Debating William Lane Craig

By Sean Carroll | April 5, 2011 9:23 am

William Lane Craig is a philosopher and theologian, most famous for advocating the Kalam cosmological argument for the existence of God. As far as I can tell, he is fairly well-respected in the theology community; I cited him among other people in my recent paper. He’s also a frequent participants in debates against atheists. These are slightly weird events; everyone says they’re a terrible idea, but everyone seems to willingly participate in them. Personally I think they can be a very useful forum, if done well.

Craig recently debated Lawrence Krauss in an event that got a lot of publicity. You can read Craig’s post-mortem reflections here; in response, Krauss has offered his own thoughts on how things went down, which are posted at Pharyngula. You can watch the whole thing on YouTube, but be warned it’s a long multi-part extravaganza.

As to who won, it’s a mixed bag. Craig is a very polished debater, and has his pitch honed to a fine sheen; every sentence makes a succinct point. On the other hand, many of his sentences are simply false. For example, he argues that the universe can’t be eternal, because infinity is an self-contradictory notion, because “infinity minus infinity” has no correct answer. This is not an unfair paraphrase.

In response, Lawrence was game, but much more impressionistic, with a style more appropriate to a public talk than to a formal debate. It depends on what you’re looking for, of course; he did have the advantage of being right. Craig is sufficiently good at debating that atheists are now advising each other to stay away from him for fear of looking bad — e.g. here and here. I sympathize with the general message — don’t get into something like this unless you know what’s coming and are truly prepared — but not with the final impression, that atheists should just steer clear. We should be good at presenting our arguments, and ready to do so. Craig is wrong about many things, but he’s not an out-and-out crackpot like Hugh Ross or Ken Ham. A good debate could be very interesting and helpful to thoughtful people who haven’t yet made up their minds. Being correct is already a huge advantage; we should be able to make our side clear using the force of reason, like we’re always telling people we do.

CATEGORIZED UNDER: Religion
  • Aloysius

    Given that much of what Craig says is simply false, and he refuses to acknowledge that or correct himself despite being called out on it numerous times, in what sense is Craig not a crackpot? He isn’t intellectually honest or a debater in good faith. What is to be gained by engaging him as a serious figure when he just makes stuff up? How could one ever possibly “win” a debate against someone like that? It doesn’t matter how clear and reasonable you are when Craig will simply dismiss anything, anything you can possibly say with more of his made-up nonsense.

  • ChuckWhite

    Sean, I usually agree with you (where I have knowledge to judge). I disagree that there is an argument to be made for or against atheism on any basis that depends on right versus wrong arguments (belief versus dis-belief).

    As an agnostic, I am simply boggled by statements claiming “proof” of the (non)existence of a deity. I admit to being personally skeptical of such a deity, but, it cannot be proven nor dis-proven.

    This debate proved one thing to me. Proofs, one way or another, do not exist. Argument on such a subject is as irrelevant as discussing the number of angels which can exist on the head of pin. They can only serve the purpose of swaying others opinion, which, in my opinion is a waste of time in discussions of belief.

  • Dave Roberts

    Not trying to be mean here but only one word fits. Never argue with an idiot. He’ll drag you down to his level and then beat you with experience. An idiot can be defined as a mentally deficient person, or someone who acts in a self-defeating or significantly counterproductive way. I’m using the “significantly counterproductive way” portion of the definition.

  • Chris Harris

    Mr. Carroll

    1) Have you addressed the physics claims he and other apologists have made on here? (I.e. fine tuning, Kalam…) While I think that Krauss did an excellent job pointing out the flaws, and I think Vic Stenger did a fairly good job at it as well in their debate, I’d love to read another view on it.

    2) Would you personally ever do a debate with Craig?

    Thanks for your time.

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Chuck– I don’t think anyone talked about “proofs,” so I’m not sure what you are arguing against. Science doesn’t prove things, but it does draw conclusions.

    Chris– Yes, I addressed those in my recent paper, albeit under the constraints of a Draconian word count limit. I would debate any non-crackpot if the conditions were right, but the conditions would have to be right.

  • vel

    I wish someone would simply ask Craig, when he claims that JC was resurrected, “so, dear, which tomb is the “real” one? and please do support your claims with evidence.” funny how Christians forgot to mark this most important site in Christendom.

  • http://letterstonature.wordpress.com/ Luke Barnes

    “he argues that the universe can’t be eternal, because infinity is an self-contradictory notion, because “infinity minus infinity” has no correct answer. This is not an unfair paraphrase.”
    Yes, it is. For the record, Craig’s argument is as follows. He has no problem with actual infinities in mathematics. But note what we must do to avoid contradiction. (Infinity – infinity) cannot be uniquely defined on the extended real line without contradiction. We must impose the restriction that (infinity – infinity) is not allowed. Now, what if an actual infinity existed in reality? We would not be able to impose the restrictions needed to avoid contradiction. We conclude that realised actual infinities are not possible. A similar conclusion is reached by George Ellis, here: http://adsabs.harvard.edu/abs/2009GReGr..41.1475E

    This is one of the reasons that Craig keeps “winning” – his opponents don’t take the time to actually learn and critique his arguments, making it easy for Craig to point out the straw men.

    Incidentally, Sean, could you comment on Krauss’ assertion that inflation explains the low entropy of the universe?

  • GManNickG

    Chuck, can you prove there are no coins in your pocket? Of course you can: reach in and see.

    As soon as you stop wasting your time thinking in absolutes (an activity every sensible person understands is meaningless; no, you can’t prove absolutes; move on), you can use the more pragmatic form of “proof”.

    Non-existence is proved by the failed verifications of tests, and the strength of that evidence is directly proportional to the certainty of your test. That’s why reaching into your pocket and finding no coins is pretty strong evidence there are no coins; strong enough you can consider it proof.

    Likewise, spending thousands of years looking for evidence (via increasingly powerful observation tools) to support claims that a multi-self-refuting God exists (that are explainable in much less miraculous terms, like being primitive philosophy and politics, sustained by the indoctrination of children), and finding nothing is strong evidence against the existence of such a God.

    No, there is no way to test for a simplistic deity, but this only leaves you as an unbeliever. For all other cases where the deity supposedly influences our world: they have failed the tests.

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Luke– No, it is not. Did you listen to the debate? My paraphrase was almost identical to what Craig actually said. Sure, he might have more verbiage behind it, ready to dredge up in the rebuttal when he was challenged, but that doesn’t change what he said in his first speech. The verbiage you suggest, of course, doesn’t make any more sense than my original paraphrase. We don’t “impose the restriction that infinity minus infinity is not allowed”; we simply treat infinity as it is properly defined, which is different from the definition of some finite number.

    Ellis and Stoeger’s conclusion is not even remotely similar, but it’s a good example of Craig distorting the results of respectable cosmologists to his ends. They urge caution when dealing with infinity, but state explicitly that infinities are possible — their point is simply that it takes an infinite amount of time to make an infinite number of galaxies in a finite space. This propensity to misrepresentation might have something to do with Craig’s “winning.”

    Krauss’s assertion about entropy is not correct, as far as I understand it. (It is closer to being correct than what Craig said about entropy, which is just word salad.) Many cosmologists say incorrect things about entropy, but some of us are trying hard to set things straight.

  • http://www.damtp.cam.ac.uk/people/e.lim/ Eugene

    heh, “If you can’t dazzle them with brilliance, baffle them with bullshit” (W.C. Fields) seems to be the key in winning debates.

  • http://letterstonature.wordpress.com/ Luke Barnes

    Ellis and Stoeger: (Quoting Hilbert:) “Our principal result is that the infinite is nowhere to be found in reality. It neither exists in nature nor provides a legitimate basis for rational thought . . . The role that remains for the infinite to play is solely that of an idea”. *Our results concur with this judgement.*

    I believe Craig said the same thing: “this shows that infinity is just an idea in your mind, not something that can exist in the real world.” Something like that. I might have misunderstood Craig.

    From “Elements of real analysis By David A. Sprecher”: “while alleviating one problem, the new symbols [infinity and - infinity, to make the extended reals] create other enigmas … no meaning is given in the system to infinity + (- infinity).”
    This is Craig’s point. If there were actualised infinities, then we could perform real tasks whose result was infinity – infinity. Reality would not be able to leave infinity – infinity undefined.

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Ellis and Stoeger, actual words, not quoting anybody: “the real situation is that physical processes may be such that eventually an infinite number of galaxies, stars, planets, and civilizations will tend to come into existence; but that state is not achieved at any finite time through the supposed physical processes.”

    I’m not sure why you’re so interested in defending Craig on this issue. You can’t deduce that the universe must have a beginning simply by pure reason; it’s very easy to make models that are eternal. None of the cosmologists Craig refers to actually believe his conclusion that the universe must be finite; they are all willing to contemplate universes that last infinitely long into the future.

  • http://thecosmist.com The Cosmist

    Does anyone ever discuss Godel’s incompleteness theorem in these theological debates? It seems to me this could be the best point theists have in their favor — if there are things which are true but can never be proven, isn’t that in a sense a logical justification for religious faith and a fatal blow to scientific rationalism?

  • http://letterstonature.wordpress.com/ Luke Barnes

    Your quote from Ellis and Stoeger proves my point. There is no actual infinity, only a potential one. There is no time when there are an infinite number of galaxies. The number of galaxies can be made merely arbitrarily large. Infinity acts as a limit: sideways eight, not aleph_null. Craig has no problem with universes that last infinitely long into the future for the same reason. Potential infinities are actually finite.

    My bigger point is that, if you’re not careful, you’ll end up attacking a straw man rather than Craig’s arguments. Showing that infinity is not a contradictory concept in mathematics will get you nowhere. I think that the best reply to Craig’s argument is that he has not demonstrated a contradiction if an actual infinity were to exist – he has only shown that we must be careful. Take an infinite library. Remove all the odd numbered books – an infinite number remain. Remove all the books numbered greater than three – three books remain. There is no contradiction, just the need to be more specific when you say “now remove an infinite number of books.”

  • Mike

    Sean,

    You say “[a] good debate could be very interesting and helpful to thoughtful people who haven’t yet made up their minds. Being correct is already a huge advantage; we should be able to make our side clear using the force of reason, like we’re always telling people we do.”

    I have sympathy for this view, since I always try to be eminently reasonable :)

    However, Krauss has an interesting take away from the debate. He says “I believe that if I erred at all, it was in an effort to consider the sensibilities of the 1200 smiling young faces in the audience, who earnestly came out, mostly to hear Craig, and to whom I decided to show undue respect. As I stressed at the time, I did not come to debate the existence of God, but rather to debate about evidence for the existence of God. I also wanted to demonstrate the need for nuance, to explain how these issues are far more complex than Craig, in his simplistic view of the world, makes them out to be. For this reason, as I figured I would change few minds I decided also to try and illustrate for these young minds the nature of science, with the hope that what they saw might cause them to think. Unfortunately any effort I made to show nuance and actually explain facts was systematically distorted in Craig’s continual effort to demonstrate how high school syllogisms apparently demonstrated definitive evidence for God.”

    I know you have your differences with the take-no-prisoners approach of Sam Harris and others, but it seems to me that it does little or no good (in most situations) to beat around the bush rather than clearly and bluntly, as Krauss says he should have done, confronting “with the gloves off, . . . the disingenuous distortions, simplifications, and outright lies . . .”

    These distortions, simplifications and outright lies rest at the core of every theist argument. You’re just too nice a guy sometimes. :)

  • Simon

    I’ve not watched the debate so might be missing the point. But —

    I think the best way to disarm the “argument to design” (of which the fine-tuning argument is a modern version) and the “cosmological argument” and variants requires more skill with philosphy than science. (J. Mackie did a good job 30 years ago in his classic book “The Miracle of Thesim”). And Simon Blackburn’s made the point many times. Hume said it oh so well back in 1776 but most people still seem to miss the point…

    Basically, any “argument to design” is an argument by analogy, using the “concious human designer -> designed product” model as a model for the whole cosmos. Without too much thought you can see this is a terrible argument: the stronger the similarity in effects, the more plausible is a strong similarity of causes – but here we have massively different effects (human products vs. entire cosmos). At this point it’s tempting to conclude the cosmos requires a creator much “greater” than humans – but that is not the correct deduction. All we can say is that if there is such a creator, this argument can say nothing about it, only that it is likely different from human conciousness. Now, we do have an example of such a thing: evolution by nature selection can produce amazing ‘designoid’ objects and is completely different from a concious creator. But you don’t even need to know of an alternative such as natural evolution. The argument simply doesn’t take you any closer to ‘god’ than you started. No need to go through the physics, just look at the structure of the argument. As Blackburn says, even if you accept the argument (paraphrasing) “you can’t check out of Hotel Supernatural with more baggage than you took in.”

    Similar issues apply with the cosmological arguments.

  • Koray

    Goedel’s incompleteness theorem(s) are not a fatal blow to scientific rationalism. The fact that there are truths in Peano arithmetic that have no proofs does not mean that any arbitrary statement of arithmetic for which we don’t seem to have a proof at the time is true. It can also be false, or we can find a proof that shows whether it’s true or false.

    Anybody who makes arguments about the physical universe entirely based on logic (e.g. via invoking axioms of ZF set theory, real numbers, infinities, etc.) does not know what mathematical logic studies and how it operates. It’s especially bad if that person is a “philosopher”. The same goes for any interpretation of probability and use of statistical inference methods (e.g. Bayesian).

  • KWK

    Sean,

    You said:
    “You can’t deduce that the universe must have a beginning simply by pure reason; it’s very easy to make models that are eternal. None of the cosmologists Craig refers to actually believe his conclusion that the universe must be finite; they are all willing to contemplate universes that last infinitely long into the future.”

    I think you’re missing a very straightforward point: while time can go on indefinitely into the future, any future event will be a finite time from Now. But if time truly extends infinitely into the past, then it would be impossible to arrive at the time we call Now, since no matter how much time had passed, Now is still an infinite amount of time away from whatever point had previously been reached.

    So that part of the Craig’s arguments seems sound, even if other aspects of them seem premature at best, if not entirely misplaced–e.g, arguing from the Big Bang to a Big Banger seems to me to be a problem, since the Big Bang also leads to actual infinities if you naively run the math backwards. That’s probably why we’ll need Quantum Gravity to fix things–and who’s to say that such a solution will leave the all-important temporal “beginning” intact? So at best one could say that current observational evidence appears to support this aspect of Craig’s position; but I rarely hear such caveats when this argument is actually put forth.

    On a related note, early Christians seemed to have no problem with fitting their beliefs in an all-powerful Creator God into the reigning Greco-Roman cosmology of the time, which assumed a universe of infinite extent. Now they may have just missed the contradiction for several centuries (and the Jews must have missed it for even longer), but it was not until quite a bit later that Christians decided their universe needed to be finite. So while theists (and everybody else) are on solid ground when arguing for a finite past from logical, philosophical, or even observational grounds (provisionally), it certainly need not play such a central role in theists’ worldviews as it actually does.

  • Coherent Sheaf

    `KWK,

    You said:
    “I think you’re missing a very straightforward point: while time can go on indefinitely into the future, any future event will be a finite time from Now. But if time truly extends infinitely into the past, then it would be impossible to arrive at the time we call Now, since no matter how much time had passed, Now is still an infinite amount of time away from whatever point had previously been reached.”

    Whenever I hear this argument I ask myself: Reached from where? If the universe extends infinetely in the past, nevertheless every point in the past has only a finite distance to us.
    If you postulate a point at -infinity, you postulate the existence of a beginning the very claim that is in dispute.

  • Phil

    I think there is a serious contradiction in WLC’s argument.
    He claims there are no actual infinities

    yet he claims there has to be a singularity implying a beginning of time. Craig’s own words in Cosmos and the Creator:
    “When the expansion is coupled with the 1968 Hawking-Penrose singularity theorems, it leads, via a time-reversed extrapolation, to a universe which began at a point in the finite past, before which it literally did not exist.
    That initial event has come to be known as the “Big Bang.” This cosmological singularity, from which the universe sprang, marked the beginning, not only of all matter and energy in the universe, but of physical space and time themselves. ”

    Since singularities contain infinities,, heres Alan Guth’s definition of a singularity:
    “an infinite density, infinite pressure and infinite temperature… the singularity is sometimes said to mark the beginning of time , but it is more realistic to recognise that an extrapolation to infinite density cannot be trusted.” (The Inflationary Universe)

    Craig’s argument seems to me to then be a contradiction. he denies infinities when it suits him :eternal past yet embraces them when they suit him : singularities.

    Furthermore in Guths 2007 review of eternal inflation on page 16
    “Aguirre and [49, 50] have proposed a model that evades our theorem, in which the
    arrow of time reverses at the t = −∞ hypersurface, so the universe “expands” in both
    halves of the full de Sitter space. ”
    WLC conveniently ignores this.

  • Brian Mingus

    I think Sean should debate him!

  • KWK

    @CoherentSheaf:
    While any event we care to specify may be a finite interval from Now, that event still requires an infinite progression of events prior to it. As I see it, I’m accepting the premise of an infinite past for the sake of argument, and then showing how it leads to a logical impossibility (traversing an infinite interval), thus showing that the premise cannot possibly be true. That’s not the same as smuggling the concept of a beginning into my infinity.
    @Phil:
    I’m not sure if Craig has actually argued anything like this, but…if the Planck length is the “minimum meaningful size”, then cramming the entire universe inside a sphere of that size makes the density, pressure, etc. very very large, but not truly infinite. Of course, that still ignores the fact that quantum effects become relevant long before we reach the Planck scale (so we really have no business blithely extrapolating down that far), but that is one potential way to avoid a physically-realized actual infinity.
    I can’t have been the first one to think of this, so if someone already knows what works (or doesn’t work) with this proposal, I’d love to hear it.

  • http://golem.ph.utexas.edu/~distler/blog/ Jacques Distler

    From “Elements of real analysis By David A. Sprecher”: “while alleviating one problem, the new symbols [infinity and - infinity, to make the extended reals] create other enigmas … no meaning is given in the system to infinity + (- infinity).”
    This is Craig’s point. If there were actualised infinities, then we could perform real tasks whose result was infinity – infinity. Reality would not be able to leave infinity – infinity undefined.

    If that’s his point, then he is stupider than I thought. “0″ is certainly realized in nature, and 0/0 is every bit as ill-defined as ∞ − ∞, and for exactly the same reason.

  • whoschad

    I didn’t listen to the debate, but I did see that the audience voted at the end and William Lane Craig was the winner. Does that change anything, or not really?

    Another question for all the posters above. Are you saying that the universe is actually infinite, or are you just saying that Craig’s argument is wrong? I have no problem with Craig being wrong, I’m just wondering why the universe must be infinite.

  • Kevin

    I don’t think these religious-atheist debates are useful, and I say that as a vocal atheist. They take the matter at hand, which is an objective truth claim (“God exists”), and effectively turn it into a political issue. Public, person-vs.-person debates generally are not won or lost on the merits of the arguments, but on style and rhetoric. A claim supposedly based in logic, mathematics, and/or empirical evidence (as Craig claims his argument to be) should be evaluated the way we evaluate any other such claim: via peer-reviewed papers and other such publications that reduce the confounding factors which dominate public debates.

    Grossman’s Law states “Complex problems have simple, easy to understand wrong answers.” Craig relies on this principle to mislead people by saying things that seem true, based on imperfect human intuition and cognitive biases. By giving him a forum in which to do so, we only end up further confusing the fundamental question, which is not an issue of personality but an issue of facts (or lack thereof). Getting out the information about atheism and theism is a good thing, and we should do it as much as possible; but these public performances end up being little more than dog-and-pony shows, spreading misinformation with a net benefit for the opposition.

  • http://golem.ph.utexas.edu/~distler/blog/ Jacques Distler

    Another question for all the posters above. Are you saying that the universe is actually infinite, or are you just saying that Craig’s argument is wrong? I have no problem with Craig being wrong, I’m just wondering why the universe must be infinite.

    The universe is, as far as we can tell, spatially infinite. (If it’s spatially-finite, then its “size” is larger than we can see.)

    It will also endure infinitely in the future (will not recollapse).

    So, I guess your question is about whether it extends infinitely into the past. The answer is “Possibly yes, possibly no, but it is way beyond our current abilities to definitively decide that question.”

    But that is a scientific question, not something decidable by the application of childish syllogisms.

  • paulbk

    A debate about whether there is sufficient evidence for the existence of god is worse than useless unless both sides first agree on “what is a god?”

    If one party says ‘god’ is the creator of the universe. Fine. Then by that definition there is a god since there is a universe. However, if they go on to say that god not only created the universe but also selectively intervenes to change the course of events in ways contrary to the laws of physics, then they have a problem with their neural network. In other words, they claim that god can perform miracles. Like changing the path of a giant meteor such that it won’t smush the Vatican. There is no evidence for miracles. None.

    There are many things we still don’t understand completely or can’t prove in exhaustive detail. But there is no evidence for miracles as I define it in the example above. A miracle is not simply an improbable event. Physics allows improbable events. A miracle is an impossible event, i.e., an event not allowed by current law. Like me putting your head in my tub and your torso in the trunk of my car. And three days later I meet you at church bingo! That is a miracle because it defies all current law.

    Now if they claim there is a god but “he/she/it” does not intervene in the day to day affairs of the world, then I counter: What is the difference between a god that does not intervene and no god?

  • Pseudonym

    Whether or not Craig is well-respected in “the theology community” largely depends on what you mean by “the theology community”. If you mean “the US evangelical protestant theology community”, then perhaps.

    I’ve never met a mainline protestant theologian outside the US who think he’s worth a mention. I used to hang around (and talk a lot with) many theologians, and I’d never heard of him until I started reading atheist blogs. These aren’t ultra-liberals, either; we’re talking about people who think Jurgen Moltmann and Wolfhart Pannenberg are brilliant. But if Craig warrants a thought, they seem to think that he’s to theology what Ayn Rand is to philosophy.

    Oh, and that’s just the Protestants. Eastern Orthodox and Roman Catholic theologians are usually even more dismissive, if they’ve heard of him at all.

  • randommuser

    @whoschad

    In the most well-established model today, the Big Bang theory, the universe is finite in both time and space, but it is less clear whether it will last infinitely into the future. So I think the point here is mostly to show that Craig’s argument is wrong.

    @KWK

    It may be helpful to state exactly what your argument is. I will paraphrase it to the best of my understanding, please point out if this is not what you meant. Even in an infinite universe, there is still a finite amount of time between any two fixed events. So to say there is infinite time before an event, you need to go back to a “beginning” of the universe, which doesn’t exist (this is the whole point of assuming the universe being infinite in time).

    So the statement you are claiming is probably:
    If in a hypothetical universe, there is an event B such that for any length T of time interval, there exists an event A such that the time interval between A and B is greater than T (that is, there exists events arbitrarily far in the past), then such an universe is logically inconsistent.

    However, that statement is clearly false. When Sean said that it is easy to construct a consistent universe with infinite time, I suppose he has something like this in mind: consider an universe with three dimensional Euclidean space. There is a set (can be either finite or infinite) of “particles” having certain positions and velocities at time t=0. They move linearly at constant speed at all times, so their location at all times are determined. This, then, gives a hypothetical universe, clearly consistent since it is based on a simple mathematical model.

    Granted, this is not a very interesting universe, certainly very unlike ours. However, we should be able to construct more complicated models, while preserving the property of lasting infinitely in time. If your argument is to work, you need to establish something like:

    If a hypothetical universe is “interesting” / “similar to ours”, and has the property given above, then it is logically inconsistent.

    First, you need to define “interesting” or “similar to ours”, then use this condition to show an inconsistency. You have to use some condition since you don’t want your argument to work on the simple universes constructed above.

    @Kevin and others

    I have to agree that live debates are not very useful in showing relative strength of arguments, since a lot depends on the skill of debaters. This is especially important here since most of the debaters on the atheists side have professions very different from debating. I think doing debates in writing, giving everyone ample amount of time to think, would be much more useful. Unfortunately it will also have very limited effect considering that an average people today isn’t going to spend hours reading philosophical arguments :)

  • Doug

    @KWK:
    No, you haven’t demonstrated any logical impossibility, you’ve merely re(/mis)stated the premise and called it logically impossible. There is no “traversing” being done – the universe includes time in it. To say the universe goes back infinitely far back in time is exactly like saying it can extend infinitely in spatial directions – would you argue that spatial infinity is impossible because nothing can “traverse” an infinite distance (in a finite time, at least). Never mind that for photons exactly zero time has passed since the Big Bang (or any event).

    Also, if there isn’t a true infinity at the Big Bang singularity, then there isn’t a true origin of time either.

  • Thomas

    The full debate is uploaded here; http://www.youtube.com/view_play_list?p=F07912BD59617C72

    Introduction start in part 2, 2:12 seconds into the video.

  • Coherent Sheaf

    KWK,

    Could you please define exactly, what you mean by `traversing`. The term confuses me.

  • Phil

    Surely the thing to do is to GET ALAN GUTH OR ALEX VILENKIN TO DEBATE WLC.I havent read anythting by Borde but I am confident neither of these two (that WLC quotes again and again again) agree with WLC having read their books. Vilenkin is very explicit that their therom does not support the case for theism yet WLC conveniently ignores this quote.
    @KWK
    YEs if you quantize space time then you can avoid infinities but the conseqwuence of that can be avoiding a begining of time:
    for example see Abhay Ashtekar:
    http://iopscience.iop.org/1742-6596/189/1/012003/pdf/1742-6596_189_1_012003.pdf
    “However, because gravity is geometry in general relativity, when the gravitational field becomes singular, the continuum tares and the space-time itself ends. There is no more an arena for other fields to live in. All of physics, as we know it, comes to an abrupt halt…When faced with deep quandaries, one has to carefully analyze the reasoning that led to the impasse. Typically the reasoning is flawed, possibly for subtle reasons. In the present case the culprit is the premise that general relativity —with its representation of space-time as a smooth continuum— provides an accurate description of Nature arbitrarily close to the singularity…The situation is very different with quantum evolution. As the density and curvature enter the Planck scale quantum geometry effects become dominant creating an effective repulsive force which rises very quickly, overwhelms the classical gravitational attraction, and causes a bounce thereby resolving the the big bang singularity.”

    So a qauntized solution may remove the infinites at the classical singualrity but it can also remove the begnining of time in the process.

    Thast why I think WLC argument is a contradiction. If you want to keep a classical picture, yes you get a beginnning of time , but you also get a bunch of infnite vlaues = something WLC insists is impossible. If you use a quantum approach you may get rid of the infnities but then the beginning of time looks a lot more doubtful.

  • bad Jim

    I have to pile on. Zeno’s paradoxes are precisely on point. The prospect of infinity is present in any interval, no matter how small. There is a one to one relationship between a single step and an infinite distance, and between a second and eternity.

    Taking a step refutes Zeno, because the infinite sequence of intervening points is not an incomprehensible horror but a necessary consequence of treating the process arithmetically.

  • slw

    A debate doesn’t figure out who is right and who is wrong, it simply finds out who is the better debater.

    It’s fun, sometimes insightful, but epistemologically useless.

  • http://www.astro.multivax.de:8000/helbig/helbig.html Phillip Helbig

    “Does anyone ever discuss Godel’s incompleteness theorem in these theological debates? It seems to me this could be the best point theists have in their favor — if there are things which are true but can never be proven, isn’t that in a sense a logical justification for religious faith and a fatal blow to scientific rationalism?”

    Just because there are some things which are true but cannot be proven to be true doesn’t mean that an arbitrary claim without proof is true.

    A serious question: Gödel’s theorem relies on constructing something like “a consistent system will not be able to prove that this statement is true”. Are there any other “obviously true” statements which cannot be proven which don’t rely on this special construction?

    Gödel’s theorem gets a lot of press mainly because people think it gives them some sort of superiority: they can see that the statement is true, even if a powerful computer can’t, and believe that this makes them superior to a machine. But what is the difference between this and “Roger Penrose will never have the thought that this statement is true, although I can”? Does this make me a better thinker than Roger Penrose? (I use “never have the thought” to avoid the red herring that Roger can glimpse the truth but doesn’t want to utter it etc. Also, if we base our judgment of machines on what they display, but of people on what they think, then there is the danger of assuming that that which we wish to prove (machines can’t really think) is true.)

  • Matt

    “For example, he argues that the universe can’t be eternal, because infinity is an self-contradictory notion”

    1. Dr. Craig’s point was that quantitative infinites exist as an idea–but that it’s implausible that they exist in the actual world. For example, what or who would stop somebody from taking or adding coins to an infinite number of coins; and if you’re allowed to add coins to an infinite number of coins, then wouldn’t that prove that there wasn’t already an infinite number of coins? For a better example of the logical incoherence of actual quantitative infinites, please see Hilbert’s paradox of the Grand Hotel.

    2. There’s also no empirical evidence for the existence of actual quantitative infinites.

    3. As for the universe itself, current scientific evidence seems to suggest that the universe is past-finite and not past-infinite. Feel free to correct me if I’m wrong.

    Regardless, given your responses, I can see why you wouldn’t want to debate Dr. Craig.

  • Coherent Sheaf

    Matt,

    I don`t think that actual infinities are logically incoherent. The problem you suspect exists comes from a confusion about the nature of subtraction. If we remove all even numbered people from the hotel, we simply have removed infinitely many people, and since we have removed a specified set, we know that there are infinitely many left. However if we don`t specify which infinite set we remove we do not know how many people are left. These are the facts about the matter.
    Now you seem to interpret this in the following way:
    A: If I remove a subset U from a set X this corresponds to an arithmetic operation, such that the cardinality of the new set X-U is wholly determined by the cardinality of U and X.
    B:If U and X are infinite, A is not the case. Hence X must be finite.

    However people who use this line of reasoning, give no justification for A. So all that Hilberts Hotel proves, is that if actual infinites exist, A is not the case.

  • SLC

    Perhaps Prof. Krauss should have followed the late Stephen Jay Goulds’ advice to Richard Dawkins then the latter asked for his advice relative to debating creationists. Goulds’ response was, “Don’t do it!” The reason is that creationists engage in what is known as the Gish gallop. However, if scientists like Prof. Krauss insist on engaging in such activities anyway, he should consider the example of Brown biology professor Ken Miller when he was inveigled by his students into debating creationist Henry Morris.

    Prof. Miller prepared for the debate by reading everything he could find that Miller had ever written and studying any videos of previous presentations by Miller that he could find on the subject of evolution. In this way, he knew exactly what Miller was going to say and he was able to prepare cogent talking points to refute the latter. In this way, he was fully prepared to counter the Gish gallop with a Miller gallop of his own, refuting anything that Miller would say. This is what Prof. Krauss should have done prior to engaging in a debate with Mr. Craig. His failure to do so allowed Mr. Craig to successfully engage in a Gish gallop. I would respectfully suggest to Prof. Krauss or anyone else who is tempted to debate creationists that they either follow Goulds’ advice or Millers’ example.

    Re Matt @ #37

    Here’s an example of the notion infinity – infinity making physical sense. In quantum electrodynamics, when computing the anomalous magnetic moment of the electron, mu, one is faced with divergent integral expressions. In particular, the expression I – m, where I is a logarithmically divergent integral expression and m is the mass of the electron, occurs. This is resolved by redefining m as m(0), the “bare” mass of the electron, setting it equal to infinity and setting the resulting expression I – m(0) equal to -m. This, of course, is mathematically preposterous; however, this procedure results in a computation that agrees with the observed value of mu to 10 significant digits, rather better than the estimate for pi given by scriptures which is accurate to 1 significant digit.

  • http://somewhatabnormal.blogspot.com/ Robert Oerter

    I’m amazed that Craig is still making that stupid infinity minus infinity argument. I’m also amazed that no one ever calls him on an outright lie: that “mathematicians agree” there can be no actual infinity. The truth is almost the exact opposite: mathematicians agree there is no LOGICAL problem with infinities. Hilbert’s hotel situations are counterintuitive, but they are NOT contradictory, so they don’t disprove anything.

  • athanasius

    Correct me if I’m wrong, but it appears the Carroll/Barnes exchange above in the comments to this blog has established that (1) Dr. Krauss was wrong in his debate with Craig regarding inflation explaining the low-entropy of the universe and (2) that both Dr. Krauss and Dr. Carroll were wrong and Dr. Craig was right that while events can be potentially infinite into the future, an actual number of events cannot be infinite into the past (because of the Hilbert’s Hotel effect–see http://www.woodford.redbridge.sch.uk/rs/year10-11/hilberthotel.html). That is quite remarkable, but demonstrates the value of blog comments.

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    You’re wrong. The Hilbert Hotel says nothing at all about whether events can be infinite toward the past. This is not something considered controversial among sensible people.

  • athanasius

    Sean: “You’re wrong. The Hilbert Hotel says nothing at all about whether events can be infinite toward the past. This is not something considered controversial among sensible people.”

    Well, it has been a major point of controversy in the philosophical literature over the last 30 years (see sources gathered here: http://commonsenseatheism.com/?p=1637 Major figures in the field–theist and atheist–such as Sobel, Oppy, Morriston, Quentin Smith, etc. have grappled with it). But I suppose if you believe that all of those who have contributed to the literature of that controversy are “not sensible,” you are correct. That seems far-fetched to me.

  • randommuser

    To athanasius @41

    Actually, if you read Barnes last comment (#14), he also agreed that Craig has not demonstrated any contradiction. If you have time please also read some of the later comments about the possibility of infinite universe and about the Hilbert hotel paradox.

  • athanasius

    To randommuser:

    I don’t read Barnes’ last comment the same way; of course Craig has not demonstrated that the mathematical CONCEPT of infinity is contradictory under the rules of transfinite arithmetic–Craig agrees that it is not. But isn’t Barnes citing Ellis and Stoeger in support of Craig’s position that “an infinite is no where to be found in REALITY” (only as potentiality)? Thus, the series of all events can extend toward a potential infinite in the future, but not into the past, since you would then have an actually infinite number of events–which under Hilbert’s principles is “no where to be found in reality”? If not, perhaps Prof. Barnes can post again to clear it up.

  • Craig McGillivary

    How exactly is William Lane Craig not a crackpot? Krauss incorrectly assumed that Craig accepts evolution, but he doesn’t. Go watch his debate with Shelly Kagan in which Shelly Kagan performed quite well. I think its pretty clear in that debate that he doesn’t think that humans evolved from primates. I don’t know whether debating him is a good idea or not, but it seems like Krauss should have known this about him before he agreed to a debate.

  • Mike

    Just for general information, here is a quote that I think sums up nicely why there just simply can’t be a God (or any other similar explanation for things):

    “I don’t believe in the supernatural. My principal negative reason is that there is an infinity of mutually inconsistent accounts of supernatural entities, between which reason cannot distinguish. Were I to accept the offer of one which, as it were, knocked at my door offering an underlying meaning in return for my agreeing to suspend my critical faculties, I should have no decent reply to the next one that knocked and asked ‘Why did you not choose me?’

    My principal positive reason is that, for various reasons (about which I am writing a book, The Beginning of Infinity), I have come to the conclusion that the world is fundamentally comprehensible — but in a way that rules out the possibility that any ultimate explanation can be discovered. For the latter would necessarily be in terms of entities and attributes which themselves cannot be explained. I expect every true answer to create not closure, but a better question. To seek a final answer is to hope that everything beyond that is incomprehensible. And since that move is always available to shore up any false theory, it must be a mistake.”

    – David Deutsch

    By the way, the referenced book has just come out. I’m hoping it will be at least as good as yours Sean ;)

  • Kevin

    “I don’t believe in the supernatural. My principal negative reason is that there is an infinity of mutually inconsistent accounts of supernatural entities, between which reason cannot distinguish. Were I to accept the offer of one which, as it were, knocked at my door offering an underlying meaning in return for my agreeing to suspend my critical faculties, I should have no decent reply to the next one that knocked and asked ‘Why did you not choose me?’”

    This reminds me of a quote from Stephen Henry Roberts:
    “I contend that we are both atheists. I just believe in one fewer god than you do. When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours.”

  • Mike

    @ 47 Kevin,

    An even more brief summation of this negative reason!! Thanks for that.

  • jcm

    The entire debate can be watched at http://mckimmon.online.ncsu.edu/online/Viewer/?peid=c71f72ecead9438faf30bb39b4b1c3051d (note: the audio is not that great).

  • bad Jim

    I’m leaving a comment here because the paper our host referenced discusses fine-tuning arguments for the existence of God, which assert, basically, that the existence of humans proves the existence of God. Such arguments rarely state their crucial premise, which is that humans are the purpose of the universe. (Otherwise, why is it evidence for God instead of Fred? Or Wilma?)

    That the universe allows life to exist, is proof of God only if God necessarily prefers living organisms; that it allows us to exist, is only proof of God if there is some reason to think God actually wants us.

    It’s insanely narcissistic.

  • The Dude

    Dude i learned more from the comment section than any one of the debtors. If WLC is a hardline creationist(i.e. Evolution false, Miracles happen, fine tuned universe, heaven, hell) How can we take anything he says more serious than Ken Ham? The real question is how are you so sure its one god instead of multiple gods?

  • In Hell’s Kitchen (NYC)

    Craig’s approach is lifted from the post-modernist “thinkers” defrocked by the Sokal Hoax.

    In a sane world doing the defrocking once would have been enough…but alas, this is 21st
    Century Ahhmurica we’re living in…sigh…

  • Stanisloki101

    Craig does not do as well when up against actual experts in their field. This can be seen clearly seen in his debate with Ehrman where he made a mistake on “embellishments” in the Gospels and spent the rest of the debate running from the historian, opening himself up to the charge that he’s not one. This was the dilemma he faced with Lawrence Krauss. Craig’s (and many of his fans) incredulousness that “2+2=5″ (where “2″ has higher values) only serves to underline the fact that he is a not a scientist. Indeed, his critique of Harris’ “controversial ideas” ignores the fact that his ideas on cosmology are not only not accepted by the scientific community, unlike Harris’, they are largely ignored.

    The Krauss, Harris and Erhman debates mark a time when Craig has jumped the shark. When pitted against the actual experts in the fields he seeks to imitate (and ever so slightly allow for the impression he is a member of) at best all he can do is bump heads. That might seem impressive considering that he’s not a scientist or historian (and is arguably a philosopher), but each of these fields demand contribution, not a slick and coached debater who’s only goal is to quote mine well enough to prove his particular deity.

  • http://liz-n-val.net v. goroshko

    We wonder if E=C, entire cosmic content spatially constantly propagates with light/speed(E is any referent & C is light velocity in vacuum), requires divine help (when it’s doing just fine) without metaphysical inventions!!!!!!!??????? This new physics explain clearly “Information Conservation Law” – V. Goroshko

  • http://carneades.aimoo.com Carneades

    The actual infinite is the potential one, arrived one day at a time forevermore; the successive addition is the potential at work-never ending! So, WLC prattles howlers!
    What a joker! He begs the question of a starting point!
    He colossally begs the question of the Resurrection; we don’t know who really were these supposed eyewitnesses, who were predisposed to have hallucinations,each seeing him differently, the rectitude of the writers who contradict each other and for sure it would take incredible evidence to overcome the presumption of naturalism [ Google that.].
    We never have known of resurrections, and since no one can vouchsafe the credibility of that one, it itself confirms Hume’s corollary about miracles to the preumtion of naturalism.
    Deist, Jako Miklos in ” Confronting Believers,” agrees with Col. Robert Green Ingersoll and Lord Bertrand Arthur William Russell about that mere man,that jerk! Calling him a moralist is as Miklos notes- the scam of the ages!
    Besides as we only know of minds in brains attached to bodies, any disembodied being would have no body and thus cannot possibly exist without a mind in a brain, per the argument from physical minds. We gnus will not permit theists to gainsay that. They must also without scriptural support provide evidence for Heaven and Hell and contra-causal free will. We dare call their bluff- and hubris!
    Yes, we gnu atheists can without traversing the Cosmos or being omniscient ourselves, flat out proclaim that God cannot possibly exist! Google the ignostic-Ockham and ignosticism to further fathom that.

  • Donald Rumsfeld

    That Luke Barnes guy really got raked over the coals. It a shame to see an astronomer try so desperately to argue a viewpoint to support intelligent design arguments.

  • Matthew Saunders

    Sean,

    I <3 things like this where I get to hear the interpretation of 'what happened' after a debate. With just 2 people, such different interpretations.

    I'd hazard a guess that it 'twould be similar for the audience members.

    That's why police, when interrogating multiple witnesses, they try to talk to them individually and ASAP. Before the 'communal story' happens.

  • Daniele di Naples

    I agree with Barnes. Your presentation of Craig’s argument against the actual infinite is trite and devoid of any kind of interpretive charity. And as anathasius pointed out, even if Craig is wrong about whether Hilbert’s hotel , a great deal of learned philosophers and mathematicians (including Hilbert himself) agree with him that there is no actual infinite So it is a claim that merits consideration.
    Krauss was unable to grapple with Craig’s argument or their logical form , unable to understand bayesian probability and the topic of the debate.
    I do think he did seem to enjoy talking about the science , but he spouted a litany of self-contradictory positions and was not able to formulate an effective response to Craig’s affirmative case.
    If you want a good Craig debate Austin Dacey did a good job.

  • Oliver Mattausch

    It is funny that Craig argues that infinity creates contradictions. What about an infinititely powerful being called god in this case? Can he create a rock so heavy that even he cannot lift it … :-) ?

    Just because we humble finite beings cannot contemplate infinity does not mean that it does not exist in some form – making infinity a person and calling it god conveniently solves all the problems for Craig!

  • Pingback: Conditional probabilities and a debate about God (Part I) « The Divergent Series

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Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] cosmicvariance.com .

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