Slides for Fining Tuning talk

Here are the slides for my recent talk at Ratio Christi, "Explanations for Fine Tuning":


Click on that link to find out about:

Part I: The physics of constants and units
Part II: How physicists diagnose fine-tuning
Part III: Some examples of fine tuned constants
Part IV: My own take on proposed explanations

Regrettably there was no recording, so those of you who weren't there won't get the benefit of the marathon Q&A session.  I try to put a lot of words on my slides, so hopefully most of them will be at least somewhat self-explanatory without me talking over them.  (I assumed the audience was already familiar with scientific notation...)

If you want to know more about the fine tuning of constants of Nature you could check out Luke Barnes' blog or order his book.  Or, if you are thirsting for a few more details about the "renormalization group flow" you could start with John Baez's explanation.

About Aron Wall

I am a Lecturer in Theoretical Physics at the University of Cambridge. Before that, I read Great Books at St. John's College (Santa Fe), got my physics Ph.D. from U Maryland, and did my postdocs at UC Santa Barbara, the Institute for Advanced Study in Princeton, and Stanford. The views expressed on this blog are my own, and should not be attributed to any of these fine institutions.
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72 Responses to Slides for Fining Tuning talk

  1. Kyle says:

    Do you have any thoughts on why the internet seems to suggest that most scientists such as yourself are hostile to religious ideas?

  2. Aron Wall says:

    Whaddya mean, the internet? The internet doesn't have opinions! Individuals have opinions, which they sometimes post to the internet. If you have some link to a specific poll, or an argument based on evidence, then we can discuss it. Otherwise, I don't see the point in refuting rumors.

    Note that there is a BIG difference between "not religious", and "hostile to religion" or "thinks that science and religion aren't compatible". Activists on both sides have a vested interest in conflating these, but the majority of scientists I meet fall into the first category only. And of course some of them are religious themselves, like me.

    In general I think that proxy fights over what most scientists think isn't probably very illuminating when it comes to resolving the underlying isuses. Academics have a particular culture, which leads to various cultural influences (e.g. most academics lean left on political issues.) As far as I can tell from my own limited personal experience, STEM types are actualy less hostile to religion than most of the humanities are, which suggests that science may not be the most important factor here. But most of them probably haven't even thought about it enough, for me to take their opinion seriously.

  3. kashyap vasavada says:

    Excellent lecture! I agree with most of it. But I have this question.
    As you say "Protons (and neutrons) are made of smaller particles called quarks, but the bulk of the proton mass comes from the strong force, not the quark masses." OK. Most physicists would agree that proton mass mainly comes from potential and kinetic energies of virtual quarks and gluons.
    However is there a contradiction in the following statement?
    "Requires fine tuning of light quark masses to 1% precision to get significant amounts of both carbon and oxygen! (Oberhummer, Csótó, & Schlattl 2001)". Do you believe these authors arguments? I would like to see a clarification.

  4. Aron Wall says:

    As I am sure you already know, there is a distinction between the fundamental strong force (which is carried by gluons and binds the quarks into baryons such as the proton & neutron, and mesons such as pions) and the residual nuclear strong force (which is carried by pions and binds the protons and neutrons together in the nucleus). The fundamental strong force has binding energies of order ~GeV, but the residual force involves much smaller binding energies of the order tens of MeV.

    Now in the triple alpha process, the initial three He-4 nuclei (\alpha particles) have the same total number of protons and neutrons as the final C-12 nucleus. So the GeV sized nucleon energies are not important. We are only diddling around with the binding energies, which are in the MeV range and therefore comparable to the mass of the up quark (m_u \sim 4 \mathrm{MeV}) and down quark (m_d \sim 9 \mathrm{MeV}).

    Also, the reason why the residual strong force is a short-range interaction is that the pion is a massive particle, which causes the force to fall off exponentially over distances of order the Compton wavelength of the pion. Now, if the up and down quarks were massless then it turns out there would be an exact symmetry which causes the pions to be massless. (Or at least the \pi^0 would be massless; I think the \pi^{\pm} would still have a tiny mass due to the electric charge difference between the u and d quarks.) In reality, the u and d are not massless, so the pion has a nonzero mass which scales roughly proportional to \sqrt{m_u + m_d} (times some constants having to do with other aspects of pion physics).

    Hence, because the quarks are pretty light, and because the square root function has a large slope near 0, it turns out that pion physics is surpisingly sensitive to changing the mass of the lightest quarks. I'm no expert in nuclear physics, and I have certainly not checked the triple \alpha calculations myself. But, for the reasons I have stated above, I can very well believe that it would depend quite significantly on the quark masses.

    Let me know if you would like me to explain any of this in more detail.

  5. kashyap vasavada says:

    Thanks for clarification. I sort of overextended in my mind the authors' nuclear argument to protons and neutrons. But again a great talk ! Worth using as talking points!

  6. Thank you for you fine tuning presentation. It goes deeper into the physics then I have ever seen before.

    [I added St. Steve's website to this comment---AW]

  7. kashyap vasavada says:

    Hi Aron,
    I read your excellent talk again. I am not sure where this number (C.C. scales 10^(-5) ) comes from. Is that from CMB data or the experimental measurement of accelerating expansion? Do you have a handy reference? Thanks.

  8. Aron Wall says:

    So as you can see from my slides, there's two different length scales associated with the cosmological constant.

    Without the Cosmological Constant, Einstein's equation is

    R_{ab} - (1/2)g_{ab} R = 8\pi G\,T_{ab},

    where R_{ab} is the curvature scale of matter (which has dimensions \mathrm{length}^{-2}) and T_{ab} is the stress energy tensor (which has dimensions \mathrm{energy} / \mathrm{length}^{3} = \mathrm{length}^{-4} in units where c = \hbar = 1).

    We can choose to think of the C.C. in 2 different ways, either as an extra curvature term g_{ab} \Lambda added to the left-hand side, or you can think about the stress tensor T_{ab} = \rho g_{ab} which you would have to add to the right-hand side in order to produce that curvature gravitationally. In Planck units (where we additionally set G = 1) these two ways of thinking about the C.C. both give it the same value of approximately 10^{-122}. However, because curvature has units of \mathrm{length}^{-2} while energy density has units of \mathrm{length}^{-4}, the length scales are radically different. The C.C. energy scale is at the geometrical mean between the Planck scale and the C.C. curvature scale.

    The length scale associated with the energy density (corresponding to the CAUSE of the C.C.) is around 10^{-5} \mathrm{meters}, while the length scale associated with the curvature (corresponding to the EFFECT of the C.C) is at the scale of billions of lightyears. This is one reaosn why it is not plausible to solve the C.C. by a "feedback mechanism" whereby some field notices that the curvature is nonzero and dynamically adjusts its energy density to compensate. The length scales involved are too disparate.

    Now only the curvature effects of the C.C. are actually measurable. A constant energy density is not measurable in QFT aside from its gravitational effects (although it is an interesting coincidince that its scale is roughly the same as that of the neutrino masses...)

    Rather, it is the curvature scale which is measurable. We seem to get the same value by looking at either CMB radiation (where we are testing the prediction that the total energy density \Omega of the universe is enough to make it flat) and by looking at distant supernova (where we are testing the prediction that a positive C.C. causes the expansion of the universe to accelerate). I'm not sure of a good review for the observational evidence; I've mostly learned this stuff through talks and by osmosis, but two key words are "Concordance Cosmology" and "Lambda-CDM model".

  9. Mactoul says:

    That "God did it" is merely a way of saying "it is inexplicable".
    The cosmologists, ever since Big Bang theory, have managed to create immense confusion esp among the theists. Consider how Big Bang is explained at Wikipedia to what a typical Internet theist believes.
    "The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution."
    "If the known laws of physics are extrapolated to the highest density regime, the result is a singularity which is typically associated with the Big Bang. Detailed measurements of the expansion rate of the universe place this moment at approximately 13.8 billion years ago, which is thus considered the age of the universe."

    For the Internet theist this amounts to saying that Big Bang theory describes scientifically the creation ex nihilo of the universe by God.

  10. Josh says:

    Hi Aron,

    Thought you might find this project interesting:

    "Our goal is to consolidate the idea of fine-tuning across disciplines such as biology, chemistry, and physics. Fine-tuning is often deemed a fact and used to reach grandiose metaphysical conclusions by philosophers, theologians, and even physicists, without a proper understanding of the underlying assumptions entailed by these arguments. As a consequence the physical and philosophical literature on this subject are rather confusing, leading to esoteric topics such as Boltzmann Brains. We intend to present a comprehensive review of the physics used for deriving fine-tuning arguments, scrutinising the current ones and uncovering new examples, thereby providing a solid foundation for future efforts to interpret this fascinating facet of Nature.

    We will produce a field-manual for fine-tuning and create an accompanying interactive website targeted at a general audience. Further details of these subprojects will be announced here in the future."

  11. Aron Wall says:

    Thanks for the link, Josh. It looks like they are still in the early stages, but I will be interested to see how it turns out.

  12. adv says:

    Hello Aron,

    Your blogs are very fascinating. I was discussing this with my fellow colleague and he presented with a question. Why is the universe so vast unnecessarily, if there was an intelligent agent behind all this fine tuning, why not just the planets or solar system alone. He also bought a topic to tuning the dials to get the precision correct by an intelligent being doesn't sit well. So his claim is that all this is random. Is there a counter argument for this handled some where?

  13. Mark Biggar says:


    This (a large universe) is also a fine tuning issue. To create the larger elements you need a few generations of stars, so it can be argued that you need at least a galaxy. Galaxy formation may well require something like inflation which seems to produce a large universe. So everything needs to be fine tuned to get a large universe just like we see.

  14. adv says:

    Hello Mark

    Thanks for the reply. Yes exactly the argument that is presented, so my fellow atheist argues that if an intelligent agent was capable of fine tuning, why not fine tune with a small universe or even have one planet with life and that's it (if universe was fine tuned for life). Obviously the intelligent agent is beyond the laws of physics.Why so much of stars, galaxies. If life is fine tuned for the universe, then this has just to be a chance among the other multiverse/megaverse scenarios. So basically saying that there is no God behind fine tuning, as it is too complex and unwanted. This is where I didn't have a reply. Now even I am puzzled by this.

  15. mom the linguist says:

    Of course God cares about life, but probably that's not the only thing he cares about. There might be other purposes for the universe than just us humans. I'm reminded of the biologist that said the one thing we could be certain of about God from studying nature, was that he was fond of beetles (I believe there are more beetles BY WEIGHT than there are humans)! I expect God thinks the universe is beautiful, as do most of us.

    Leaving out the possibility that there might be other life, even intelligent life out there, with which God would be doubtless also concerned.

  16. adv says:

    Hello Mom

    Thanks for the reply. Yes many beetles, especially in my garden. I kind of use the similar argument and in response all I get is that we are just avoiding the correct answers, and we don't have an answer that is strong. They seem to think the multiverse concept is strong. Then my question is why a multiverse. Another confusion I have isn't multiverse the end of science. I am not a physics expert by any means but, if the think that our universe is just one that has such and such properties then everything can be because of this. That said why this complexity, spiritually I have always believed in simplicity.

  17. Aron Wall says:

    I've been pretty busy recently, but I wanted to say something about your comment.

    When Theists discuss fine-tuning, we are presupposing that God chose one particular set of laws of physics to govern the universe. Since God can do miracles, he could have chosen to create the solar system supernaturally, instead he chose elegant and consistent laws of Nature which give rise to things like solar systems automatically.

    Now as my Uncle Mark correctly pointed out, there are no plausible laws of Nature that give rise to just the solar system without the rest of the galaxy. The rest of the galaxy is needed to get heavy elements.

    And as my Mom correctly pointed out, theologically there is no reason to believe that God cares only about life. That is not part of the fine-tuning argument, and really it seems absurd on its face. If human beings take pleasure in thinking about the vastness of the universe and all its amazing structures, why should God not also do so? Indeed, since his wisdom is vast beyond our imagining, he probably created them partly for reasons that are entirely beyond our understanding.

    Perhaps you could have your colleague read "Dogma and the Universe", an essay in St. Lewis' collection "God in the Dock". In it he says:

    And this drives me to say yet again that we are hard to please. If the world in which we found ourselves were not vast and strange enough to give us Pascal’s terror, what poor creatures we should be! Being what we are, rational but also animate, amphibians who start from the world of sense and proceed through myth and metaphor to the world of spirit, I do not see how we could have come to know the greatness of God without that hint furnished by the greatness of the material universe. Once again, what sort of universe do we demand? If it were small enough to be cozy, it would not be big enough to be sublime. If it is large enough for us to stretch our spiritual limbs in, it must be large enough to baffle us. Cramped or terrified, we must, in any conceivable world, be one or the other. I prefer terror. I should be suffocated in a universe that I could see to the end of. Have you never, when walking in a wood, turned back deliberately for fear you should come out at the other side and thus make it ever after in your imagination a mere beggarly strip of trees?

    I hope you do not think I am suggesting that God made the spiral nebulae solely or chiefly in order to give me the experience of awe and bewilderment. I have not the faintest idea why He made them; on the whole, I think it would be rather surprising if I had. As far as I understand the latter, Christianity is not wedded to an anthropocentric view of the universe as a whole. The first chapters of Genesis, no doubt, give the story of creation in the form of a folk-tale — a fact recognized as early as the time of St Jerome — and if you take them alone you might get that impression. But it is not confirmed by the Bible as a whole. There are few places in literature where we are more sternly warned against making man the measure of all things than in the Book of Job: ‘Canst thou draw out leviathan with an hook? Will he make a covenant with thee? wilt thou take him for a servant? Shall not one be cast down even at the sight of him?’

    In St Paul, the powers of the skies seem usually to be hostile to man. It is, of course, the essence of Christianity that God loves man and for his sake became man and died. But that does not prove that man is the sole end of nature. In the parable, it was the one lost sheep that the shepherd went in search of: it was not the only sheep in the flock, and we are not told that it was the most valuable — save in so far as the most desperately in need has, while the need lasts, a peculiar value in the eyes of Love. The doctrine of the Incarnation would conflict with what we know of this vast universe only if we knew also that there were other rational species in it who had, like us, fallen, and who needed redemption in the same mode, and that they had not been vouchsafed it. But we know none of these things. It may be full of life that needs no redemption. It may be full of life that has been redeemed. It may be full of things quite other than life which satisfy the Divine Wisdom in fashions one cannot conceive. We are in no position to draw up maps of God’s psychology, and prescribe limits to His interests. We would not do so even for a man whom we knew to be greater than ourselves. The doctrines that God is love and that He delights in men, are positive doctrines, not limiting doctrines. He is not less than this. What more He may be, we do not know; we know only that He must be more than we can conceive. It is to be expected that His creation should be, in the main, unintelligible to us.

    I have no idea what your friend meant by "tuning the dials to get the precision correct by an intelligent being doesn't sit well". Doesn't sit well with what? And certainly the universe isn't just random, since probability 10^{-120} events don't just happen by chance.

    Unless by "random" you meant the multiverse. Here we have the grave difficulty that nobody really has a good way of doing probability theory in the multiverse. But when you ask if this would be the "end of science" well I think it depends on what kind of multiverse you are talking about. A multiverse in which literally every logically possible thing exists, would predict everything equally and therefore nothing. But if we are talking about e.g. the multiverse of string theory, then there is some specific set of allowed possible universes which are allowed given the rules of string theory, and there are certain features that tend to be common to all of them.

  18. Scott Church says:

    Hello adv,

    There isn't much I can add to the wonderful insights of St. Aron and St. Lewis. But if I may, let me share one observation with you that although pedestrian by comparison, is worth noting.

    Essentially, your colleague's argument boils down to, "If I were God, this is how I would've done it...!" Apart from the breathtaking hubris of imagining ourselves qualified to tell God how to do His job, it's demonstrably fallacious. It's a common argument these days, and depending on how it's framed, it usually ends up being some combination of Nirvana, Moving the Goalposts, or Argument from Consequences fallacies. It's popular for the same reason Monday morning quarterbacking is... it's a conversation stopper that gives the one wielding it a get-out-of-jail-free card regardless of any evidence presented.

    As the Garden of Eden made abundantly clear, it's in our nature to imagine our pay grade to be considerably higher than it actually is. J.B.S. Haldane once said,

    "My own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose."

    Confronted with such a universe--one that for all its resplendent beauty is often inscrutable and distastefully resistant to our vanity, get-out-of-jail-free cards can be awfully inviting. As Lewis so eloquently pointed out, this is why we were given the book of Job.

    Best. :-)

  19. Aron Wall says:

    Thanks Scott,

    Interesting you should mention Haldane, because another quip of his was referenced above: supposedly some theologians asked him what could be deduced about the Creator from his creation, and he said "An inordinate fondness for beetles".

  20. Scott Church says:

    Wow... I was wondering where that reference to beetles came from. That was Haldane...? How coincidental, and cool is that?! Thanks Aron! :-)

  21. adv says:

    Scott, Aron many thanks for you time. Many thanks for the reply. My colleague is part of a free thinking movement. But somehow they seem to be following a set of views, so not sure if they are really free thinking. I will present some arguments given to me, more than happy to replies or to posts if already discussed. Some already answered by you.
    # The idea about dials tuned by God - the argument is that constants are so large in numbers and fine tuned that it sound funny that God had to tune the numbers like a radio dial to get them right for life. It sit more comfortable with a lucky dip from a set of possibilities, multiverse with infinite combination, I think this is what was coined as multiverse. Also if God was so powerful then what is the need for this complexity. If some where not for our understanding, then God is being partial and not loving his creations. An art is more enjoyed when understood better.

    # I actually don't know which universe are they referring to, megaverse, multiverse, but the argument is that among the infinite number of universe, we just happen to occupy a sweet spot which was ok for life, not vice versa . There maybe other life too, but then we can't see them as they are far away. Again if created by God why this separation. I replied even with seven continents humans are fighting, think about other worlds :), so it makes sense to be separated.

    # then comes Hawkings comment about no need for God as some M theory or whatever theory proves Universes pop out of nothing. Not a physics expert so kept quite. Tried to read up on these, complicated to me, but seems to have a lot gravity among scientific crowd. I am reading your post on HH no boundary stuff.

    #Burden is on us to prove God as science can't explain a non existent thing.

  22. Aron Wall says:


    1) "It sounds funny" is not really an argument; all it means is that the speaker finds the idea quirky but any explanation of how life came into existence is likely to sound funny to some people. Darwinian evolution sounds funny to many people, that doesn't make it not true.

    Presumably it is a logically necessary truth that if God wanted to make life using laws of physics similar to our own, that only some sets of constants of Nature would allow habitable planets to exist through natural processes. (I am not going to say that the first life itself appeared by a natural process, since nobody yet understands the process of abiogenesis. Maybe it was a miracle, maybe not.)

    2) Well you don't have to be a physics expert to see that Hawking is venturing into philosophy, not just physics! Feel free to point them to my blog post on Fuzzing into Existence if you think that would help.

    It is true that M theory is taken very seriously as an idea by string theorists, and for good reasons, but one should bear in mind that there is no direct experimental confirmation of string theory/M-theory, so while it might turn out to be true is should always be presented to nonscientists as speculative!

  23. Scott Church says:

    Hello adv,

    The pleasure is mine! And thank you for the enlightening clarification of your colleague's arguments and his movement. From the looks of it, all of them are commonplace these days in secular circles, and none stand up to scrutiny. To wit, here are a few more thoughts (as always Aron, feel free to correct me if I miss the mark on anything!)...

    1) The term fine tuning refers strictly to the fact that many fundamental parameters happen to fall within narrow ranges consistent with life even though no physics constrains them to. To that extent, it's just a metaphor borrowed from something familiar to our experience... not a claim that God literally had to "dial in" a bunch of parameters until He hit some anthropic sweet spot. It's only "funny [sounding]" if you take it literally, which your colleague appears to be doing. And as St. Aron pointed out, it isn't an argument at all--it's yet another get-out-of-jail-free card.

    Notice how the game is played... Show him a universe where the range of anthropically allowed values for these parameters is large and he'll say, "See...? There is no fine tuning...!" Show him one like ours, and you'll be told it "sounds funny" that God had to tune a bunch of parameters to accommodate our existence... Heads he wins, tails you lose. One encounters this sort of thing again and again in the arguments of so-called "free" thinkers. Most are only free because they aren't constrained by any reasonable standards of proof. It would be interesting to hear what, if anything, actually would convince him. As for his comments about the "need for this complexity," That's just another example of someone well below God's pay grade presuming to tell Him how to do His job.

    2) As St. Aron also said, his string theory multiverse alternative is speculative... but that's hardly the word for it. To give you an idea of just how speculative it is, consider that string theory has been around in one form or another since the early 70's, and M theory since 1995. In the 40+ years since its inception, it's generated more than 50,000 published papers but has yet to make a single testable prediction.

    Pause for a moment and let that sink in... 40+ years, and 50,000 peer-reviewed papers... and not one single testable prediction of any kind!

    A few of its more devoted proponents have claimed that it has, but only by loosening the definition of "prediction" to where Ouija boards would pass for controlled experimentation. It's also worth noting that this situation has no historical precedent. Prior to string theory post-Enlightenment physics has never gone for more than a decade or so before any theory was experimentally verified or falsified to at least some extent. It's gotten to a point where an increasing number of physicists are actually claiming that falsifiable predictions no longer have a place in science, and the situation is serious enough that many philosophers of science are claiming that science itself is in danger of becoming marginalized. Not surprisingly, apart from a few notable exceptions, the large majority of those defending this viewpoint (which has come to be known as Post-Empiricism) are atheists and free thinkers like your colleague. And there you have it... For centuries we've been told that God is unscientific because He "cannot be proven..." Now we're being told that science needs to shed the shackles of proof. How ironic is that...? :-)

    Furthermore, M theory isn't really a "theory" at all per se. It's a theoretical framework that constrains the form any potentially viable string theory can assume. The number of possibilities is mind-boggling. Of the countless options that have been investigated so far, only a handful have even generated exact solutions, and those are only valid for toy universes that look nothing like the one we actually live in. Even if we let all of that slide, the multiverse is nothing more than an academic exercise without a physical way to actually generate one. To date, there is only one such option that's even remotely viable--eternal, or "chaotic" inflation. And of late it has been running into a number of problems of its own, not the least of which are the lower boundary constraints on imposed on primordial inflationary gravitational waves by the recent BICEP2 results (which ironically, were originally hailed as a "smoking gun" for inflation before they were properly vetted).

    The bottom line is that your colleague's "more comfortable" alternative takes the phrase Hail Mary to a whole new and terrifying level. I suspect that his comfort with it has less to do with Occam's Razor or science than what his free thinking movement deems politically correct.

    3) With all due respect for Hawking, his claim that Universes can "pop out of nothing" isn't merely questionable... it's a train wreck. For starters, there's the physics involved. I won't get into the subtleties of it here, but suffice to say that energy density is frame-dependent, and only conserved locally. For the universe as a whole it is neither well-defined, nor conserved. It's possible to derive a zero energy universe from Newtonian mechanics, but that analysis requires the Poisson equation to be well-defined for an infinite universe, and it isn't. There is one, and only one condition under which the energy of the universe could be zero, and that is if it's closed. But a closed universe is also one of finite size... and thus, a bullet in the temple for your colleague's "comfortable infinite combinations" multiverse, which requires a chaotic inflation scenario unfolding in a single, simply-connected space-time that in this case would have to be past-eternal, raising a whole host of other problems I won't get into here, but that St. Aron has dealt with at length. Out of the frying pan and into the fine tuning fire. St. Aron deals with all this at length his wonderful essay Did the Universe Begin? VII: More about Zero Energy.

    But the physics problems are child's play compared to the metaphysical ones. The whole idea of a universe popping out of "Nothing" presumes that non-being is a thing with properties like energy. It's one thing to say that Nothing has no energy... It's another thing altogether to say that Nothing has an energy, and that energy is equal to zero--in other words, nothing is a thing with an energy so it's something even though it's nothing. The former makes sense. The latter is the sort of thing one would expect from a Vegas showgirl after six martinis and a fistful of Quaaludes. :-)

    4) St. Aron is, of course, right about Hawking venturing into philosophy. This demonstrates a fact that's almost universally overlooked these days--everyone engages in metaphysics... including scientists like Hawking who imagine themselves to be above it. Ultimately, there are two types of people in the world--those who've learned some philosophy and do so consciously, and those who do so unconsciously, and therefore badly. Like many atheist scientists these days, Hawking is well within the ranks of the latter. To wit, in The Universe in a Nutshell he said that in his view science should be based on "the positivist approach put forward by Karl Popper and others..." blissfully unaware that Popper was a well-known critic of positivism, and even coined the term "Popper Legend" to describe those who considered him part of that school of thought as Hawking does.

    5) Last, but not least, is the mother of all get-out-of-jail-free cards... your colleague's claim that the burden of proof is on us because "science can't explain a non existent thing." Not only does that beg the question in his favor, it too is demonstrably fallacious on multiple levels. The assumption being made here is that God is "a god." That is, one particular instantiation of a class of things called "gods" that are thinking, changing, history-bound beings like us (note the plural and verb forms) except incorporeal and far greater. We then (so the argument goes) postulate the miraculous interventions of this "god" (or "gods") in nature to explain what we cannot be accounted for scientifically and take these "unexplainables" to be evidence of his existence. There are so many things wrong with this it's difficult to know where to begin. But for this discussion the key point is that per classical theism, God is not "a god," but the eternal and omnipresent (beyond space and time), omnipotent, omniscient, ground of all being and personhood--the creator and sustainer of all else that is (note the lack of a "god" or "person" instantiation and plural or verb forms). To call Him an instantiation of some general class of things called "gods" is a category error. There can only be one ground of all being, and if it's not God then it has to be the physical universe. Thus, one cannot reject God without embracing his only viable alternative--a comprehensive philosophy of Materialism. Both require a rigorously thought-out defense... which is precisely what virtually every atheist thinker of any repute in history has devoted his/her life to producing. Arguments like this one are only taken seriously by new atheists, few of whom have any real training in philosophy of religion. For more on the problems with it you can check out an essay of my own on new atheism conversation stoppers (specifically, point 5).

    Once again, I hope this helps. Best!

  24. TY says:


    The comments from Aron & Scott represent a full scientific arsenal of arguments to counter your colleagues'. I have s simple suggestion: invite the person to read these posts and if he/she is so convinced of his/her position, he/she ought have the intellectual courage to comment back in this post. I just fear that some of the subtleties might get lost in your trying to understand the physics to begin with, and then trying to convince through the discussion, which becomes harder and perhaps futile. !

  25. Mactoul says:

    Scott church,
    "The term fine tuning refers strictly to the fact that many fundamental parameters happen to fall within narrow ranges consistent with life even though no physics constrains them to"

    So fine-tuning is an argument in biology? The part about "no physics constrains them to" is strange for it is not obvious how a physics theory would constrain its own parameters. Logically, any physics theory has some parameters that are set either by experiments or by an underlying theory.

    For this to jump to "God did it" is unjustified from either physics or biology or any other science. No science could possibly have this statement "God did it". All the science can say that this thing is inexplicable.

  26. adv says:

    Aron, Scott, once again many thanks for your time to answer my queries. I have started to read the links in the reply. Scott your comment on the fine tuning, either way you toss I lose, is great LOL. But then I have read the common free thinking comments that these theories are the best at this time and will only get better as technology and time goes. I have started to read the links provided by you guys. Arno, so if M theory is taken seriously and proved, will that eliminate God? Because based on M theory there are multiple universes right? But still who created the membrane is the question?

    @TY I have given my friend the link to the discussion hopefully they read it. I tried to kind of reflect things from our discussion, but not very effective. But these questions were also for my understanding too. So I was also interested to get my confusion cleared as I am no physics expert. Hope that's not a bad thing :).

  27. adv says:

    Scott, sorry missed out on one thing. "... For centuries we've been told that God is unscientific because He "cannot be proven..." Now we're being told that science needs to shed the shackles of proof. How ironic is that...? :-)" isn't that because we believe in God and don't agree to them? So their only way of language is Science so they are asking for proof. Sorry if I have understood your comments wrong

  28. Scott Church says:

    Hello Mactoul. To your claims above...

    "So fine-tuning is an argument in biology?"

    No. Fine tuning has nothing whatsoever to do with biology or where/how life could arise in a universe like ours. What makes the parameters it's concerned with anthropic is the fact that they constrain the existence of universes where any sort of life would be possible. To wit, take the cosmological constant, which among other things determines the expansion rate of the universe post-big bang. A slight variation of it in one direction results in a universe that collapses back to a singularity within a few minutes of the big bang, before its temperature has even dropped below that of a nuclear fireball. A similar variation in the other direction and you have a hyper-inflating deSitter universe with no more than a dozen subatomic particles per cubic light year. Likewise, vary the fine structure constant by a factor of two to four and you have one where stable chemistry isn't possible--no atoms or molecules, just subatomic particles, most of which will decay into other particles if a matter of minutes. Never mind biology, carbon-based or otherwise... If you can think of a way that life by any<reasonable definition whatsoever could possibly exist in universes like these, I'm all ears.

    To some extent these impacts can be offset by adjustments in other parameters. Variations in the fine structure constant can be mitigated somewhat by changes in the strong force coupling constant for instance. There are no serious investigations of fine tuning that don't take multiple parameter variances into account, but these only get you so far, and in every case lead to even more damaging instabilities elsewhere. Furthermore, to the best of our knowledge a number of these parameters are entirely stand-alone. The cosmological constant is a case in point. Not only do we have no idea what might set its value (if anything does), nothing we know about the universe today even remotely suggests how it might be related to other parameters. Yet it is anthropically constrained to one part in 10^{122}... that is, to one part in a million trillion trillion trillion times the number of subatomic particles in the visible universe. Yet we have no more reason to believe it's observed value to be the result of underlying physics than we do to think that "God just did it" that way. Put your faith in the former if you like, but outside of the new atheist community you'll be hard-pressed to find anyone who would bet a dollar bill on odds like those, much less their worldview.

    "The part about 'no physics constrains them to' is strange for it is not obvious how a physics theory would constrain its own parameters. Logically, any physics theory has some parameters that are set either by experiments or by an underlying theory."

    Go back and read the statement you just quoted again... this time, carefully. I didn't say that any "physics theory [constrains] its own parameters." I said that no physics constrains the fundamental ones.... and physics is the sum totality of our underlying theories and experiments. There are 26 fundamental constants. For these, fundamentalmeans there is no known physics from which their values can be derived, nor any indication of how they might even be related to each other. As far as we currently know, their experimentally measured values are brute facts. That situation may or may not change with further advances, but until it does it remains possible that they just are what they are.

    "For this to jump to 'God did it' is unjustified from either physics or biology or any other science. No science could possibly have this statement 'God did it'. All the science can say [sic] that this thing is inexplicable."

    Again, go back and reread my statements and St. Aron's carefully. No one is saying that fine tuning = "God did it." What we are saying is that "this thing is [scientifically] inexplicable" is not equal to "God didn't do it." There's a difference.

    We expand our knowledge of the physical universe by discovering how current theories emerge from ever deepening theories underlying them, and in the process how some, or all of the current "fundamental" parameters are explained. This is how science has always worked, and how it always will work. But at some point we'll reach bedrock reality--the level at which there is no deeper explanation, but that which simply is. An infinite regress or circular chain of causes does nothing to resolve this. If/when that comes to pass this bedrock theory will have parameters of its own that will raise still more questions, and science will press on because we can never know for certain that we're there. Now by definition, the God of classical theism is the ground of all being, and this is a formally derived metaphysical conclusion, not a scientific one (Davies, 2004; Feser, 2008; 2009; 2014). As such, if we are at bedrock reality then "God did it" will in fact be the correct answer. In this case science will press on, but won't find any deeper levels. Since this is, and always will be, a possibility (indeed, given the unprecedented 40+ years we've now gone without improving on the standard model, some have argued that it may well have happened already), it follows directly and necessarily that, "God did it" is, and always will be, a possibility.

    There is one, and only one way around this, and that is to adopt Scientism, which claims not only that the scientific method is our most authoritative and reliable source of epistemic knowledge (Positivism), but that there literally is no such thing as truth apart from it. By definition, science deals only with the observable, testable material world. Scientism makes a metaphysic of this, and as such argues in a circle. The end result is yet another example of something that is becoming increasingly common in atheistic circles these days... a rational, and metaphysical train wreck.


    Davies, B. (2004). An Introduction to the Philosophy of Religion. Oxford University Press; 3 edition. ISBN-10: 0199263477; ISBN-13: 978-0199263479. Available online at Accessed Sept. 28, 2016.

    Feser, E. (2008). The last superstition: A refutation of the new Atheism. St Augustine Press Inc. Available online at Accessed Sept. 28, 2016.

    Feser, E. (2009). Aquinas: a beginner's guide. One World Publications. Available online at Accessed Sept. 28, 2016.

    Feser, E. (2014). Scholastic Metaphysics. Editions Scholasticae. ISBN-10: 3868385444; ISBN-13: 978-3868385441. Available online at Accessed Sept. 28, 2016.

  29. Scott Church says:

    Hello adv,

    In answer to your question, I won't get into the messy details of it here, but the suffice to say that the reason many atheists are pushing Post-Empiricism is that the one, and only alternative they have to account for the fine tuning issues raised in St. Aron's talk (and my response to Mactoul above) is the so-called "string landscape"and an eternal inflation scenario to create it. And not only is it untestable, it never will be testable... ever. The distance/energy scale on which it's structure becomes visible will be that of the "compactification" scale of its higher dimensions, which is comparable to the Planck scale (i.e. 10^{-35} m). Probing that scale requires that we build a Large Hadron Collider the diameter of the solar system (with all the attendant luminosity problems solved) and operate it for an extended period. Don't hold your breath... Faced with a worldview that pits God against "science," and the latter requires testable predictions, the only way to avoid confronting your Creator is to do exactly what they're now doing--redefine "science" so that testable predictions aren't part of it... and if anyone asks how this is any different from blind faith, change the subject. :-)

    Other than that, the whole shtick of pitting our faith in God against scientific "proof" (which no longer involves predictions validated by factual data) is a textbook example of a "god-of-the-gaps" fallacy. Again, I won't delve into it today, but suffice to say there are so many things wrong with this it's difficult to know where to begin. But in addition to essay linked, any of the sources I cited to Mactoul above would be a great place to start. Best. :-)

  30. TY says:

    That's good to become familiarised with the physics, at least in a general sense. You are not alone: I am not a physicist but I've read up quite a bit from many sources, watched U-Tube, read all of Prof. Aron's posts, asked questions from physicists, to become "literate" in the cosmologically related area of the discipline. The literacy helps to spot when some physicists are making outlandish and speculative claims, and when wannabe physicists are just talking nonsense. For example, on the former, you don't have to have the expertise and brains of St Aron to know that some of the things Stephen Hawking, brilliant man though he is, wrote some nonsense in his second book, the Grand Design.

    Admirable effort on your part!

  31. TY says:

    “For this to jump to "God did it" is unjustified from either physics or biology or any other science. No science could possibly have this statement "God did it". All the science can say that this thing is inexplicable.”

    "Inexplicable" yes, by the known laws of nature; that said, science is unqualified to claim that “inexplicable” means “no explanation exists”. There is the supernatural to think about.

    I’m not suggesting anything absurd as God of the gaps (that Scott alludes to), and I’m not claiming that fine tuning “proves” God exists, but is one of the many evidences pointing to a creator God. That's the essential conclusion of Prof Aron's presentation in this post.

  32. Mactoul says:

    Scott church,
    You have explained very clearly but I still have some reservations.
    1) Science can't say whether it has reached "bedrock reality" or not.
    2) "if we are at bedrock reality then "God did it" will in fact be the correct answer."

    One, "God did it" will not be an answer given by science for science can never make pronouncements about God.
    Two, "God did it" is the answer we may give right now without bothering about bedrock reality. Why does proton weigh this much? Because God made it so. however, this answer belongs to theology rather than physics.
    Three, "Theologically, the notion of "God did it" is complex. In one sense, God does everything, in another sense God does some things in a special way i,e. supernaturally and other things in another way i.e. naturally. One may validly ask what precisely do you mean by "God did it". Does it mean anything other than "it is inexplicable (within physics)" or "it is a brute fact".
    That is, is the proper conclusion "God must have done it (for we can't make physics go deeper)" rather than the positive statement "God did it"?

  33. Scott Church says:

    Hi Mactoul,

    Regarding your last three points, you won't get any argument from me. :-) To wit...

    1) "'God did it' will not be an answer given by science for science can never make pronouncements about God."

    Absolutely. This is why Scientism is circular... it begs the question against God by declaring natural science to be the sole arbiter of all truth, including statements regarding the supernatural which is clearly beyond its purvey.

    2) "'God did it' is the answer we may give right now without bothering about bedrock reality. Why does proton weigh this much? Because God made it so. However, this answer belongs to theology rather than physics."

    Again, absolutely. But needless to say, if/when we do arrive at "bedrock reality" there aren't going to be signs greeting us... "Welcome to Brute Fact-Ville. Visitor parking on the left..." As such, if we start answering every question with "Because God made it so..." we would effectively shut science down. If we're to make any progress we must assume that we aren't there yet and press on. The best we'll ever be able to say is that the longer we go without making progress toward deeper theories, the more confident we can be that we are. Given that 40+ years physics haven't taken us beyond the standard model, we might be inclined to say that bedrock reality may have been reached. If nothing has changed 50 years from now, our grandchildren might be willing to bet a $10 bill on that. Three centuries from now, when far more of the universe and its distance/energy scales have been explored, if we still haven't gone beyond it we might bet a paycheck. But we'll never be able to prove that we've arrived. "God did it" will always be a possibility, but never a certainty, and not one that science itself will ultimately be able to address.

    The problem with the standard atheistic responses to (currently) inexplicable fine tuning isn't that anyone considers it synonymous with "God did it." That's just a god-of-the-gaps fallacy and no one of any repute is making such a claim. Rather, it's that because they're beginning from a position of Scientism, they're taking "God didn't do it" as the de-facto answer regardless of whether it's inexplicable or not. The correct answer is that while science opens many windows into the nature of how things are, when the end of science has been reached, the only explanation open to us will be the theological one. If we're theists, it will be "Praise His name...!" If not, it'll be "Because Mommy said so, that's why..."

    And there you have it... scientists who claim to be free of metaphysics are in fact practicing it. In the words of the philosopher Alfred North Whitehead,

    "Scientists animated by the purpose of proving that they are purposeless constitute an interesting subject for study."

    True that! :-)

    3) "Theologically, the notion of 'God did it' is complex. In one sense, God does everything, in another sense God does some things in a special way i.e. supernaturally and other things in another way i.e. naturally."

    Yes, and this is why god-of-the-gaps argument fail. C.S. Lewis once asked whether Gulliver was shipwrecked because a storm dealt more of a beating to his ship than it was structurally able to withstand, or because Swift wanted him to be to further his story. Either... both... it doesn't matter. Once we realize that Swift is the author of the universe his story takes place in, including the laws that hold it together, we see that both explanations are entirely valid. They account for the same events from different perspectives... "scientific," and "theological." The idea of "bedrock reality" is not one we derive from scientific considerations, but metaphysical ones--specifically the cosmological argument in its original and proper form rather than its post-Enlightenment knockoffs. At bedrock reality we say "God did it" (or an equivalent statement) not because it's a viable scientific answer, nor because it's an alternative to one (it's neither). We say it because we've reached the end of science, and the theological perspective is the only place from which we can speak.

    4) "[Is] the proper conclusion 'God must have done it (for we can't make physics go deeper)' rather than the positive statement 'God did it'?"

    Well said Sir! Actually, I've only been using the phrase "God did it" because others I've been responding to here, and in other forums were. Yours is much better... I may even shamelessly borrow it from time to time! :-)

    One further thought on all this... IMHO we often get into trouble with questions like these because we approach them as matters requiring proof rather than understanding (which interestingly, many critics of religion claim they don't do regarding science). Proof (at least in the usual sense of that term) is something we achieve in formal mathematics and logic. Empirical claims of the sort science deals with are another matter. On this turf, "proof" is reserved only for the most immediate claims with the most overwhelming evidence... or as one would say in a courtroom, evidence that is "beyond a reasonable doubt." This rules out many, if not most of the questions that concern scientists and theologians. IMHO, these questions are best addressed not with the expectation of "proof," but by inference to the best explanation. God and Materialism both begin with observation and experience, and reason to their conclusions via different paths. What we should be concerned with is: Which viewpoint provides the most robust and broadly explanatory account of all our experience, and is least subject to Occam's Razor? This give us more rational flexibility to speak to what would otherwise be intractable disagreements which cannot be "proven" in any practical sense. But it has an additional benefit that is sorely needed these days... it forces all of us, theist and atheist alike, to confront the fact that our understanding of best has as much to do with our own beliefs, values, and human stories as it does what we take to be "evidence." Most theists would be quick to admit as much. But in my experience at least, few atheists would. I can count on less than one hand the number of atheists I've met in my adult life who didn't consider their views of God and religion to be synonymous with "reason" and "science," and were willing to listen to another viewpoint to understand it, rather than simply reply to it, and "correct" it.


  34. Mactoul says:

    Scott church,
    Thanks for a considered reply. We are, it seems, in general agreement.
    I found an interesting quote on scientific cosmologists and their penchant for creating entire universes out of nothing:
    Application of quantum mechanics by scientific cosmologists rest on a non-sequitur, voiced by Heisenberg as early as 1927, that an interaction that can not be measured exactly, can not take place exactly. This non-sequitur is the jump from the operational to the ontological-a fateful jump indeed, because if its bearing is extended from from the level of alpha-particle emission from the radioactive atoms to the universe itself, it enables the physicist to create the entire universe itself out of nothing by his mere fiat.
    Stanley Jaki, God and the Cosmologists (1989).

  35. Aron Wall says:

    Mactoul & Scott,
    You two may be in agreement with each other, but I think I am not.

    As I've said before, I do not believe that "God of the Gaps" arguments are necessarily fallacious, although of course some arguments in that class are a lot more credible than others.

    Scott, you wrote:

    No one is saying that fine tuning = "God did it."

    I appreciate your attempts to protect my intellectual honor, but I'm plenty crude enough to state bluntly that fine-tuning is evidence that "God did it".

    The fact that God does many other things (including things which we can explain scientifically) is irrelevant. The important thing from a Bayesian perspective is that fine tuned laws seem less likely on the assumption of Atheism, then on the assumption of Theism. That is all that is needed for a valid probability argument to the existence of God.

    Of course, it is always logically possible that we will one day discover a natural scientific explanation for this particular set of facts. That is why the Fine Tuning Argument is a probabilistic argument, rather than a strictly deductive argument. To the extent that such natural explanations are currently looking unlikely, it still raises the probability of Theism, because it seems reasonable to think that God would be interested in making sure that life is possible.

    Also irrelevant is discussion of the supposed methodological limitations of "Science", considered as a delimited field of human inquiry. That is just a convention; what we choose to call "Science". If a valid probability argument doesn't meet your criteria to be scientific, then so much the worse for "Science". Call it a philosophical argument based on scientific premises, or something like that, but that doesn't change whether or not the argument is valid. All that matters is whether your observations seem more likely if Theism is true, compared to if Atheism is true.

  36. TY says:


    "The fact that God does many other things (including things which we can explain scientifically) is irrelevant. The important thing from a Bayesian perspective is that fine tuned laws seem less likely on the assumption of Atheism, then on the assumption of Theism. That is all that is needed for a valid probability argument to the existence of God."

    That is the simplest, most economical, and and utterly devastating statement against atheism.


  37. Scott Church says:

    Aron, regarding your last I don't think we disagree at all... at least not on the main points. You'll note that I used an "=" sign in my comment... that was no accident. I wasn't disputing what in the most general sense might be called a god-of-the-gaps argument. I was aiming at something I've repeatedly encountered in the atheist literature and the arguments of my non-believing friends--what more properly could be called a god-of-the-gaps equation. So the argument goes,

    a) Belief in God is a matter of faith alone, where by "faith" we mean belief without proof, or better yet, in spite of it.

    b) Science is based on evidence alone.

    c) As such, science is mutually exclusive to faith, including belief in God.

    d) Therefore, "science cannot explain it" is synonymous with "God did it" ... and vice versa. Do not pass Go, do not collect $200.

    This is what I was challenging, and it's easy to see why this sort of reasoning is bread and butter with atheists... it's a target-rich environment. Creationists find an evolutionary gap in the fossil record, and without missing a beat declare"God did it..." and all atheists have to do is point to previous advances in science, and triumphantly declare God didn't do it the second it turns up. These days when people refer to god-of-the-gaps "arguments," 99 times out of 100 it's this deductive argument they're referring to... or more commonly, using. Now it is true that the existence of nature itself is a very different question than the specifics of how it evolved, but it's unrealistic to think that atheists are going to just lay down their beloved weapon of choice that easily. We're going to keep seeing it...

    Perhaps I could've been clearer, but my intent was to counter it with essentially your probabilistic argument. And I do agree that what we call "science" is largely convention, and to the extent that foundational observations like those of fine tuning prove recalcitrant, it's entirely reasonable to a metaphysical/theological explanation. Indeed, atheism's weakest link is its insistence on Scientism--making an all-encompassing metaphysic of science even as it denies the validity of metaphysical answers. My main point there was that scientific and metaphysical explanations are complementary and can exist side-by-side (to that extent Lewis' Gulliver/Swift "author" analogy is spot-on), but unless the fullness of the living God can be captured by differential equations, observational parameters, and boundary constraints, there's always going to be a limit to how much of His creative work will fall under its purvey.

    But all that said, I do agree with you on the larger point. All that matters is whether our observations seem more likely if Theism is true than they would if Atheism is! :-)

  38. Mactoul says:

    Scott church,
    "science cannot explain it" is synonymous with "God did it" ... and vice versa."

    That's why the idea "God did it" needs to be clarified. What does it precisely mean?. Indeed, in this very case of fine tuning, what I understand is "God did it" is posited only because "science can not explain it".
    Also, it certainly seems that most or all atheists would plump for multiverse over "God did it". Multiverse is scientifically respectable although metaphysically very dubious.

  39. TY says:

    "science cannot explain it" is synonymous with "God did it" ... and vice versa."

    Is the regular non sequitur employed by atheists to mock theism: IF science cannot explain THEN God did it. CURRENT science lacks the explanation and verification but we cannot rule out FUTURE science and evidence, which in any case do not disprove God. Do we need examples? Darwin's theory of evolution does not falsify a creator God, and the major theories and discoveries of the forces of nature have not falsified a creator God, but, in fact, have reinforced the notion of the fundamental being and mind we call God. Physicist Luke Barnes (featured in this post) said facetiously of the God-of-the-gap, non sequitur: “we don't know how lightning exists, so it must be Zeus”. (Let's not co-mingle this issue with "proof" that God exists, which is comprehensively covered in this Blog.)

    The Multiverse hypothesis is indeed a rival theory to the God hypothesis, but on Bayesian probability, the God hypothesis trumps Multiverse. But good you raised that point.


  40. adv says:

    TY, absolutely correct, I have come across very recently , a lot of this is the best theory we have and sure that future science will remove God. But then don't they have to wait for that future Science to prove it before denying the God currently. I have only recently started reading about Multiverse being a good opposition to God, but to me it just takes it to the next level. What is avoiding laws of one from leaking into another. Dark energy, I don't think we have a clue of what it means :). Who created the Multiverse, I am seriously dubious about the universe popping out of nothing. I think this is discussed in another blog. So I posted a question to freethinkers, OK there is no God, now what is next? After a silence and don't seem to get an answer other than trust Science will answer all my question, and basically telling me that I am an automated entity and product of randomness.

  41. ttt says:

    "That is the simplest, most economical, and and utterly devastating statement against atheism."

    ehh, its not that devastating. you have to assume some Bayesian prior probability. what are your assumptions there ?
    i bet i can find something to disagree with.

  42. TY says:

    I agree the prior (probability) distribution is a relevant concern.

    Prof. Wall notes in his presentation: “The bad news is that nobody knows how to calculate probabilities when there is (or even might be) a multiverse!” I take him at his word because I am not a physicist.

    But I will ignore his dire warning just for the sake of argument: even if the prior probability that God exists is exactly equal to the prior probability of some alternative atheistic hypothesis (say the multiverse) so that the ratio is 1, just the relationship P(fine tuning|God) >> P(fine tuning|multiverse) would make the God hypothesis come out ahead of the atheistic hypothesis in a simple application of Bayes Theorem.

  43. Mactoul says:

    I am surprised how the conclusion "God did it" is being used as an evidence for theism.
    If anything, the conclusion that "God did it" presumes theism. After all, one could only conclude that "God did it" IF one believes that God exists in the first place.

    As for the God-of the Gaps fallacy, it is true that it can be and has been used improperly but instances can be given of the correct usage.
    1) Newton, If I remember correctly, invoked God to stabilize planetary orbits since his classical mechanics was apparently giving unstable orbits.
    2) Some theist physicists have proposed that God as the observer who then collapses the wave function as and when needed-the so-called neo-Berkleyean interpretation.

    It can be seen that in both cases God is invoked to get out of the difficulties imposed by the mathematical formalism of the physical theory.
    To the phenomena directly perceived, it can be valid to invoke God. Such as Jesus walking on water or turning water into wine. But it is always fallacious to invoke God in physics, more particularly in mathematical theories.

  44. ttt says:

    "even if the prior probability that God exists is exactly equal to the prior probability of some alternative atheistic hypothesis (say the multiverse) so that the ratio is 1, just the relationship P(fine tuning|God) >> P(fine tuning|multiverse) would make the God hypothesis come out ahead of the atheistic hypothesis in a simple application of Bayes Theorem."

    that makes no sense without details. just switch the words and you have the opposite result

  45. ttt says:

    i guess your Bayesian prior includes the resurrection of jesus ?
    because mine doesn't

  46. TY says:

    1) If you are not a physicist, I suggest first you do some research to find out how many possible universe configurations are likely, and also find out how many of that incredibly large (estimated) number would have exactly the same configuration as ours, and then we can sensibly discuss the likelihood ratio in a Bayesian context and why a "word switch" will not reverse the theistic conclusion. If you are a physicist and you disagree with the numbers already calculated, then you have an obligation to provide the reasons for disagreement, the numerical alternatives you propose, and the underlying theory. The readers who are physicists in this blog would be interested, as I too would.

    2) On the Resurrection, I also suggest you visit the relevant posts of this blog for the resurrection debate. It was quite hot a few weeks back.

  47. Scott Church says:


    If you want a clearer analysis of the probabilistic issues underlying the multiverse you can start with Stoeger, Ellis, & Kirchner (2008). For more on its philosophical implications, and why they do not offer any better account of our universe than theistic worldviews, see Ellis (2008) or Grygiel (2013).

  48. ttt says:

    "I suggest first you do some research to find out how many possible universe configurations are likely, "

    there is no way to do this. we have one example of a universe.

  49. ttt says:

    "why they do not offer any better account of our universe than theistic worldviews"

    i am not saying they are better, but they are simpler than believing God burns bushes and resurects people

  50. Scott Church says:


    While it is true that we have only one example of a universe, and no evidence of others, the first paper I cited above speaks directly to how possible universes can be characterized within current theoretical frameworks, and translated into probabilistic terms. While it doesn't get specific as to the what and how of that (how could it given the current status quo), it does address what can be said today, as do the sources cited therein.

  51. TY says:

    Scott and ttt;

    Scott: Thanks for providing the references and feedback. I add this as well:
    The Road to Reality: A Complete Guide to the Laws of the Universe Reprint Edition
    by Roger Penrose.

    ttt: "there is no way to do this. we have one example of a universe." Scott's reply suffices. But please allow me to emphasise the distinction between "Likely" (which is a probability notion) and "possible (which is observation/ measurement notion.) and Scott was careful to italicise "can".

  52. Aron Wall says:

    The Fine Tuning Argument belongs to a class of arguments known as Design Arguments. Your qestion "Who created the Multiverse, I am seriously dubious about the universe popping out of nothing" belong to another class, namely Cosmological Arguments. My own take on that class of ideas is here.

    First of all, I actually agree with you that the Fine Tuning Argument doesn't provide "overwhelming" evidence in favor of God. I would intead say that, given a reasonable choice of priors, it provides substantial evidence. I'll give an example at the end of this comment.

    Also, to clarify St. Scott's important remarks a bit, it is crucial to distinguish between actual other universes (as postulated by speculative multiverse models) and hypothetical "what if" scenarios (which physicists think about all the time in order to do physics at all). In order to talk about Fine Tuning at all, we need to be able to answer hypothetical questions like e.g. "What if the constants of Nature were different in a particular way, would stars still exist?" This is a purely mathematical question which can be answered by doing a calculation. It does not require observing any actual other universes where the laws of physics are different. (If we couldn't do mathematical calculations like this, there would be no way to determine what the actual laws of physics predict, in order to compare them to experiment.)

    A number of people seem to have been thrown off by my autobiographical comment that I happen to already believe in God on the basis of other arguments. (Obviously, the Resurrection of Jesus is not an a priori truth, but something which requires evidence to establish. But, when updating Bayesian probability based on some specific new piece of evidence, you should include in your priors the effect of any other evidence you've already learned from other sources.) The Fine Tuning Argument does not require you to already be a Christian or any other type of religious believer in order for it to increase your probability of Theism. It is an argument in the domain of Natural Theology (what can be learned about God from general observations of Nature) not an argument in the domain of Revealed Theology (what can be learned about God from specific religious traditions that claim to have received revelation from God).

    simpler than believing God burns bushes and resurects people

    but nobody has ever claimed these things are conclusions of the Fine Tuning Argument! At best, it establishes only the existence of a God who created the universe and who cares about life. To establish that God has done some specific miracle would of course require additional evidence, e.g. historical documentation related to that particular miracle.

    As a specific example, suppose that (before taking into account evidence from Fine Tuning) a particular atheist named "Billy" thinks there is a 5% prior chance that there is a Multiverse of the specific sort that might explain Fine Tuning, and a 1% chance that a God who cares about life exists. (Suppose for simplicity that Billy is not worried about the difficulties defining probabilities in the event that there is a multiverse, and also that he considers any other explanation besides those two much less plausible.) Then after taking into account the existence of Fine Tuning, he can eliminate the other 94% piece of probability space, leaving a 1/6 (16%) chance of God and a 5/6 chance (84%) of the Multiverse. (Again for simplicity, I am treating these as exclusive possibilities.) Thus, Billy has multiplied his probability of Theism by 16 times what it was before! True, he still leans towards Atheism, but if he later encounters an argument that e.g. God has done some particular miracle, he ought to be 16 times more receptive to those claims then he otherwise would be (if he had never learned about Fine Tuning). Make sense?

    (Personally, I don't agree with Billy's low prior probability for Theism, but I wanted to give this example to show how even somebody with different opinions than my own should still have their beliefs affected by the Fine Tuning Argument.)

  53. ttt says:

    "Likely" (which is a probability notion) and "possible (which is observation/ measurement notion.)

    but again you have nothing to base any numbers about these probabilities

    [Added blockquotes to clarify that ttt is quoting TY. At the risk of sounding like a high school English teacher, please mark your quotes!--AW]

  54. ttt says:

    "What if the constants of Nature were different in a particular way, would stars still exist?" This is a purely mathematical question which can be answered by doing a calculation.

    this is a question which can not be answered at this time for many reasons, for example we dont know if the constants are truely independent

  55. TY says:

    “but again you have nothing to base any numbers about these probabilities.”

    Prof Wall notes that the number of universes looking like ours is infinite (not a number). So this is a show stopper from the get go as far as calculating probabilities go. But let’s keep the show going because you ask for numbers. Roger Penrose calculates that the odds of our universe’s conditions arising by pure chance is 1:10 raised to the power 10^123 (Roger Penrose, The Emperor’s New Mind: Concerning Computers, Minds, and the Laws of Physics, Offord University Press, 1989).

    If it is NOT true that the fine tuning of the universe was due to pure chance, neither by pure physical necessity, then most likely due to God. This (deductive) conclusion and the Roger Penrose calculation mean that the likelihood of fine tuning under the God hypothesis should be much, much greater than the likelihood of fine tuning under the multiverse (but no God). This is the main argument than any specific number.

    In any case, by how much? Based on Roger Penrose's estimate, it is by a factor of 10 raised to the power 10^123 (or some other incredibly large number).

    I shamelessly quote these figures because I am not a physicist. .

  56. Mactoul says:

    Aron had a post saying that if there were a theory of everything having just one parameter whose value turned out to be 2*pi/7, then it would be a strong indication of existence of a deeper theory that explained this peculiar value.

    Now, fine-tuning shows peculiar relations existing between the fundamental constants and by the same reasoning, the existence of a deeper physical theory is indicated.

  57. Mactoul says:

    "If it is NOT true that the fine tuning of the universe was due to pure chance, neither by pure physical necessity, then most likely due to God."

    Chance is merely another word for ignorance of true causes. Nothing can be due to chance in itself as chance has no causal force,

  58. TY says:

    Chance as used in the Design Argument (DA) made in my comment is interchangeable with the word randomness (which is the naturalistic explanation). DA says: First, let’s list the explanations for fine tuning and then deduce which on is (logically) valid. The three explanations are (1) randomness, (2) physical necessity, and (3) design. Well, you know how the story ends.

    I think you are concerned the three do not fully exhaust the universe of explanations, and you are right to think this way. Robin Collins deals with this in a Design Argument called “The Restricted Version of the Likelihood Principle.” This mouthful just means his version of fine tuning is not as rigid as the one popularised by William Craig (the one above). Collins permits other explanation or information but, in any case, the straight conclusion is that a Life Preserving Universe supports the God over naturalism. No surprise.

    Sorry I can’t wrap my head around the “causal force” part of your comment, and, in any case, it is not critical to this this DA reasoning. But I could be wrong!

    (P.S: By the way, in all this discussion, you would observe that with our limited human intelligence, there will always be a residual of ignorance (or error term) and we try to understand it and minimize it, but we may never eliminate it, and so we appeal to probability and reasonableness. Hope this doesn't trigger an off-topic discussion.)


  59. Aron Wall says:

    Since Science is based on Approximations, we have to specify what level of modelling we are talking about.

    Considered as an effective field theory, describing physics at measurable distance scales, then it is a mathematical fact that the Standard Model + Gravity has independently adjustable parameters, and we can do mathematical calculations that show when there are stars, carbon etc. The fact that we can do this is uncontroversial among astrophysicists, although there might be quibbling about the exact details.

    However, at very short distance scales we would need a theory of quantum gravity to understand what happens. It is quite plausible that not every choice of low energy parameters can be consistently "UV-completed" into a quantum gravity theory that obeys fundamental principles of physics. Thus it is indeed possible that the parameters of Nature are not all independent.

    Yet this by itself does not form an adequate answer to the Fine Tuning Argument, for the reasons I described on slide 44 (i.e. proposed explanation #4) of my talk. Supposing we hypothesize there is a deeper theory of physics which (to take the extreme case) predicts all of the constants of Nature, there is no particular reason why such a deeper theory would give rise to fine-tuned constants of Nature. (In the absence of some specific mechanism, as covered on the following slide.) Since we don't yet have such a theory, when you construct a Bayesian prior you would still have to spread the prior probability of observing various constants over the various possible values in your effective field theory. But then the odds of getting fine-tuned laws of physics would still be very tiny, falsifying the idea that all of the constants can be determined. So this hypothesis doesn't actually improve the situation.

    (Of course all Bayesian priors are somewhat arbitrary and require making some judgement calls. This is true about all Bayesian arguments, not something special to the Fine Tuning Argument.)

    As a more general remark, since the Fine Tuning Argument is a probabilistic argument, not a deductive argument, in order to refute it, it is not enough to simply point out a scenario in which the premises of the argument do not hold. Instead you have to (1) determine how plausible those various alternative scenarios are, and (2) determine how likely it is on those alternative scenarios that we would still see the things we observe. That's a lot harder than merely raising objections.

  60. Mactoul says:

    "The three explanations are (1) randomness, (2) physical necessity, and (3) design. "

    To my mind, randomness aka chance is no explanation at all but a confession of ignorance.
    Thus I don't know what to make of calculations like Penrose's.
    The (2) physical necessity, does it mean an entirely self-contained theory of everything? The theory in which values of these fine-tuning parameters pops out and which has no free parameter?

  61. TY says:

    This reply is more like a comment than an answer to your point that chance/ randomness is a “confession of ignorance.” I think there is some validity there, if by that you mean “It just happened. Period.” The chance in the Design Arguments is used as the direct opposite of “design”, meaning lack of intention, accidental, etc. To Stephen Hawking and physicist who see no need for a designer (God), this “chance” is not ignorance but the laws of physics at work, albeit in some random fashion. This is my understanding from reading the related literature.

    Roger Penrose says one can actually work out the odds of how our universe is special or finely tuned in regard to the initial state of the universe. He did work out the odds. The physics community has not, as I can tell, come out with any serious critique of this odds ratio, or perhaps similar calculations by other physicists.

    Can you please comment on the “Penrose type” odds for the reason that it is numerically problematic in your view: Infinity divided by another infinity is not a real number.


  62. ttt says:

    Science is based on more than approximations. (observations , experiemnts , etc)

  63. ttt says:

    "then it is a mathematical fact that the Standard Model + Gravity has independently adjustable parameters,"

    that is not a mathematical fact. that is an assumption.

  64. Scott Church says:


    With all due respect, your last two statements are both incorrect.

    First, observations and experiments (etc.) are approximations. Anyone who's ever published peer-reviewed research or a thesis in experimental physics (including me) will tell you... there's no such thing as noise-free observation or methodology. This is why datasets are always published with confidence intervals and/or measures of statistical significance. This is how science works.

    Second, the Standard Model and the field equations of general relativity are mathematical--this is why they're called the Standard Model and the field equations. And yes, these mathematical models and their equations do in fact have tunable parameters that are not constrained by their internal theoretical formalism. Hence, the term fine tuning used by physicists. If a deeper relationship is ever discovered that ties these parameters to their observed values, then general relativity and the Standard Model will be replaced by a New Model... and the mathematical equations of that New Model will have parameters of its own that aren't theoretically constrained by it.

    Differential equations, boundary constraints, and tunable physical parameters are the language of modern physics. They're the only language it has ever used. And this language uses mathematical facts to describe our increasingly accurate, but approximate understanding of the physical world in ever deeper and more precise terms... exactly as St. Aron said. If you dispute this, and know how an exact, parameter-free theory can fully account for the universe we observe with unlimited precision, then by all means publish it... and go collect your Nobel Prize, write your memoirs, and retire to the lecture circuit. At the moment, all you're doing is picking the fly shit out of the pepper and avoiding the larger issues fine tuning presents.

  65. TY says:


    An add-on to Scott's

    In simply algebra:

    Imagine one is trying to solve a puzzle and the scientist has this model (1)Y = α + βX + µ. It is still an approximation of (2) Y = a + bX, which is unknown in every detail.

    µ is the noise (the ignorance, the other bits and pieces of the puzzle that the model cannot capture, usually no matter how hard one tries. But without µ, the (α + βX) term will fall short of EXACTLY generating Y. That's the approximation..

    In science one tries to understand the behaviour of µ and one attempts to fill out the gaps in equation (1) to minimise or, ideally, eliminate µ. It could be a variable was omitted, so one adds a new variable, a new term, and so forth, and, lo and behold, one has a new theory. It could also be that the β can be improved to get closer to b. If that new theory fits or explains the data (Y) better and the predictions are correct, then out goes (1).

    A well know example: The Big Bang Theory supplanted Steady State theory. And there are loads of this type of example in the physical sciences and in the social sciences as well.

    Hope this helps.

  66. Aron Wall says:

    ttt writes:

    Science is based on more than approximations. (observations , experiemnts , etc)

    I take it you didn't notice that the post I linked to, Pillar of Science III: Approximate Models, was just one of a six part series about how Science works.

  67. TY says:


    Here is another informative site on Roger Penrose's odds calculation for the finely tuned universe in its early stage.:

    The physics is beyond me, needless to say.

  68. TY says:


    More on Penrose's odds (ratio) and I won't say more (as I'm using up too much of St Aron space for this fascinating post)

    On the video I referred you to, please move the pointer to 6.01 where Robert Lawrence Kuhn asks Roger Penrose about his famous calculation" "How does that work?". Penrose explains and refers to the underlying methodology based on (1) Bekenstein-Hawking entropy, (2) Boltzmann's entropy formula (that converts entropy into a probability), and (3) Don Page who suggested to Roger Penrose the number 123 for the odds ratio. Roger Penrose has since raised the number to 124 to include dark matter.

    So, we see that great minds went to this calculation that is based on an accepted body of theory.

    By the way Roger Penrose does not hold to any religion beliefs. He's a humanist, but judging from his deep admiration of fine tuning, I am willing to bet he doesn't want to come out and say publicly that God was the fine tuner with the "pin", but offers his "cyclic cosmology" thesis (which he admits in other videos is all speculative stuff anyway).

  69. Mactoul says:

    In Anthony Esolen's Reflections on the Christian Life, I find:
    "When a Richard Dawkins, a rather silly atheist zoologist, conceives of God, he imagines some big creature tinkering with the laws of the universe at the onset of the big bang, turning knobs and pressing buttons so as to fine-tune everything to result in the world we know,.... Then he says it is absurd to suppose such a creature exists. Well it is absurd, because that imaginary creature is not God. First, God is not just big. He is infinite and omnipotent. It is easier for God to create a universe billions of lightyears in its vastness than it is for me to add three and seven-infinitely easier, for "easy" and "difficult" do not apply to God. That is one of the things the sacred writer meant when he was inspired to write "And God said, 'let there be light' and there was light." Just like that; He spoke and it came into being. "

    So does it mean that God does not need to fine-tune? The laws of physics are human invention to understand phenomena. They do not exist in the Divine Mind as some eternal laws whose parameters are needed to be set by God.

  70. Aron Wall says:

    I'm sure Dawkin's conception of God is just as absurd as St. Anthony says, but if an actual theist used a phrase like

    "turning knobs and pressing buttons",

    it would be a mere metaphor or anthropomorphism, since God does not literally adjust the universe like a mechanic adjusting a machine. Like the Bible talking about God delivering people "with his mighty hand, and an outstretched arm", it doesn't mean God literally has a body. But, if it turns out the laws of physics do have free parameters, and that it is logically consistent for the universe to have had different parameters, don't theists have to refer that choice to God's will? Who, if not him?

    The laws of physics are human invention to understand phenomena. They do not exist in the Divine Mind as some eternal laws whose parameters are needed to be set by God.

    I'm not so sure I agree. Surely if God is omniscient then he will at least have noticed that the physical structures happen to conform to certain mathematical patterns, and it is not absurd to think this might be part of what makes creation "very good", as it says in Genesis. But, of course the fine-tuning argument does not require us to see the universe in the same way as God.

    If, say, the fine-structure constant as conceived by us were different, it is clear that there would be certain quite objective features of the universe that would also be different, and whatever those differences are, God could will them. If it is God's will that life exists, then necessarily God also wills whatever is necessary for life to exist. This may involve many other things besides fine tuning the constants, of course.

  71. H.Trickler says:

    Assuming that someday in future a "theory of everything" explains all physical phenomena, imho this would not prove that God does not exist.

    On the other hand, if someday it could be scientifically proved that no such theory is possible, imho this would not be a proof for the existence of God.

  72. Anon says:

    Hello Dr wall, I hope you are doing well. I hope you don’t mind me going off topic but I have been reading your work on the fine tuning arguement and I wanted to ask you some questions about some objections from another theistic physicist named Hans Halvorson if you have time that is. His objections are this

    1. The first one is that he says “nobody in physics has a rigorous probability measurement for parameter spaces so there is no warrant to claim what the chances for the changes of the parameters” then he claims “even if measurement could be figured out nobody in physics are making these predictions “. 2. His second issue is that for statistical mechanics you can determine a measurement for phase space which is called the liouville measure. But then he argues that the lioville measure turns out not to be a good measure for chance and even if it was it turns out that a nice universe would be likely according to the measurement. 3.his last objection is this according to Lagrangian formulation in general relativity we can calculate the probability of the life permitting universes and we find according to that life permitting universes are more likely then life prohibiting ones. Thank you so much for your time. I can’t wait to hear your responses. I hope you have a good day

    [I rescued this from the spam filter and then moved it to a more appropriate post--AW]

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