Thursday, October 21, 2010

Can there be evidence for God? Can there be evidence for a Halting Oracle? For the Hidden Variables Interpretation?

The volley between Jerry and PZ over whether there could even in principle be evidence of a "god" continues apace, with other bloggers weighing in as well. Okay, my turn!

First of all, I think Jerry and PZ are both failing to define their terms clearly enough. Both of them seem to recognize this problem, but then just go on ignoring it, like everybody "knows what they mean." PZ has made a whole lot of noise, some of it surprisingly sloppy (am I mistaken, or in one post did he argue that "I haven't ever seen any of this evidence" implies that "no such evidence could even in principle exist"?!), but if I may, I think I can boil his argument down to two assumptions, the first of which I definitely agree with, the other which I think is controversial:

1) Anything "supernatural" by definition does not exist, because if something we previously though were supernatural were shown to exist in the physical world, then it would be, by definition, "natural."

2) A necessary feature of a prospective god is that it must be supernatural.

Fair enough, but it seems to me to be begging the question.

Jerry, on the other hand, seems to reject the first premise! He seems to think there is a definition of "supernatural" that would allow a thing with that trait to exist -- even though it wouldn't exist as part of the "natural" world? I don't understand that, and I would need a pretty specific definition of "supernatural" before I would accept it. A number of commenters at WEIT have mounted attempts, but I remain unconvinced by all of them.

So my opinion had been somewhere in between... I reject the possibility of the supernatural (by definition!), but I don't think that possessing supernatural traits is a prerequisite to godhood. Therefore, I thought that, while the evidence would have to be pretty staggering, we might imagine sufficient evidence to convince me of the existence of a being worthy of the appellation "god".

An exchange with Ben Goren has altered my thinking with this somewhat. I still think it's a question of definition, but he has convinced me that there is a particular aspect that is rather fundamental to most useful definitions of "god(s)", and that if I accept that as part of the definition, I must state that I cannot imagine any evidence that would convince me of the existence of god(s). I will stop just short of saying there can never be such evidence, but a case for this type of god(s) would have to first address some important theoretical objections before the evidential case could even begin.

First, the critical aspect of the definition. Let me try and state it as specifically and formally as I can:

Any being which is referred to as a "god" must either a) have created sui generis everything that exists, or b) be part of a pantheon that is either collectively responsible for creating or contains one or more members who created sui generis everything that exists.

If we further assume that said "god" has any type of volition, which seems reasonable given the apparent features of all major religions (oh noes, apophatic theology FTW!), then Ben Goren argues -- and I agree -- that such a god cannot by definition exist. If it exists, and it created everything that exists, then it must have created itself sui generis, and there is not even in principle a way by which a being with volition could create itself sui generis. It just doesn't make sense. It would have to have had volition first, and volition is something, therefore it's not sui generis!

Of course, this is a logical proof, and apparently sound logical proofs have turned out to be wrong before based on hidden assumptions that were not apparent until some new leap forward in understanding was achieved. So I don't reject the possibility that it could be wrong. And FWIW, I stand by that, despite the fact that I am about to constrain it even more.

Ben Goren responds that this may be so, but that the soundness of this proof is comparable to the soundness of the proof of the Halting Problem. Of course, I have not formalized it (probably someone somewhere has?) but in general I agree with Ben. So could there be evidence that would convince me that a Halting Oracle could be implemented in a Turing machine? Well, maybe, but I can't imagine it.

I'd prefer to talk about the Hidden Variables Interpretation of Quantum Mechanics, mostly because it's fresher in my mind than the Halting Problem. Bell's Theorem proves that, unless QM is just plain wrong, there can be no hidden variables. (And we're not talking wrong like "Newtonian mechanics is wrong because it over-generalizes a special case of general relativity", we're talking wrong like "Aristotelean physics is wrong") It does so by making predictions on the behavior of entangled particles, known as Bell's Inequalities.

In a nutshell: If there were some hidden variable, then the sum of the probabilities of a certain set of outcomes should be greater than or equal to the probability of another outcome -- because if that latter outcome were true due to some hidden variable, it would entail that all of the other outcomes would also necessarily have been true, if that's what we had been measuring for.

Turns out Bell's Inequalities are violated all the frakkin' time in quantum mechanics, and we can confirm this with observation. And confirm it we have -- again, and again, and again, and again. Bell's Inequalities just plain aren't obeyed. This is a fact of reality.

So any consistent theory of physics which attempted to predict the outcome of quantum interactions based on a heretofore unknown variable -- some trait or state of the particle that we didn't yet know about -- would have to begin by explaining how Bell's Inequalities were violated. If it couldn't do that, then regardless of whatever kinds of copious evidence is amassed in its favor, we would be justified in discounting its accuracy.

(That said, if somebody was able to, say, consistently predict a priori where an individual electron would hit the screen in the double-slit experiment, and this experiment were easily replicated... then we'd be wise to listen up to her theoretical explanation, even if that explanation failed to address Bell's Theorem. Unless and until that were addressed, though, I think we would still provisionally assume that there was some other phenomenon facilitating the prediction, rather than a heretofore hidden variable.)

So it is with a Creator god. I cannot imagine what evidence would convince me of the existence of a Creator god, and any such case would have to begin by mounting a satisfying explanation of the apparent existential contradiction discussed above. Unless and until that contradiction were satisfactorily addressed, we would have to provisionally assume that said god(s) came into existence via some natural process, rather than the other way around -- regardless of any other evidence. That includes your 900 foot Jesus scenarios. Heal as many amputees as you want, turn the Pacific Ocean into 2001 vintage California Cabernet Savignon, prove to me the existence of an afterlife, maybe even show me that you are powerful and benevolent enough to be worthy of worship -- I still ain't buying the Creator thing until you explain that part of it to me.

Now, maybe the Creator aspect is not entirely necessary. It depends on your definitions, of course. I think that's part of where Jerry's going with it (though I think he fails in refusing to nail down what he means by "supernatural" in a meaningful way) and I think that's okay. It leaves you vulnerable to challenges like "are the programmers of the Matrix gods?" or "Is Q from Star Trek a god?", but I don't necessarily think those challenges are insurmountable. (If the programmers of the Matrix made me sing crappy songs, asked for ten percent of my income, and played mean tricks like "Stab your son -- psyche!", then yeah, that pretty much sounds like Yahweh to me...)

So there's my final answer: If you mean the Creator god, then no, I cannot imagine any evidence that would convince me -- although there is an important caveat that my inability to imagine such evidence does not necessarily rule out its existence, though it puts some pretty strict conditions on what form the evidence would have to take. If your definition of god is more expansive, of course, then all bets are off.


  1. 1) Anything "supernatural" by definition does not exist, because if something we previously though were supernatural were shown to exist in the physical world, then it would be, by definition, "natural."

    You definitely agree with this, but I definitely disagree with it. I see no reason that we can't imagine a being in this natural world that has supernatural powers and can break physical laws.

    I don't think that 'supernatural' is a term that makes much sense at all, in fact. How about just saying that a god must be able to break physical laws? Is that palatable?

    Any being which is referred to as a "god" must either a) have created sui generis everything that exists, or b) be part of a pantheon that is either collectively responsible for creating or contains one or more members who created sui generis everything that exists.

    Why? Why everything?

    Suppose in another universe, U1, a being evolved by the normal physical laws of that universe. This being then created another universe, U2, and created life in it, too. The physical laws in U2 would (in this imaginary scenario) be constrained and much different form the ones in U1. Beings in U2 inferred that they evolved by natural means, and weren't created. However, when the U1 creator wanted to, he could appear in U2 an explain it all. Yes, U1 being would be a natural being in U1, but a 'supernatural' in in U2. By your definition, the U1 being would be a god in the eyes of U2 beings. No?

  2. 1) If there is something in the physical world which can "break" physical laws as we know them, then that means the physical laws are wrong. It may be that Newton's Second Law is "F = ma + J", where J is the Jeebus Coefficient, but that would still be a physical law, IMO.

    But point taken. I'd phrase it as saying that the real physical laws do not place any restrictions on the being's actions.

    2) It has become clear in a number of discussions I've had that many people wouldn't call that a 'god'. But you would. So that's fair.

    I guess I'm just trying to clarify that, while I can imagine evidence that would convince me of the U1/U2 style 'god', I cannot imagine evidence that would convince me of the U* style of 'god'. For any individual person, whether they consider U*-ness to be a prerequisite to godhood, well, that's their business.

    In the end it's all rather silly, I suppose. :)

  3. I frankly think that the definitional escape that refusing to call some very powerful being (as described) a god is the silly thing.

    On top of that, I continue to disagree that a god must be supernatural, which seems to be the main point that people are making everywhere.

  4. I definitely agree with your second paragraph -- I do not by any means find that to be a necessary feature.

    As far as the "definitional escape", I see your point, but on your side, you must answer questions like, "Are the programmers of the Matrix gods?" and "Is Q from Star Trek a god?"

  5. While I initially sided with PZ, I am not so sure anymore. Let's imagine that there were a number of events that occurred, and could be reliably observed, that neither obeyed the laws of physics or their own internally-consistent laws. We're at this point not talking about something like quantum phenomena that obey their own rules in certain circumstances, but phenomena that occur without any discernible rules whatsoever.

    If we were confronted with such things, we would build a scientific model for it - a model that says that most of the time there is order, but sometimes random, unexplainable shit happens with no seeming pattern. Calling this model "God" wouldn't be outside the realm of possibility, since it is evidence of an unknown force that interacts with the material world in ways that defy understanding.

    If such a set of circumstances were to be observed, I'd say that there is evidence for "God" in the same way there is evidence for "evolution" - a phenomena that is described by a model derived from observation.

    However, since there's no evidence of such a state of affairs, and since it bears absolutely no resemblance to any kind of God that anyone believes in, it's entirely reasonable to say that there is no evidence.

  6. I could definitely concede that Q is a god, whether he breaks our known physical laws in a manner beyond explanation, or if it can be explained by a "wider" set of laws that we as "lesser beings" aren't subject to.

    Crommie, last paragraph... No, there is no such evidence, but that's not the question. "We" all agree that the question is a purely philosophical one, and that no gods exist.

    However, I don't agree that it matters that a potential god-like god does not bear resemblance to any of the current myths of humans.

  7. Bjørn: If by your definition Q is a god, then you are in the minority position -- but since it is purely a matter of definitions, I don't really have anything to say about it's validity.

    By a definition that would allow Q into the God Club, yes, quite clearly there is in-principle evidence that could convince me of such a being's existence. On that I whole-heartedly agree with you.

    crommunist: Your idea of a series of events which refuses to obey any internally consistent set of laws is intriguing... That might be the elusive definition of "supernatural" we are looking for... but even then, I'd be tempted to say, "Oh, the laws are consistent after all: It's whatever Jeebus says." Which would count as a god by many people's (though not all's) definition, of course. But I still might obstinately insist such a god would still be "natural".

  8. Why would Q not be a god to you, then? Suppose he, or another member of the Continuum, actually also created life on Earth one week 6014 years ago for kicks (and by the way thought it was crazy funny to make it replete with fossils, etc.), and have visited many times since, answering some prayers and performing other miracles. And had a son. Would he not be a god, then?

  9. To me? Well, I'm not really decided. I'm going to take the coward's way out and not commit to a position. I'll just say that you appear to be in the minority position (among theists and atheists alike).

    FWIW, your addition of "also created like on Earth", etc., makes this consistent with a comment I made at WEIT:

    Depending on humanity’s history of interaction with [the programmers of the Matrix], it might be fair to call them gods.

    That's why I'm trying to separate the question into the "as powerful and oppressive as Yahweh" set of criteria vs. the "Creator of Everything" criterion. I think both questions are valid, and have clearly different answers.

  10. @James - Today's xkcd is a pretty decent representation of my idea:

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