. If there is any reason to believe [it seems this must be the case or no one would be debating this topic] that a self contained model is problematic and an external cause is a real consideration, then why not consider such probabilities? Although I do not pretend to understand quantum theory, my concern pertains to the following: for any entity, whether from below [our minds] or above [the cosmos] there still exists the relation of container and content. Whatever quantum theory may explain, it seems that it would be a feature of content, rather than container. There must be all types of random and counterintuitive aspects to how the cosmic content can be understood. I am not at a point where I can conceive of how a greater understanding of the content (i.e., quantum theory) necessitates naturalistic insight into the container [superstructure] within which all phenomena occurs.
    C. Consciousness relevant to God? Certainly, I was simply focusing on the aspect of transcendent causes. When this can be seriously considered, then other implications make more sense.
    D. To your question of God’s will and my response of essence. I am including a quote taken from “new advent” website which addresses the “divine will” of God:
    The divine will

    Description of the Divine Will

    “(a) The highest perfections of creatures are reducible to functions of intellect and will, and, as these perfections are realized analogically in God, we naturally pass from considering Divine knowledge or intelligence to the study of Divine volition. **The object of intellect as such is the true; the object of will as such, the good. In the case of God it is evident that His own infinite goodness is the primary and necessary object of His will, created goodness being but a secondary and contingent object. This is what the inspired writer means when he says: “The Lord hath made all things for himself” (Proverbs 16:4). The Divine will of course, like the Divine intellect, is really identical with the Divine Essence but according to our finite modes of thought we are obliged to speak of them as if they were distinct and, just as the Divine intellect cannot be dependent on created objects for its knowledge of them, neither can the Divine will be so dependent for its volition. Had no creature ever been created, God would have been the same self-sufficient being that He is, the Divine will as an appetitive faculty being satisfied with the infinite goodness of the Divine Essence itself.** This is what the Vatican Council means by speaking of God as “most happy in and by Himself” — not that He does not truly wish and love the goodness of creatures, which is a participation of His own, but that He has no need of creatures and is in no way dependent on them for His bliss.”
    E. Habermas & Resurrection:
    What I think is significant to this work is that he uses data which is agreed upon by critical scholars of the New Testament, many of which are agnostic or atheist. I won’t go into the minimal facts argument, but I don’t think it’s disputable that he is using data (i.e., historical consensus) by which to support his argument.
    F. The last point on Mind and Brain. I liked most of what you said above and I think a continued investigation into this area may be a great place to be. The research that I am familiar with regarding modern neuroscience makes consciousness a more legitimate topic of discussion, rather than providing any fuel for radical materialists. My point on self directed neuroplasticity was given as an example. A great source for this, if you’re interested, would be work by Dr. Jeffrey Schwartz, research psychiatrist at UCLA. See, “The Mind & the Brain: Neuroplasticity and the power of Mental Force,” as well as, “You are not your Brain,” by the same author. This work provides original research regarding the mind’s ability to enact causal effects on brain as I mentioned earlier.

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  33. Jack Spell says:

    @Robert Oerter

    I appreciate your taking the time to address some of my questions; and I especially thank you for doing so in such a kind, thoughtful manner. I do have some questions (go figure :) ) regarding your replies.

    “Well, for a given model (Hartle-Hawking for example), you could find that the assumptions of the model uniquely determine the conditions of the early universe. That is, the energy density and initial expansion rate are completely explained by the model.”

    I don’t want this to sound disrespectful to you, but I must ask, is that the way you intended to word this paragraph? I ask this because you said that the assumptions of the model uniquely *determine* the conditions of the early universe. How could that even possibly be so? My immediate inclination would be to argue in support of the objectivity of temporal becoming and point out that the conditions of the early universe — regardless of how, who, or what determined them — were in place long before any human being ever existed, much less crafted a cosmogonic model. Nevertheless I would still have an objection even if I were a B-Theorist instead. That is, what causal connection exists so as to permit a state of affairs where a man-made cosmogonic model *determines* what the conditions were like in the universe 13.7 billion years earlier than it?

    The misunderstanding, it seems to me, is that you seem to think that I’m inquiring as to “What determined the current conditions ***that we observe*** in the universe?” To which your answer would be perfectly legitimate and accurate. But that’s *not* the question. What I’m asking is,

    1) If the A-Theory of time is correct, what were the conditions that led to our universe beginning to exist (as a conceptual analysis of “begins to exist”: x begins to exist iff (i) x exists at some time t, (ii) there is no time t* 0 can be continuously defined along some past-directed timelike or null geodesic. . . . In this section we show that the inequalities of Eqs. (4) and (6) can be established in arbitrary cosmological models, ***making no assumptions*** about homogeneity, isotropy, or energy conditions. . . . We assume that a congruence of timelike geodesics (“comoving test particles”) has been defined along O [18], and we will construct a definition for H that depends *only* on the relative motion of the observer and test particles. . . . Again we see that if Hav > 0 along any null or noncomoving timelike geodesic, then the geodesic is necessarily past-incomplete. . . . Our argument shows that null and timelike geodesics are, in general, past-incomplete in inflationary models, whether or not energy conditions hold, provided *only* that the averaged expansion condition Hav > 0 holds along these past-directed geodesics. . . . This is the chief result of our paper. The result ***depends on just one assumption***: the Hubble parameter H has a positive value when averaged over the affine parameter of a past-directed null or noncomoving timelike geodesic.”

    If that weren’t enough, they elaborate further BVG’s implications for other models in higher dimensions, specifically the Ekpyrotic Cyclic model built by Steinhardt and Turok, which is a quantum gravity model!

    “The class of cosmologies satisfying this assumption is not limited to inflating universes. . . . Our argument can be straightforwardly extended to cosmology in higher dimensions. For example, in the model of Ref. [15] brane worlds are created in collisions of bubbles nucleating in an inflating higher- dimensional bulk spacetime. Our analysis implies that the inflating bulk cannot be past-complete. We finally comment on the cyclic universe model [16] in which a bulk of 4 spatial dimensions is sandwiched between two 3-dimensional branes. The effective (3+1)-dimensional geometry describes a periodically expanding and recollapsing universe, with curvature singularities separating each cycle. The internal brane spacetimes, however, are nonsingular, and this is the basis for the claim [16] that the cyclic scenario does not require any initial conditions. We disagree with this claim. In some versions of the cyclic model the brane spacetimes are everywhere expanding, so our theorem immediately implies the existence of a past boundary at which boundary conditions must be imposed. In other versions, there are brief periods of contraction, but the net result of each cycle is an expansion. For null geodesics each cycle is identical to the others, except for the overall normalization of the affine parameter. Thus, as long as Hav > 0 for a null geodesic when averaged over one cycle, then Hav > 0 for any number of cycles, and our theorem would imply that the geodesic is incomplete.”

    Vilenkin reiterates:

    “A remarkable thing about this theorem is its sweeping generality. We made no assumptions about the material content of the universe. We did not even assume that gravity is described by Einstein’s equations. So, if Einstein’s gravity requires some modification, our conclusion will still hold. The only assumption that we made was that the expansion rate of the universe never gets below some nonzero value, no matter how small. This assumption should certainly be satisfied in the inflating false vacuum. The conclusion is that past-eternal inflation without a beginning is impossible.” [Vilenkin, Many Worlds in One, p. 175]

    There are several other papers I could cite that affirm the same conclusion — BVG makes only a single assumption. But this is long enough already.

  34. Jack Spell says:

    That didn’t come out right. What I said was:

    @Robert Oerter

    I appreciate your taking the time to address some of my questions; and I especially thank you for doing so in such a kind, thoughtful manner. I do have some questions (go figure :) ) regarding your replies.

    “Well, for a given model (Hartle-Hawking for example), you could find that the assumptions of the model uniquely determine the conditions of the early universe. That is, the energy density and initial expansion rate are completely explained by the model.”

    I don’t want this to sound disrespectful to you, but I must ask, is that the way you intended to word this paragraph? I ask this because you said that the assumptions of the model uniquely *determine* the conditions of the early universe. How could that even possibly be so? My immediate inclination would be to argue in support of the objectivity of temporal becoming and point out that the conditions of the early universe — regardless of how, who, or what determined them — were in place long before any human being ever existed, much less crafted a cosmogonic model. Nevertheless I would still have an objection even if I were a B-Theorist instead. That is, what causal connection exists so as to permit a state of affairs where a man-made cosmogonic model *determines* what the conditions were like in the universe 13.7 billion years earlier than it?

    The misunderstanding, it seems to me, is that you seem to think that I’m inquiring as to “What determined the current conditions ***that we observe*** in the universe?” To which your answer would be perfectly legitimate and accurate. But that’s *not* the question. What I’m asking is,

    1) If the A-Theory of time is correct, what were the conditions that led to our universe beginning to exist (as a conceptual analysis of “begins to exist”: x begins to exist iff (i) x exists at some time t, (ii) there is no time t* 0 can be continuously defined along some past-directed timelike or null geodesic. . . . In this section we show that the inequalities of Eqs. (4) and (6) can be established in arbitrary cosmological models, ***making no assumptions*** about homogeneity, isotropy, or energy conditions. . . . We assume that a congruence of timelike geodesics (“comoving test particles”) has been defined along O [18], and we will construct a definition for H that depends *only* on the relative motion of the observer and test particles. . . . Again we see that if Hav > 0 along any null or noncomoving timelike geodesic, then the geodesic is necessarily past-incomplete. . . . Our argument shows that null and timelike geodesics are, in general, past-incomplete in inflationary models, whether or not energy conditions hold, provided *only* that the averaged expansion condition Hav > 0 holds along these past-directed geodesics. . . . This is the chief result of our paper. The result ***depends on just one assumption***: the Hubble parameter H has a positive value when averaged over the affine parameter of a past-directed null or noncomoving timelike geodesic.”

    If that weren’t enough, they elaborate further BVG’s implications for other models in higher dimensions, specifically the Ekpyrotic Cyclic model built by Steinhardt and Turok, which is a quantum gravity model!

    “The class of cosmologies satisfying this assumption is not limited to inflating universes. . . . Our argument can be straightforwardly extended to cosmology in higher dimensions. For example, in the model of Ref. [15] brane worlds are created in collisions of bubbles nucleating in an inflating higher- dimensional bulk spacetime. Our analysis implies that the inflating bulk cannot be past-complete. We finally comment on the cyclic universe model [16] in which a bulk of 4 spatial dimensions is sandwiched between two 3-dimensional branes. The effective (3+1)-dimensional geometry describes a periodically expanding and recollapsing universe, with curvature singularities separating each cycle. The internal brane spacetimes, however, are nonsingular, and this is the basis for the claim [16] that the cyclic scenario does not require any initial conditions. We disagree with this claim. In some versions of the cyclic model the brane spacetimes are everywhere expanding, so our theorem immediately implies the existence of a past boundary at which boundary conditions must be imposed. In other versions, there are brief periods of contraction, but the net result of each cycle is an expansion. For null geodesics each cycle is identical to the others, except for the overall normalization of the affine parameter. Thus, as long as Hav > 0 for a null geodesic when averaged over one cycle, then Hav > 0 for any number of cycles, and our theorem would imply that the geodesic is incomplete.”

    Vilenkin reiterates:

    “A remarkable thing about this theorem is its sweeping generality. We made no assumptions about the material content of the universe. We did not even assume that gravity is described by Einstein’s equations. So, if Einstein’s gravity requires some modification, our conclusion will still hold. The only assumption that we made was that the expansion rate of the universe never gets below some nonzero value, no matter how small. This assumption should certainly be satisfied in the inflating false vacuum. The conclusion is that past-eternal inflation without a beginning is impossible.” [Vilenkin, Many Worlds in One, p. 175]

    There are several other papers I could cite that affirm the same conclusion — BVG makes only a single assumption. But this is long enough already.

  35. DEL says:

    Jack Spell:
    Just because Oerter inadvertently wrote “the assumptions of the model uniquely determine the conditions of the early universe” instead of “the assumptions of the model uniquely determine a true statement about the conditions of the early universe” is no reason to pounce on him. I won’t believe you believe he meant what you have insinuated. This attack is either overly pedantic or insufficiently honest.

  36. I just wanted to tell you that it was deeply satisfying that he finally debated a physicist familiar with the theories he tries to reference as arguments.

  37. Tom May says:

    Hi Sean, loved your talk. Apart from the obvious thing of Craig completely misunderstanding the science, I found your remarks about theism being ill defined very interesting.

    Have you read David Deutsch’s book “The Beginning if Infinity”? It covers a lot of ground, but that particular issue is part of it and while he basically argues the same point as you did, he gives it a slightly different spin. There’s also a great TED talk from him about the topic which you might find interesting:
    http://www.ted.com/talks/david_deutsch_a_new_way_to_explain_explanation

  38. Pingback: Links You Might Be Interested In | The Way Forward

  39. Tom says:

    “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.”

    Wow. You really believe this is logical? I know you think the last bit is true (no support) but the logic is on a level with Victor Stenger.

  40. Pingback: In which I take my leave from the new atheism | Choice in Dying

  41. ohi says:

    It is bothersome that people do not accept that time and space are related (space-time) and that there really is 3 dimensions of space and one dimension of time. The universe didn’t “popped” into existence (be/c this implies temporality before the existence of time)- what we really have is the edge of space-time. However, the further advancement of understanding of quantum mechanics will likely make sense of before the big bang theory (i.e. quantum theory of space) and eliminate singularities.

  42. Glen Marquis says:

    Hi Sean,

    Could you let me have anything more about QET you spoke of in the debate, I cannot find anything on the internet, besides a hit back to your page.

    Perhaps, any other past/future theorems!? Thanks in advance.

    Regards,
    Glen.

  43. turner_chris1 says:

    So WLC went first – Again – has he ever gone second? ever?

    Is him going first the only known infinite series of events stretching back into time?

    if a man strikes you on the right cheek……. but if he tries to go first in a debate…

  44. kalam says:

    Hi Sean, thanks for a great debate and for your post debate reflections. It seems to me that, on the one hand (as you admit) we do not have adequate scientific evidence to show that the universe is past eternal or not. On the other hand we have good reasons for thinking that the universe has an ultimate beginning, that the universe could not begin to exist uncaused, and that philosophical reasoning is capable of yielding items of knowledge which we can be even more epistemically certain about than the discoveries of science. Please see the following peer-reviewed materials

    https://www.academia.edu/2154798/Loke_Andrew._2014_._A_MODIFIED_PHILOSOPHICAL_ARGUMENT_FOR_A_BEGINNING_OF_THE_UNIVERSE_._Think_13_pp_71-83._Cambridge_University_Press._doi_10.1017_S147717561300033X

    https://www.academia.edu/1956717/Loke_Andrew._Is_an_uncaused_beginning_of_the_universe_possible_A_response_to_recent_naturalistic_metaphysical_theorizing._Philosophia_Christi_14_2012_373-393

    https://www.academia.edu/6261144/Loke_Andrew_2014_._The_benefits_of_studying_philosophy_for_science_education._Journal_of_the_NUS_Teaching_Academy._National_University_of_Singapore

  45. DEL says:

    kalam:

    The universe, as this blog’s title alludes, may well be preposterous, but its preposterousness is no match to that of your claim:

    “philosophical reasoning is capable of yielding items of knowledge which we can be even more epistemically certain about than the discoveries of science.”

    There may be a philosophical reasoning behind this claim in the links you’ve provided, but if such reasoning is so infallible, how come philosophers have never agreed between them on much? And where, for instance, is Descartes’ epistemology today?

    Moreover, I reason that if a philosopher is really hardly pressed to prove that a basic prerequisite for his personal salvation and afterlife is right there, in the physics, his “philosophical reasoning is capable of yielding” all that is necessary.

    As to the physics, philosophers, even the most prominent ones using their best philosophical reasoning, have a ve…ry long history of getting it wrong. And your own words, quoted above from your own comment, explain this fact perfectly.

  46. Simone says:

    Dr. Carroll,

    about your assertion that Craig took Stephen Hawking out of context when he quoted him to support the idea that the Carroll-Chen model violates the principle of unitarity: why is it that Hawking’s quote is not relevant when discussing yours and Chen’s model? Also, can you please specify what you mean when you say such quote has “nothing to do with cosmology”?

  47. Glen Marquis says:

    1. Lets say we measure caused space-time, we write equations for its behaviour,
    We find experiments that seem to confirm the equations well.

    2. Could Classical or Quantum mechanics describe “a physical cause” for familiar space-time of this pocket-cosmos or Hubble region?

    3. Is it reasonable to expect “space-time” equations to describe its physical causes?
    If that cause is not standard/quantum space-time itself?

  48. Devin Tarr says:

    Dr. Carroll,

    Thank you so much for your participation in this debate. I found your reflections enormously interesting, and soon after went off to read your book “Particle at the End of the Universe”. Also, the physics there was so interesting I began listening to The Teaching Company’s “Great Courses” on physics. I’ve now finished the course on Einsteinian Relativity and the Quantum Revolution, and have started the one on Particle Physics for Non-Physicists. I’m also now pursuing a teaching credential in science because I’ve found modern physics so interesting.

    I ought to write that I’m a sincere believer in God, and that He has revealed Himself to the world through His Son Jesus Christ, but your graciousness, erudition, and winsomeness (I believe) go a long way towards helping us (humanity) in our pursuit of the truth.

    Thank you Dr. Carroll.

    Sincerely,
    Devin Tarr

  49. kalam says:

    DEL,
    Your comments show that you haven’t read the peer-reviewed papers that I linked previously. Those papers demonstrate how philosophy is indeed capable of yielding items of knowledge which we can be even more epistemically certain about than the discoveries of science. Here is the link again:
    https://www.academia.edu/6261144/Loke_Andrew_2014_._The_benefits_of_studying_philosophy_for_science_education._Journal_of_the_NUS_Teaching_Academy._National_University_of_Singapore

    ‘Capable’ does not mean that philosophers always use philosophical reasoning properly, and there are indeed cases where philosophers got it wrong. But the fact that there are cases where philosophers got it wrong does not mean that all are wrong. We have to assess case by case and see how sound the argument is for each case. And the peer-reviewed papers that I linked show that the Kalam is indeed sound.
    https://www.academia.edu/2154798/Loke_Andrew._2014_._A_MODIFIED_PHILOSOPHICAL_ARGUMENT_FOR_A_BEGINNING_OF_THE_UNIVERSE_._Think_13_pp_71-83._Cambridge_University_Press._doi_10.1017_S147717561300033X

    https://www.academia.edu/1956717/Loke_Andrew._Is_an_uncaused_beginning_of_the_universe_possible_A_response_to_recent_naturalistic_metaphysical_theorizing._Philosophia_Christi_14_2012_373-393

    On disagreements among philosophers read Anthony Flew’s remarks:
    ‘The attempt to show that there is no philosophical knowledge by simply urging that there is always someone who can be relied on to remain unconvinced is a com¬mon fallacy made even by a distinguished philosopher like Bertrand Russell. I called it the But-there-is-always-some-one-who-will-never-agree Diversion. Then there is the charge that in philosophy it is never possible to prove to someone that you are right and he or she is wrong. But the missing piece in this argument is the distinction between producing a proof and persuading a person. A person can be persuaded by an abominable argument and remain unconvinced by one that ought to be accepted.’ Anthony Flew, There is a God, 40-41