A Change of Heart on Fine-Tuning

24 Apr

I’ve spent the last few months exploring an unorthodox explanation of cosmological fine-tuning, which I discuss in this article and this talk. Part of my motivation was dissatisfaction with the two more conventional alternatives: God and the multiverse hypothesis. And part of the my dissatisfaction with the multiverse hypothesis was rooted in Roger White’s intriguing article arguing that the multiverse hypothesis doesn’t even explain the fine-tuning. As I said in a couple of recent talks on fine-tuning, it wasn’t that I was happy with the theory I’d come up with; to paraphrase Churchill, the view I was considering seemed to me to be the worst explanation of fine-tuning apart from all the others.

However, I think I’ve just changed my mind on the White article. White’s essential point is that what we want explained is why this universe is fine-tuned, whilst the postulation of a multiverse only explains why a universe is fine-tuned (I’m sure many will right now be screaming “But what about the Anthropic Principle/selection effect????”…see my discussion in the talk from 17:50-24:50.). However, at a recent talk I gave on this topic at Rutgers University, a discussion with Eddie Chen made me appreciate that this distinction collapses if the laws of nature are not contingent, that is to say, if our universe had to have the laws it has (and I’m independently attracted to philosophical views in which this is the case). If our universe had to have the laws of nature it in fact has, then it had to be fine-tuned, so long as it exists. This doesn’t mean that the fine-tuning puzzle goes away; it just turns into a different question. The question is not “Why is our universe fine-tuned?” but “Why does our fine-tuned universe exist rather any of the many very similar universes that aren’t fine-tuned?” Crucially, the multiverse theory can explain this: If there is a high enough number of universes, then there is likely to be one which, like ours, is fine-tuned.

So I’m now back to thinking probably some form of the multiverse hypothesis, perhaps the quantum mechanical version, is the best explanation of the fine-tuning. But I don’t regret exploring my “middle way” hypothesis. It’s philosophically important to explore new theories and explanations, and to try things out. After all, philosophers are supposed to question everything. It’s a shame that our intellectual climate makes this difficult. We pride ourselves on being liberal and free thinking, but it was hard to talk about this stuff. I could feel myself been categorised as “religious” or “new age” just for trying out a view.

Of course, we shouldn’t get lost in flights of fancy, but we should examine the arguments without prejudice. This was the enlightenment aim, but somewhere along the way that aim was replaced by dogmatic adherence to an ideological view of what science is “supposed to look like”. I look forward to the day when the enlightenment ideal of rigorous objectivity overcomes, once and for all, such ideologies.

14 Responses to “A Change of Heart on Fine-Tuning”

  1. Lee Roetcisoender April 24, 2018 at 3:15 pm #

    Philip,

    Rigorous objectivity is quite an ideal, nevertheless, objectivity will never become the prevailing paradigm as long as there is censorship. Censorship comes in two forms:
    1.) Not allowing someone else’s voice to be heard.
    2.) Not acknowledging that voice when it does speak.

  2. Jochen Krattenmacher April 29, 2018 at 10:13 am #

    No offense, but I think you just took a little detour to find what people mean when they say “anthropic principle”. Can’t hurt to roam around a little and clarify terms though ;).

    I enjoyed your blog post about cosmopsychism! Especially the size-of-the-universe argument was unknown to me, it makes me wonder: what significance could that have on sentience? Maybe you are a bit too fast to back-pedal, but anyway there is enough to do on all fronts 😉

    I don’t think you are as alone with your sentiment as you think you are and hope you keep up the thinking-outside-the-box.

    • conscienceandconsciousness April 30, 2018 at 4:58 am #

      I don’t think it’s the anthropic principle: I discuss White’s response to the anthropic principle in the section of the talk I refer to in this post. It’s just that White’s argument doesn’t work if the laws of nature are necessary. I’m not sure what you mean by the ‘size-of-the-universe’ argument, but glad you got something out of the post 🙂

      • Jochen Krattenmacher April 30, 2018 at 9:20 am #

        “for every observer who observes a smooth, orderly universe as big as ours, there are 10 to the power of 10123 who observe a smooth, orderly universe that is just 10 times smaller.”

        It seems a little strange to me asking “why am I not a Boltzmann brain?”, whereas it seems more sane to ask “Why is the Universe is so big?” 😉

        Regarding the anthropic principle:

        I watched that part of the talk, and I didn’t really agree with your second situation where the monkey writes down his sentence (we didn’t actually see the monkey writing, we only find ourselves wondering why he did).

        ““Why is our universe fine-tuned?” but “Why does our fine-tuned universe exist rather any of the many very similar universes that aren’t fine-tuned?””

        I am making an implicit jump from the first to the second question, which obviously spares me a lot of details and insights which one gets by making a distinction.
        I think I cannot follow your argument of contingency, or better, I cannot think/imagine/understand a situation where contingency isn’t given.

        In conclusion, I’ll have to read up at some point 😡

  3. asongforsimeon April 30, 2018 at 1:26 pm #

    Surely, White’s argument would have ruled out the whole category of inflationary explanations, if endorsed. But, even rejecting it, doesn’t Penrose’s objections and the Boltzmann brains problem remain intact? I’m curious why do you prefer the multiverse explanation on philosophical grounds, given that the problem of evil you referred to in the original Aeon essay as an argument against theism is much weaker than those (and not a problem at all for some flavours of theism, namely deism, the simulation hypothesis and various gnostic traditions).

    • conscienceandconsciousness April 30, 2018 at 3:13 pm #

      White’s argument rules out justifying multiverse hypotheses on the basis of fine-tuning, but it doesn’t rule out justifying them on other grounds. The inflationary multiverse hypothesis faces Boltzmann brain worries, but it’s not clear to me that every multiverse hypothesis faces these worries, e.g. I don’t think the quantum version faces these worries. Why do you think the problem of evil is weaker than Boltzmann brain worry? I’m inclined to completely reject classical theism on this basis, although I agree other forms of theism do better.

      • asongforsimeon April 30, 2018 at 5:14 pm #

        Well, the quantum version (if, as I understand it, you’re referring to the Everett Interpretation) introduces its own set of problems, like how exactly, in a strictly materialistic framework, all the splitting universes from non-personal quantum measurements seem to express non identical consciousnesses (i.e., why from my exact copy, down to the quantum level, is not emerging my exact experience? How can they be qualitatively differentiated?). Should be noted that Everett himself was convinced of quantum immortality.

        As for the problem of evil, I would argue it is weaker simply because it is a subjective, extremely ill defined problem. There is the traditional Augustine’s argument of evil being non ontological, but simply the absence of good, so basically the conditio-sine-qua-non for the existence of a world different from God. It’s a consistent view, good as any other.

        But I personally would argue that, in a theistic framework, the problem of evil could easily be reformulated as evidence from evil. For example, you could argue that the inescapable tension between a meaning-searching being and the meaninglessness of the world (which is what Sartre’s characterized as “being condemned to be free”) is an irreducible evil, unlikely to emerge from the evolutionary process (which would have favored psychological adaptation to meaninglessness, i.e. philosophical zombies), and thus pointing to a teleological inclination to generate evil. It’s not like I’m arguing in favor of a specific theistic interpretation, but I think that, confronted with any kind of fine-tuning, metaphysics including teleology are generally less problematic than inflationary ones.

  4. Evan May 2, 2018 at 11:32 pm #

    It seems to me that the crux of the matter is this: is it valid to make probabilistic Bayesian inferences when trying to figure out how the reality we inhabit fundamentally works?

    As far as I can tell this is the sort of thing that incites a lot of disagreement and is very much tangled up in other deep issues like the relationship between logically possible and metaphysically possible worlds and the question you raised of whether the fundamental laws are necessary or contingent.

    If logical possibility entails metaphysical possibility and the fundamental laws are contingent then it seems like Bayesian inferences about how reality works are surely valid. If those assumptions don’t hold then it seems murkier. Bayes might still work but I can see how people would disagree (or have their doubts).

    But at any rate, in my view the bottom line is this: if probabilistic Bayesian inferences about how reality works are indeed valid, then there simply is no alternative to strongly preferring theories of reality under which our circumstances are relatively common over theories of reality under which our circumstances are extremely rare.

    It depends how extremely rare of course. But in order to believe that we’re in a multiverse where habitable universes are one in a trillion, we’d have to be awfully sure that we’re not, for example, in an equally large multiverse where there was a good reason why habitable universes are the norm. After all you’d expect there’d be far more habitable universes to be found in places like that. (And of course the real numbers involved in fine-tuning discussions are much larger than one in a trillion.)

    I think the only ways to avoid this conclusion (if you were so inclined) would be
    A) Start with extremely strong prior belief that habitable universes are rare (I don’t think we have that which is why we’re considering this question in the first place)
    B) Discover some extremely strong evidence that habitable universes are rare (this is pretty much just a version of A)
    Or C) Deny that Bayesian reasoning works

    • conscienceandconsciousness May 3, 2018 at 1:04 pm #

      I’m not sure what reason one would have to think that Bayesian inferences don’t work when considering how reality works. It’s certainly a difficulty for the multiverse theorist having an account according to which our universe is not too uncommon (among universes with observers), but the theist would argue that the fine-tuning raises the probability that the laws were designed, which I think is a different consideration.

      • Evan May 4, 2018 at 6:20 pm #

        Interesting, thanks. Yes I’m inclined to trust it. But I’ve heard some people say it rubs their intuition wrong to apply probabilistic reasoning to a big claim (say, theism) before they’re confident it’s metaphysically possible. They say stuff like “It could be that things just don’t work that way, in which case it wouldn’t matter what the distribution of likely worlds is under that theory.”

        Actually thought that might be what you were going for when you mentioned necessity. Now I think you must have been going for something more subtle that I’m missing (and that led you to change your mind). I don’t think I follow what other connection there would be between the issue of necessity and the ability of multiverse theory to explain fine-tuning…

        In my head the essential Bayesian argument runs like this: fine-tuning suggests that under naturalism, habitable universes would be extremely unusual and thus presumably extremely rare. Under teleology, habitable universes would be the norm. The naturalist can posit the existence of extremely many universes, relying on the power of large numbers to guarantee the existence of at least one that’s habitable…

        But what’s to stop the teleologist from making the same move? If it’s easy to believe that there are extremely many universes, then the teleologist can posit the existence of extremely many universes all of which are intentionally habitable — essentially countering multiverse naturalism with multiverse teleology. And then we’re back to where we started, i.e. if we consider the distribution of all instances of habitable universes, we’d still be stuck with the conclusion that nearly all of them occur under teleology and far fewer occur under naturalism. The issue of necessity doesn’t seem to affect this argument.

        At the end of the day it seems that both naturalism and teleology have serious problems. Just can’t follow how necessity plus the multiverse can stop fine-tuning from being one of naturalism’s serious problems.

  5. Justin May 4, 2018 at 7:46 am #

    Hi Philip
    An interesting change of heart!

    Whilst I am not very up to date on multiverse theory, it seems to me that if there are independent grounds for inferring cosmopsychism, then agentive cosmospyschism may still be a more parsimonious explanation for fine-tuning than the multiverse.

    After all, subjectivity and purposive behaviour are closely aligned and if there is already a cosmic subject at hand, it does not seem that great a step to infer that it acts purposively William James’ evolutionary argument for the causal efficacy of consciousness adds further weight to the attribution of purposiveness to subjectivity (at the human scale at least, from which inferences about the universe could be made).

    Of course, this is far away from the world-view of contemporary science, but I think it could be rationally accommodated within a Whiteheadian cosmological perspective of “law as habit”.

    Admittedly, foresight on the scale of billions of years does seem so incredulous that I can see why the multiverse could be the preferred view even for a cosmopsychist.

    • Lee Roetcisoender May 4, 2018 at 2:09 pm #

      Folks, I get that the members of academia make their livings writing about what other academics of the past have stated, and then argue about it or come up with a different or unique spin on what has already been written. It seems that our current paradigm is bankrupt of anyone who is capable of coming up with an original idea. Sorry folks, this is not philosophy. What the bankrupt thinkers of our current paradigm are practicing is called philosophology, which is a regurgitation of the archaic thinking of the dark ages, all of which is being perpetuated by the exclusive, closed community of the Church of Reason called academia.

  6. Paul May 12, 2018 at 8:19 am #

    Maybe the universe is involved in a process that is similar to evolution. Universes evolve.

    • conscienceandconsciousness May 12, 2018 at 8:22 am #

      Cool idea. Problem is that physicists believe the constants have remained the same since the first second after the big bang.

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