Sophisticated Critique of Many Worlds Explanation of Fine-Tuning

The following essay was recommended to me by Paul Draper. The paper is not a defense of the fine-tuning argument, but he regards it as one of the best critiques of the many worlds explanation of fine-tuning:

Roger White, “Fine-tuning and Multiple Universes,” forthcoming in Nous
http://www.nyu.edu/gsas/dept/philo/faculty/white/papers/ftmu.pdf (PDF)

Here is some info about the author:

ROGER WHITE, (Ph.D., MIT), Assistant Professor of Philosophy, specializes in philosophy of science, epistemology, and metaphysics. He is currently focusing on epistemological issues in the philosophy of science, particularly those having to do with probability and explanation. His main interests in metaphysics concern matters of identity and essential properties. He is the author of “Fine-tuning and Multiple Universes” (Nous).

About Jeffery Jay Lowder

Jeffery Jay Lowder is President Emeritus of Internet Infidels, Inc., which he co-founded in 1995. He is also co-editor of the book, The Empty Tomb: Jesus Beyond the Grave.

  • http://www.blogger.com/profile/11343561333869773127 debunking the idiots

    Interesting piece. Basically, he argues that the fact that we have just seen a monkey type a whole tome of Shakespeare does not mean that:

    1) if there are other typing monkeys around, the event is more probable;

    2) if there are no typing monkeys around, that we can postulate their existence, which helps to reduce our surprise.

    Makes sense.

    It doesn’t mean, though, that we must accept fine-tuning argument.

    If we previously knew that there are many typing monkeys around, this helps us to reduce surprise.

    And we can conjecture – on independent grounds – that may be indeed many universes. Since there is such a chance, the fine-tuning argument does not work.

    Nevertheless, it seems, one cannot postulate the existence of multiple universes just as an answer to fine-tuning argument, just as one can’t postulate the existence of multiple typing monkeys merely to explain our Super-Monkey.

  • http://www.blogger.com/profile/11343561333869773127 debunking the idiots
  • http://www.blogger.com/profile/11343561333869773127 debunking the idiots
  • http://www.blogger.com/profile/10289884295542007401 Jeffery Jay Lowder

    debunking — You wrote, “And we can conjecture – on independent grounds – that may be indeed many universes. Since there is such a chance, the fine-tuning argument does not work.”

    I’m a critic of fine-tuning arguments for God’s existence, but I’m also a critic of the multiple universe objection to those arguments.

    First, the fact that there is “a chance” that there may be multiple universes is not of obvious relevance to the fine-tuning argument, in two ways. (a) The fine-tuning argument is a probabilistic argument. The fact that multiple universes are possible (and hence that fine-tuning does not have a zero probability given naturalism) does not contradict the fine-tuning argument’s assertion that fine-tuning is much more probable on theism than on naturalism. (b) The fine-tuning argument compares the probability of fine-tuning given theism to the probability of fine-tuning given naturalism (or atheism), not to naturalism combined with the auxiliary hypothesis of multiple universes.

    Second, the hypothesis of multiple universes is not known to be true. I’m not aware of any strong independent evidence–i.e., strong evidence independent of the evidence of fine-tuning–for the existence of multiple universes. At best, it seems to me that there is only weak evidence for the hypothesis of multiple universes, evidence provided by cosmological theories that are highly speculative.

    For these and other reasons, I’m led to agree with your statement, “Nevertheless, it seems, one cannot postulate the existence of multiple universes just as an answer to fine-tuning argument…”

  • http://www.blogger.com/profile/13900843579715907140 John W. Loftus

    Jeffery,

    The fact that a)it is possible that there is intelligent life in our universe, is not negated by the fact that b) there is no evidence of it, although I had respect for Carl Sagan who needed evidence to believe there was intelligent life in our universe before he would claim it existed based upon conjecture.

    I probably haven’t read enough of what you think on this to even be commenting, but are you saying that we should not (or cannot) postulate something for which there is no evidence in order to make our case? Or, are you saying that anything we postulate to make our case will only help our case to the degree there is evidence for it?

    If, however, there are any other universes, then there could be no hard evidence for their existence, correct? But they might exist, and the lack of evidence doesn’t negate their existence.

    I cannot get beyond the fact that the VOID into which our known universe is expanding into must be infinite and never ending. And into a never ending VOID the odds (if we can speak of them in comparison to this known universe we have before us) are that….well….who knows? There could be up to an infinite number of universes even if there is no possible way to have any evidence of them. It’s just a thought experiment. And you claim this is not of obvious relevance “as an answer to fine-tuning argument…”

    Hmmm. Interesting. Who has the burden of proof when there can be no evidence for postulating something either way?

  • http://www.blogger.com/profile/11343561333869773127 debunking the idiots

    Jeffrey, you wrote:

    “(a) The fine-tuning argument is a probabilistic argument. The fact that multiple universes are possible (and hence that fine-tuning does not have a zero probability given naturalism) does not contradict the fine-tuning argument’s assertion that fine-tuning is much more probable on theism than on naturalism.”

    I’m not sure I agree with it. Theists have to establish that it is more probable with theism.

    If we have a reason to postulate multiple universes on independent grounds – or at least their realistic possibility, such as with inflationary BB scenario, it undercuts theistic thesis of God being the only “alternative”. It’s either God or inflation theory’s multiple universes (or mere chance; I’m not sure why God is supposed to be more plausible explanation than chance).

    “(b) The fine-tuning argument compares the probability of fine-tuning given theism to the probability of fine-tuning given naturalism (or atheism), not to naturalism combined with the auxiliary hypothesis of multiple universes.”

    Why is it necessarily an auxiliary hypothesis? I mean, naturalism encompasses all possible universe configurations, so there is no reason to count it as “auxiliary”. Unless you meant something like ad hoc – but I reason on the assumption that the possibility of MU is established by independent means (inflation theory).

    “Second, the hypothesis of multiple universes is not known to be true.”

    Neither is God hypothesis.

    “At best, it seems to me that there is only weak evidence for the hypothesis of multiple universes, evidence provided by cosmological theories that are highly speculative.”

    All of which, and much more can be said about God hypothesis. So, at the very least these explanations are on par.

  • http://www.blogger.com/profile/11343561333869773127 debunking the idiots

    Mr. Loftus, you obviously have severe misconceptions about BB.

    “I cannot get beyond the fact that the VOID into which our known universe is expanding into must be infinite and never ending.”

    What “void”? The universe is expanding into itself.

  • http://www.blogger.com/profile/10289884295542007401 Jeffery Jay Lowder

    debunking —

    You wrote:

    “I’m not sure I agree with it [the fine-tuning argument's assertion that fine-tuning is much more probable on theism than on naturalism]. Theists have to establish that it is more probable with theism.”

    If you replace “theists” with “proponents of fine-tuning arguments,” then I completely agree. (One does not have to be a theist in order to believe that a particular argument raises the ratio of the probability of theism to the probability of naturalism. Agnostic Paul Draper is a case in point.)

    You wrote:

    “If we have a reason to postulate multiple universes on independent grounds – or at least their realistic possibility, such as with inflationary BB scenario, it undercuts theistic thesis of God being the only “alternative”.”

    I think that is a big “if.”

    You write:

    “Why is it necessarily an auxiliary hypothesis? I mean, naturalism encompasses all possible universe configurations, so there is no reason to count it as “auxiliary”. Unless you meant something like ad hoc – but I reason on the assumption that the possibility of MU is established by independent means (inflation theory).”

    It all depends on one’s definition of naturalism. I like Draper’s definition: metaphysical naturalism is “the hypothesis that the universe is a ‘closed system’ in the sense that nothing that is neither a part nor a product of it can affect it. So naturalism entails the nonexistence of all supernatural beings, including the theistic God.” On that definition, the hypothesis of multiple universes is an auxiliary hypothesis, since naturalism (so defined) is also compatible with the hypothesis of a single physical universe. (And note, too, that the auxiliary hypothesis of multiple universes is also logically compatible with theism.)

    You write:

    “”Second, the hypothesis of multiple universes is not known to be true.””

    “Neither is God hypothesis.”

    Obviously, I agree that the God hypothesis is not known to be true. But that reply is not of obvious relevance to the fine-tuning argument for God’s existence.

    Let F = the statement, “our universe is fine-tuned for the existence of intelligent, physical life,” T = the hypothesis that God exists, N = the hypothesis that naturalism is true, and M = the hypothesis that multiple physical universes exist. Fine-tuning arguments for God’s existence can be interpreted as containing a premise that states, Pr(F/T) >> Pr(F/N).

    Since, again, T is compatible with M and N is compatible with ~M, how could M be relevant to the fine-tuning argument? Since we don’t know M to be true, we can’t simply equate Pr(F/N) with Pr(F/N&M;), or Pr(F/T) with Pr(F/T&M;). In effect, consistent with Bayes’s Theorem and the Rule of Total Evidence, we have to use a weighted average formula that takes into account both Pr(F/N&M;) and Pr(F/T&M;), as well as Pr(F/N&~M) and Pr(F/T&~M). I won’t even try to type the formulas into this web interface, but I think if you work them out for yourself, you’ll find that M gives us absolutely no reason at all to think the statement, “Pr(F/T) >> Pr(F/N),” is false.


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