Friday, June 1, 2012

Bob Murphy on Fine Tuning and the Existence of God

Bob mentions fine tuning here.

I never quite understood why people get so excited about alleged “fine tuning”. The multiverse idea seems quite plausible to me, but I think even that overcomplicates it.

If certain conditions are required for us to exist and observe reality, and if we do exist and observe reality, then you really only have two options:

1. We exist and observe and the universe does not meet these conditions, or
2. We exist and observe and the universe does meet these conditions.

The conditional probability of 1 is zero, so the conditional probability of 2 is one. Far from being something to marvel at – an apparently “fine tuned universe” seems like a logical necessity to me. If you don't like multiverses, take one expanding and collapsing singularity (our universe).

I personally  don't see what's especially hard to accept about a mutliverse. It's like aliens - if you understand that life evolved on Earth you shouldn't have all that much trouble accepting that it did elsewhere. If you don't have trouble accepting that our universe was generated in a Big Bang, it shouldn't be all that hard to accept that other universes emerged similarly. Certainly when a better informed person tells you they expect that is the case, nothing in your experience should lead you to balk at the prospect.

The alleged fine tuning of the universe doesn't really do anything in either direction as an argument for God, and that's my point. It strikes me as a non-argument.

UPDATE: And we should be careful to not take the fine tuning argument too far either. It's often framed as "there can't be life without certain physical constants", so a God presiding over life would be very interested in these constants. But my understanding is that its not just an issue of life; matter itself would not exist without these constants. So there's nothing especially pro-flourishing-life about the fine tuning issue. Its even baser than "for living things to exist and observe we need x, y, and z" - it's that "for stuff in general to be stuff we need x, y, and z". Again - this is less an issue of awe and wonder and more an issue of logical necessity.

9 comments:

  1. Well, it goes a little further than that. Sure, physical constants are required for matter to exist, but presumably, for some values of universal constants, matter would exist, but not life. (or potentially, not intelligent life.)

    That said, I agree with you. I think the multiverse solves the "incredible luck" problem. Without the multiverse explanation, it is quite possible that we would not actually exist. I would contend that such a thought makes people highly uncomfortable and that the multiverse hypothesis can help with that discomfort.

    On a side note, the multiverse hypothesis makes me highly uncomfortable because it seems definitionally problematic because it implies the existence of things outside our universe. But given that our universe defines what it means to exist, I don't think there is much meaning in the multiverse hypothesis.

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  2. Personally, I don't think the multiverse conjecture is relevant at all. Whether there is only one universe or an infinite number we're still faced with ...

    1. We exist and observe and the universe does not meet these conditions, or
    2. We exist and observe and the universe does meet these conditions.

    It makes no sense to me to calculate the odds that our universe were to come to exist from the perspective of the past. Going far enough back in time the present has an infinitely small chance of happening. Hence, the "fine tuning" argument appears polemic to me.

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    1. Not to bring up the absence of "time" outside our universe.

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  3. I agree with your shrugging off of fine tuning as a proof of anything in particular (and I'm with Prometheefeu on the problematic aspects of "multiverses" too). Some off the cuff thoughts on fine tuning that may or may not be substantial:

    -I don't even play a physicist on TV, so I may be totally wrong on this, but I don't understand how the heck scientists can even say much about how finely tuned the universe needs to be to support "life" or "matter". I mean, what is life, really? Just a complex system of sustained disequilibrium with the outer environment or something like that, right? When you boil it down to a form like that, I think it's quite plausible to imagine life amidst vastly different physical laws, even if it would be difficult to establish what it would look like. Even more so with matter. I mean (and this is an honest question, again, I'm no physicist), are the physical laws of the universe and the constants underwriting them the sort of things that are even meaningful without matter? When you talk about a differently tuned universe that is immaterial because physical laws are such that stuff can't arise, I don't even know how to make sense of that. But maybe I'm misunderstanding the consequences of an "out of tune" universe vis a vis matter.

    -Presumably if God could be conceived as a fine tuner of the physical laws of the universe, one could also take a step further back and say that God was the one who determined that there even would be a necessity for a particularly narrow band of possible tunings for life and matter to exist. Forget turtles, it's Euthyphro dilemmas all the way down! So long as we are talking about some sort of lawfulness (i.e., a formal necessity for a given situation that precedes any merely descriptive account of it), it seems like the question of divinity (or "ground", if divinity is too hokey for you) is always right there. That's not to say that the question is answerable or even leans towards a particular answer. But I think "law" of any sort begs for meaning, and something like God has consistently been a convincing way of describing lawfulness of various sorts. It's either going to be some sort of God, or law just chasing its own tail. Right?

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    1. I believe Scientists can do mathematical simulations of universes with different laws or physical constants and they don't produce the complexity of our one (stars and galaxies) even ignoring the life question. An intelligence behind the laws of our universe is a more parsimonious explanation than "multiverses", which would require more laws to determine which combinations of laws are allowed.

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  4. "Certainly when a better informed person tells you they expect that is the case, nothing in your experience should lead you to balk at the prospect."

    By definition, no one has ANY information on other universes, nor is it ever possible to have any. The "multiverse" is just an ad hoc hypothesis designed to meet the fine tuning argument.

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    1. If by "information" you mean "data", probably not.

      I think you should know better than writing that last sentence. Multiverse conclusions emerge out of some ways of thinking about both quantum mechanics and string theory. Quantum mechanics certainly isn't ad hoc. There are legitimate criticisms of string theory, but I don't think being a tool to fight the fine tuning argument is one of them. This claims seems awfully self-indulgent to me.

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  5. This claims seems awfully self-indulgent to me.

    With billions of people using the Web everyday, it is unremarkable that you received such a self-indulgent comment.

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  6. The theory of evolution may apply to universes too

    http://library.thinkquest.org/C004367/be11.shtml

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