Audio and Video from the Craig v Krauss Debate

If you missed the debate yesterday between William Lane Craig and Lawrence Krauss on the topic “Is there Evidence for God?”, the media from the event is now available.

Timothy and Michael live-blogged the event, and their post presents a good overview of what happened. For deeper commentary, Randy at Possible Worlds has posted an excellent discussion, highlighting some of the key issues that came up. David at the SAA blog also weighs in with his analysis. And Wintery Knight has also posted his own sardonic take on the respective cases put forward by Craig and Krauss.

UPDATE: The votes from the audience have been announced: 286 for Craig, 130 for Krauss, and 100 called it a draw.


18 replies
  1. Stuart McEwing
    Stuart McEwing says:

    On the question of the debate Craig was the clear winner. Pr(G|E & B) > Pr(G|B). Easy win.
    On the idea Pr(G|E & B) > .5 Craig was also the clear winner. Krauss' pop level objections were completely undone.

  2. UpAndAtom
    UpAndAtom says:

    This was a really interesting debate. Thanks for linking to it!

    Stuart, the problem is that E + B simple equals B.

    For example, I could switch the greater than sign around and then make E stand for Evolution, and claim that god is less probable given evolution than he would be without evolution. I think that you would argue around this by doing the same: making E + B = B.

  3. Stuart McEwing
    Stuart McEwing says:

    I have dealt with this objection you mention, namely, Pr(not-G|Evolution) > Pr(G|Evolution) in

    The solution is to add to the B, where B is background information. In the article I specifically add two design arguments, but I suppose one could add any other sort of information (any other arguments from natural theology, personal experience of God, miracles, etc.) to tip the scales in favor of the Pr(G).

  4. Nathan Pik
    Nathan Pik says:


    For those unaccustomed to formal logic, could you expand on what you meant in your initial statement re – the debate?

    ty in advance.


  5. Stuart McEwing
    Stuart McEwing says:

    Sure Nathan,

    For there to be evidence for God means that Pr(G|E & B) > Pr(G|B).

    This is to say the value Pr(G|E & B) is greater than Pr(G|B). The value Pr(G|E & B) is the probability of the hypothesis G (God's existence) on E (the evidence or any consideration or indication apart from B) and B (background information). The value Pr(G|B) is the probability of the hypothesis G (God's existence) on the background information alone. Since its obvious that the probability of God's existence rises when reasons for his existence are taken account, the answer for the question of the debate (Is there evidence for God?) is an affirmative "YES!"

    Now that doesn't mean God exists. It simply means that there is evidence for God's existence if one can show that there are reasons (general considerations) that favor supporting God's existence. To do this Craig used his arguments from the contingency of the universe, the beginning of the universe, the existence of objective moral duties and values, and the resurrection of Jesus.

    To make belief in God reasonable with respect to Locke's evidentiary principle (one should proportion their beliefs in accordance with the evidence) one needs to argue that the existence for God is more probable than not, that is Pr(G|E & B) > .5

    This is done by showing the arguments in favor of God's existence deductively as assessing if the premises are more likely true than they are false. Since Krauss' objections to these arguments were undone almost as soon as he said them, Craig clearly had the upper hand in the debate.

  6. UpAndAtom
    UpAndAtom says:

    Stuart, you have completely missed the point of that probablility inequality. Craig can't win by stating that probability equation. It doesn't mean anything on its own. What matters is the E,the evidence. And as I was trying to point out, all of the evidence that Craig came up with was merely Background, not evidence. Just as you would consider the Evidence for Evolution as merely background and proving nothing.

  7. Stuart McEwing
    Stuart McEwing says:

    No, no, no.

    The evidence matters when the question is if God exists or if it is rational to believe in God's existence. The question was if there is any evidence, i.e. if there is anything to plug into the E of the equation. Now the E of the equation is any consideration towards thinking that the hypothesis is true (i.e. God exists) that is not apart of the background information, B. Thats by definition. It doesn't matter what you put in the background information because B is balanced on both sides.

    Now, if you put all those considerations (the argument from contingency of the universe, from the beginning of the universe, from the existence of objective moral duties and values, and from the resurrection of Jesus) into the B, then you could consider that there is no evidence of God (at least presented – I cold think of other arguments or personal experience, etc.), but then on the background evidence alone you would be justified in believing God exists, i.e. Pr(G|B) > .5

    But is that really what you think Krauss was arguing for?

  8. Stuart McEwing
    Stuart McEwing says:

    Amendment, "…but then on the background evidence alone you would be justified in believing God exists, i.e. Pr(G|B) > .5 " That is, if the premises in the deductive form of the arguments given are more likely than not.

  9. Randy Everist
    Randy Everist says:

    UpandAtom, the problem is that no one of whom I am aware thinks the cosmological argument is part of background knowledge. It may be parsed or broken into bits that ultimately reduce to background knowledge, but reduction is not in view, but deduction. That something is ultimately based on collections of background knowledge does not mean that something is itself background knowledge. Further, even if we grant all of your "evidence against God" as such (which I think is highly problematic in any case, at least without argument), this still tends to be counterbalanced by the weight of consideration for the positive evidence alone. Especially since E is considered as evidence for God's existence. Essentially, Craig's point was a walk in the park, since all he had to do is show God's existence is more probable given his arguments than it would be without it. He made the debate more interesting by charitably attempting to argue that the probability of God's existence is greater than .5, but that wasn't the debate topic.

  10. UpAndAtom
    UpAndAtom says:

    Ha, you might need to broaden the people you know randy. :)

    I actually agree with you that the cosmological argument is not part of the background knowledge. It's not knowledge at all. It's nonsense.

    There are several problems I have with it, and these are completely unsolved as far as I know:

    1. Everything that begins to exists does NOT necessarily have a cause. As was discussed in the debate, 'quantum' particles pop into existence all the time, and all over space, and they are completely random, and without cause. Firthermore, Krauss actually discussed this idea, suggesting that universes pop into existence randomly just as particles do.

    2. I don't even know what it MEANS to claim that the universe began to exist (No one does and the sentence is meaningless) because time is a property OF the universe.

    3. To use a causal argument to claim that there must be a god is just silly because then what caused god? And to claim that god is inherently 'necessary' or uncaused is empirically offensive and special pleading, making it obvious that what is at the centre of the argument is not a motivation of good sense and reason but the reality-defiling determination to prove that a god exists no matter the nonsense along the way.

    Given the above then, the conclusion "The universe must have had a cause" is utterly unfounded – at least upon these first two premises – and the conclusion that an uncaused being exists is even more left-field and other-wise motivated.

  11. Stuart McEwing
    Stuart McEwing says:

    Those three objections to the Kalam cosmological argument are eminently answerable. Have been answered many times. And some even addressed directly by Craig in this debate.

  12. Bnonn Tennant
    Bnonn Tennant says:

    UpAndAtom, it doesn't seem like you've done any real research into the Kalam argument if you think those three objections are serious problems for it.

    1. You seem to be falsely equating randomness with uncausedness. But just because something is random does not mean it has no cause. Equally, just because we don't see a cause for something doesn't mean that one doesn't exist. In fact, Krauss insisted in the debate that all these quantum level events are deterministic. That the laws that govern them are deterministic. I guess he'd know. But if such events are deterministic, then they are certainly caused by something.

    2. There is a distinction between logical and chronological causation. We can conceive of the universe having a logical beginning, even if we know it did not have a chronological beginning. This objection strikes me as particularly strange. Do you not believe the universe began to exist 13.72 billion years ago, as Krauss claimed? Is this not a scientific fact?

    3. There's nothing "empirically offensive" about claiming that some things do not require a cause. In fact, if there is, then you are contradicting yourself as regards point 1. In any event, if something does not begin to exist, then it is nonsensical to claim that it must have a cause. Like Krauss, you don't seem to understand the distinction between contingent and necessary objects; nor that you can't have contingent objects going back indefinitely. That's no better than turtles all the way down, if you get my reference.

  13. UpAndAtom
    UpAndAtom says:


    1. Nothing is random with determinism, events are pseudo-random. Quantum events really are random. There is no cause. Quantum events are deterministic in that they are 'governed' by probability, but they really are undetermined apart from that. For instance, particles pop in and out of existence is empty space all the time and the length of time they exist for is a probability distribution. But there is no mechanism which determines how long a particular particle will exist. It really is completely and purely random and undetermined. Found this:
    Why is it that when science is convenient it is quoted (e.g. the big bang was a 'beginning') but that when it is not convenient it is ignored: "just because we don't see a cause for something doesn't mean that one doesn't exist".

    2. This is a point where philosophy ceases to be useful. We can conceive of lots of things, but they don't have to have anything to do with reality. I have yet to see an instance of non-temporal causation. You speak of a distinction. Please tell me what that (real, exemplar-ed) distinction is!

    The big bang is an extrapolation of observations, and if we extrapolate the movement of the stars and galaxies we get the 13 billion years figure. But our models don't account for t=0. They don't work there, just like they don't work in black holes – it is a complete mystery – for both! Also, GR is not the end of the story. It's not correct because it doesn't work with QM.

    I do not believe that the universe began to exist. I can't, because the phrase "time beginning" is incoherent, is it not? It tries to take the concept of time outside of time! It makes no more sense than to say that "the universe is located…" Where is this extra-universal space and how do I get there? Where is this extra-universal time and why can't I get there?

    But I do not believe that it makes sense to make statements about the universe, for they are necessarily incoherent.*

    3. Yes, thanks for pointing that out, you're right this is contradictory with point 1. I still do find it empirically offensive to claim that god is "necessary and un-created". Because I don't think it was arrived at empirically; it was arrived at as an excuse to keep believing in god and not have to consider awkward questions. Compare this to QM randomness: physicists were dragged kicking and screaming 'till they just had to admit that reality was not how they wanted it to be. This was very empirical.

    I think I agree with you that ~'if something does not begin to exist, then it must not have a cause'.

    I don't think I believe in necessary objects. But I'd be interested in discussing these – of what do you speak?!

    I can see why turtles all the way down is somewhat undesirable. (This platonic(?) thinking is predominant at this site, I think.) But, as Krauss points out, we can't sit here telling the universe that it is undesirable and how it should be. It has to tell us, there is no other way.
    My views on the universe would be very uncomfortable to you. When I was a kid I used to think of what was behind reality, and what was behind that, and that, and that, and my mind would hurt. As it happens a comment by a colleague today brought me through this experience once more. A god who is final solves this 'problem'. I wonder whether perhaps the difference between your thinking and mine is that I have come to terms with these turtles. They are real, but so what? I'm not going to ignore reality.

  14. Bnonn Tennant
    Bnonn Tennant says:

    Hey UpAndAtom, you raise some good objections. Let me have a crack at them:

    1. You say quantum events really are random. But the article you yourself cite in favor of this says, "Ironically, quantum mechanics is one of the best prospects for a genuinely deterministic theory in modern times! Even more than in the case of GTR and the hole argument, everything hinges on what interpretational and philosophical decisions one adopts." So if anything, the article is conceding my point: that you can't derive the conclusion that "There is no cause" from the observation of "We don't see a cause".

    But let me grant that quantum events are genuinely random. How, then, does that equate to them not having a cause? If some quantum event occurs probabilistically, like the decay of an isotope or the appearance of a virtual particle pair, how do you get from "The event was random" to "The event was uncaused"? I think you either need to show that a random event is necessarily an uncaused event, or that a random event is the same as an uncaused event. Otherwise I don't really have any reason to buy your objection.

    2. You say, "This is a point where philosophy ceases to be useful." But why? Since science is literally based on philosophy—ie, on philosophical principles like the uniformity of nature, methodological naturalism, induction and so on—then if philosophy ceases to be useful in regards to some question, then presumably science ceases to be useful as well.

    You also say, "We can conceive of lots of things, but they don't have to have anything to do with reality." Well, of course, but that doesn't mean that they don't have anything to do with reality. For example, you are conceiving of other people conceiving of lots of things, and those things not having anything necessarily to do with reality. So…does your conception of other people's conceptions have anything to do with reality?

    You also complain that you have yet to see an instance of non-temporal causality. But so what? I'd wager you have yet to see any protons, either—what should we conclude about them, based on your not having observed them? Moreover, your saying this just presupposes what you're trying to prove. Unless you can show an airtight theory of causality where causation must always involve time, your objection really doesn't hold any water. In fact, some quite robust theories of causality hold that causation is always simultaneous, and does not intrinsically require chronological progression at all. (Kant's famous iron ball causing an indentation on a pillow is an example of simultaneous causation where time is not necessarily required.) Moreover, you'd also have to provide a staunch defense for an A theory of time, over a B theory of time, in order to show that we can't assume a tenseless cause to a complete spacetime. I guess I don't need to point out that you haven't done any of these things (:

    3. You say it's empirically offensive for God to be necessary and uncaused, because this was not arrived at empirically. But so what? God is not something that can be empirically tested, so it doesn't seem to even make sense to complain that we haven't arrived at conclusions about him via empirical means. It would be like getting cross because we haven't empirically tested the laws of logic before deciding that they must always hold; or that we haven't empirically tested ethics before deciding that people ought to do certain things; or that we haven't empirically verified that other people even exist before drawing the conclusion that they do. But none of those are reasonable objections, surely?

    I don't think I believe in necessary objects. But I'd be interested in discussing these – of what do you speak?!

    Well, it seems like you're trying to eat your cake and still have it. Just because you don't believe in necessary objects doesn't mean your belief has anything to do with reality, right? (: Same with the "turtles all the way down". Just because you think it's okay for the universe to be "uncomfortable" doesn't mean it is.

    So anyway, necessary objects: the laws of logic, numbers, etc. These are things that could not fail to exist. To claim that they could not exist is to contradict yourself, either implicitly or explicitly.

    And as for turtles all the way down, well, like Krauss, you're making the mistake of confusing our ability to mathematically model infinities with the ability of actual infinities to exist. But again, it's logically demonstrable that actual infinites cannot exist. So our positing a God to avoid an otherwise insurmountable problem (infinite regress) is hardly some kind of weakness, where we just "can't handle" the way the universe really is—rather it's an observation of how the universe really cannot be, and an effort to understand how it can be. It seems really strange that pro-science people would diss this methodology. I mean, otherwise I can just turn your objection around on you and say, for instance, "Well, I can see how it would be undesirable for both relativity and quantum mechanics to be true, or how it could be undesirable for the principle of uniformity not to hold and thus make all science impossible, but we can't sit here telling the universe that it is undesirable and how it should be." That objection cuts both ways. Careful playing with your two-edged sword.

  15. Lorena
    Lorena says:

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  16. milk
    milk says:

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