Ratio Christi talk on Fine Tuning

Some of you may recall that last February I gave a talk on Science and the Resurrection to Ratio Christi, an apologetics club that meets at Rutgers University in New Brunswick.

Well, this Monday (the 26th) I'm giving a talk on "Explanations for Fine Tuning":

Were the laws of physics selected to produce life? This talk will
describe several examples of fundamental physics parameters which seem to be "fine-tuned", i.e. taking on special values that permit life to exist. We can use techniques from modern particle physics, such as the "renormalization group flow", to help decide which claims of fine-tuning are real, and which are only apparent. Some examples, such as the Cosmological Constant Problem, seem very unlikely to have any normal scientific explanation. I will argue that the only plausible solutions involve God or a multiverse.

Any of you who are in the area are welcome to attend.  This one is at 9 pm at the College Ave Student Center, room 411C.  For more details, see their Facebook page.  Please note that the location and time are different from my previous talk.

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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23 Responses to Ratio Christi talk on Fine Tuning

  1. Talk sounds very interesting. Any chance you'll be posting it? Or making available for those of us not close to the ivied walls?

  2. "I will argue that the only plausible solutions involve God or a multiverse."

    Or both?

    (I endorse Robert's comment, if that is possible please.)

  3. Luke Barnes says:

    A third vote for a video from me.

  4. Aron Wall says:

    I don't know yet if there will be a video (just sent an email asking). At the very least I should be able to post my slides.

    Of course, there could exist both God and a multiverse. (This viewpoint has been suggested by my colleague St. Don Page.) There is no reason why they cannot both exist; they are rivals only in the sense that they are both claimed to be explanations for fine tuning. (So if one of them does explain it in a fully satisfactory manner, then you wouldn't need to invoke the other one to explain fine-tuning, although one might still believe in it for some different reason.)

    I have your book on pre-order! Do you know yet when it is going to be released?

  5. Mactoul says:

    God can not be an explanation in physics, by the very nature and competency of the subject.
    While the hypothesis of multiverse is a very dubious physics. If multiverse can not be observed, then it can't be physics.
    So, is fine tuning a problem in physics or in theology?

  6. Scott Church says:

    Wow... I so wish I could be there Aron! If not video, is there any chance of getting a transcript to go with your slides?

  7. Aron Wall says:

    The fine-tuning argument is a philosophical argument that happens to take physics facts as some of its premises. Since we live in an interconnected cosmos, it is not possible to make completely watertight separations between the various branches of knowledge (for example, economics and chemistry have different subject matters, but an economist can take into account that a chemical easily explodes when explaining why it is more expensive to transport.) It doesn't matter whether you call it physics or theology, the only question is whether the arguments is rational.

    I agree that the multiverse hypothesis is quite speculative. But I don't think a thing must be observable to be physics. Sometimes it happens that a model of physics predicts both A and B, and then when A is observed and confirms the theory, it is reasonable to believe that B also exists even though it is not directly observable. For example it is not possible to observe things outside your past lightcone, but they probably still exist.

  8. Mactoul says:

    "it is reasonable to believe that B also exists even though it is not directly observable."
    Acceptable with the qualification that the entity B is a postulated entity in the physical theory and not a entity that exists per se.
    In other words, the entity B exists purely theoretically, a mathematical convenience perhaps.
    The distinction between the corporeal bodies that exist per se and physical bodies that exist in physical theories is a useful one and has been made by the philosopher Oderberg. Thus, a physical body is abstracted from a corresponding corporeal body.

  9. Daniel says:

    Thanks for posting this announcement. As I am discussing this topic with my high school seniors next week, I am looking forward to being there ! Thank you Aron. I agree with others that it would be great if you could post your slides !

  10. Luke Barnes says:

    Hi Aron,
    Official hardback release date is 6th October, in the UK. It's available on Kindle now. I think the shipping date is later in the US.


  11. Aron Wall says:

    I don't think you thought about my specific example (stuff outside our past lightcone).

    A galaxy inside our past lightcone has the exactsame metaphysical status as one outside our past lightcone. The things in them (e.g. stars) are the same kinds of things that exist in our own galaxy! It is just their relationship to us that differs---some things are too far away for light to have reached us yet. Thus they are unobservable, yet presumably still real.

    Thanks! I'm looking forward to reading it.

  12. Scott Church says:

    Just got my copy of Luke's book... can't wait to start it! When are you going to write one Aron...? Can't wait for that either! :-)

  13. Mactoul says:

    If the galaxy outside our past light cone is unobservable (and not merely unobserved) then how do you know it exists? From some physical theory? But then you must believe in the physical theory and the extrapolation thereof?
    This extrapolation may be believable or not, depending upon demand made upon our credulity. A galaxy more or less might be credible, a whole universe isn't.

  14. Mactoul says:

    "A galaxy inside our past lightcone has the exact same metaphysical status as one outside our past lightcone."
    I should say it does not. An observable galaxy is what we are directly perceiving. The other galaxy is merely a supposition. It may be a true supposition but the metaphysical status is clearly different.

  15. Aron Wall says:

    That's epistemology, not metaphysics. I'm a realist, so I believe that things exist even when we aren't looking at them.

    I agree of course that the reliability of the extrapolation depends on the plausibility of the particular physical theory in question. Currently the physics models that predict a multiverse are totally speculative, but one could imagine that changing one day if they are confirmed by specific enough predictions (in our own universe).

  16. Mactoul says:

    "I believe that things exist even when we aren't looking at them."
    Those things are observable things, we merely happen not to observe them.
    My realism does not demand that non-observable things exist in the same sense observable things do.
    And extraordinary claims need extraordinary evidences. It is clearly inelegant and un-parsimonious to invoke whole universes into existence to preserve one's pet theory.
    This problem with modern physics-playing fast and loose with existence-was identified by Fr Jaki and begins with Heisenberg's uncertainty principle. One starts with creation of virtual particles and one ends up with creating whole universes.

  17. Kyle says:

    How did the presentation go? Did you get that video?

  18. Aron Wall says:

    Sorry everyone, they didn't end up recording it. But you can download my slides on this post!

  19. g says:

    Does it make me a bad person that every time I see this post title I expect it to be followed by something like "The Ratio of Christ is very finely tuned. If it were just a little larger or a little smaller, salvation would be impossible."?

  20. Boltzmann says:


    What is your opinion about this paper sir ?

  21. Aron Wall says:

    The argument seems to be that while our universe is good for producing life, an even smaller cosmological constant would be (slightly) better.

    While it is clear that arranging life to exist is the sort of thing that the biblical God might be expected to do, it is far from clear that he would necessarily act to "maximize the fraction of baryons that form living organisms or observers", especially if God has other goals besides the production of life.

    (Many people presume that Theism implies that God only cares about human beings, or perhaps intelligent life as a whole. But the Bible does not in any way teach this, and in fact teaches---see e.g. Job, Ecclesiastes, Psalm 8, Deut 29:29, Isaiah 55:8-9, Romans 11:33-34---that we cannot fully comprehend God's reasons for creating the universe, nor his reasons for giving human beings our own position in that universe.)

  22. Boltzmann says:

    What about this
    I saw a lot of papers telling me that fine - tuning is an illusion, ex
    - Cold Big Bang Cosmology as a counterexample to serveral Anthropic arguments
    - Why the Universe is Just so ?

  23. Aron Wall says:

    I hope you don't think you should believe things just because they are on the arxiv? I'm not an expert in the area of stellar formation, but I did notice that even though the paper is from 1997 it only has 1 citation on INSPIRE. While this does not automatically imply that the paper is bad, it is at least suggestive that the arguments in question have not been accepted by the scientific community.

    In any case, this paper would only addresss one particular anthropic coincidence, not the rest (e.g. it would not in any way explain the fine tuning of the cosmological constant).

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