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The science of universal fine-tuning

June 14th, 2014

Graphs of cosmological variables

Graphs of cosmological variables, with life-permitting regions shown in white. From The Fine-Tuning of the Universe for Intelligent Life by Luke Barnes. Don’t worry – you don’t have to understand these graphs to understand this post!

Recently I was a participant in a discussion on the science of fine-tuning, on Howie’s blog, Truth is Elusive. The discussion got into some questions that I thought were worth looking at in more detail.

Let’s start with the science

There are two big questions relating to universal fine-tuning:

  1. The science – what cosmologists have discovered and calculated.
  2. The explanation – why it has turned out like this. And of course, the big question for many people is whether the science points to the actions of God, or not.

Here I want to just focus on the science. Only after we’ve got a handle on the science can we reasonably begin to draw conclusions.

Basic fine-tuning.

Cosmologists use theoretical physics to analyse how our universe developed from the beginning of the big bang, and how it would be different if the laws of physics, some of the constants and the initial conditions were different. Constants include such basic things as the strength of gravity, the mass and charge of particles like electrons and protons, and the rate of expansion of the universe.

It could have been very different!

Cosmologists have found many cases where small changes in one or more of these constants would result in a very different universe. They have expressed this in three different ways:

  1. If many of the constants were changed just a little, intelligent life would be impossible because the basic building blocks and environment wouldn’t be there.
  2. Of all the possible universes allowed by theoretical physics, a very small subset would allow intelligent life to evolve.
  3. Some cosmologists estimate probabilities, assuming the processes were all random. Lee Smolin has estimated the probability of stars forming to be 1 in 10^229. Roger Penrose has estimated that the probability of a low entropy universe such as ours is 1 in 10^10^123.

How well-based is the science?

Astrophysicist Luke Barnes, in the latest scientific paper I can find (2011), outlines the scientific evidence, and lists 25 scientists, mostly working in cosmology or related disciplines, who accept that the universe is fine-tuned for life.1 I have read books by Rees, Susskind, Davies and Penrose which confirm this. My summary of the scientific facts is at Science and the design of the universe.

It seems there are not many cosmologists who disagree about the basic fact of fine tuning, though a few question some aspects of it (e.g. Lee Smolin says that the formation of stars requires a high degree of fine tuning whereas Fred Adams says it does not). Here are the main objections I have found.

Couldn’t a very different form of life evolve in a different universe?

Life evolves within the limits of its environment. If we had a different universe, it is said, a different form of life may have evolved. It is hard to define the requirements for any life. We shouldn’t only consider carbon-based life.

But we are not talking here about how life could have evolved differently if conditions on earth had been different, but something much more fundamental. Many of the possible universes would be unable to produce life because they do not provide a chemistry out of which to build life. For example, Luke Barnes says:

If the strong force were weaker, the periodic table would consist of only hydrogen. We do not need a rigorous definition of life to reasonably conclude that a universe with one chemical reaction (2H → H2) would not be able to create and sustain the complexity necessary for life.

It is likewise unlikely that life could form if there were no stars and planets to provide habitat and energy, or the universe was very short-lived and re-collapsed relatively quickly, or the matter in the universe was spread so thinly that few particles would interact – all likely outcomes if different parameters were changed. Paul Davies concludes:

There is now broad agreement among physicists and cosmologists that the Universe is in several respects ‘fine-tuned’ for life …. the conclusion is not so much that the Universe is fine-tuned for life; rather it is fine-tuned for the building blocks and environments that life requires.

We don’t know enough about the probabilities to make an estimate

There are clear difficulties with estimating probabilities for fine-tuning.

  • If the range of the variable is infinite, then the probability can’t sum to one as it should.
  • We have no idea what the probability distribution is, and have to make an assumption (e.g. the simple assumption that it’s flat).

So, it is argued, any probability calculation is meaningless. Christian mathematician William Dembski makes this argument.

However the following must also be considered:

We don’t need calculated probabilities

Calculating numerical probabilities is only a small part of fine tuning, and I’ve only seen a few cosmologists do it. The statement “Of all the possible universes allowed by theoretical physics, a very small subset would allow intelligent life to evolve” is descriptively probabilistic, but not numerical. It doesn’t depend on any assumption of the probability distribution of an parameter.

Most cosmologists conclude fine-tuning is real without estimating the probability.

Penrose has done it

Roger Penrose, who was Professor of Mathematics at Oxford University and worked with Stephen Hawking on the science of black holes, is one cosmologist who has made such an estimate. If anyone would know about this, you would expect it to be him.

Fine tuning the probabilities

Several plausible probability distributions have been tested and found to make little difference to the result – the universe is still fine tuned. It requires quite a remarkable distribution to make our universe more probable, but as Luke Barnes says:

to significantly change the probability of a life-permitting universe, we would need a prior [probability] that centres close to the observed value, and has a narrow peak. But this simply exchanges one fine-tuning for two — the centre and peak of the distribution.

So there are significant questions about probabilities, and any estimate must make some assumptions, but so far it appears none of these questions change the conclusion much. Whichever way you look at it, the universe appears to be fine tuned.

What if the laws themselves were changed?

Most of the fine-tuning discussion centres on a couple of dozen constants. But what if the laws were different, for example, if like electromagnetic charges attracted instead of repelled, and vice versa for unlike charges? It is said that this opens up a huge number of possible universes, and who could predict whether these could evolve intelligent life?

Cosmologists have looked at some of these questions, and Barnes outlines six alternative laws that don’t allow life. But what of all the other possibilities?

There is no complete answer to this. The huge number of hypothetical universes that have been examined point towards fine-tuning. That is the best evidence available at present. For fine tuning to be disproved, the cases that haven’t been examined would have to be enormously likely to lead to intelligent life in order to change the fine tuning conclusion.

So we can say that present knowledge points to fine tuning, the rest is presently speculation.

Perhaps an explanation will be found

Cosmologist Sean Carroll, in a recent debate with William Lane Craig, suggested that at least one physical constant once thought to be finely tuned can now be seen to have a quite explicable cause. The initial expansion rate of the universe, once thought to be fine-tuned to the 60th decimal place, can be derived from the equations of relativity, he says. Thus, he argues, other cases of apparent fine tuning might also be explained in the future.

I am having trouble assessing this claim (due to my limited understanding of cosmology). Several references show that the density of the universe is fine tuned to 10^60, but I can’t find any that give the same value for the fine tuning of the expansion rate. But as the density and the expansion rate are related, this may be what Carroll means.

Nevertheless, it seems that most cosmologists agree that to explain this apparently finely tuned density requires the hypothesised phenomenon of inflation to be even more finely tuned (perhaps to a degree of 1 in 10^120). And apparently even Carroll recognises this, for he writes: “The homogeneity of the early universe, however, does represent a substantial fine-tuning …. inflation only occurs in a negligibly small fraction of cosmological histories, less than 10^-6.6×10^7.”. 2

In addition, Barnes outlines 6 issues inflation has to resolve to be able to set up a life-permitting universe, and many of these require some form of fine tuning. He concludes by quoting Hollands & Wald: “although inflationary models may alleviate the “fine tuning” in the choice of initial conditions, the models themselves create new “fine tuning” issues with regard to the properties of the scalar field”

I don’t pretend to understand all of this, I am just trying to report what the experts say. But it seems clear that Carroll’s “explanation” doesn’t change the fine tuning conclusions.

Perhaps an underlying ‘theory of everything’ will explain it all

This would be the solution most cosmologists would probably prefer – the constants are this way because the universe couldn’t have been any other way, granted the laws of physics. But cosmologists such as Rees and Susskind reject this possibility. The maths is too diverse and other possibilities can easily be described, while Barnes says that the most plausible theory of everything (string theory) requires a high degree of fine tuning itself.

But most of the universe is hostile to life!

While astrophysicists continue to search for planets which might support carbon-based life, it is clear that the vast majority of our universe is not friendly to life – e.g. inside or close to stars, the cold emptiness of deep space, etc. Doesn’t this show that our universe is only barely suitable for life?

This may be an argument against the possibility that God created this universe (though I think it would be a weak one), but it is irrelevant to the scientific fine tuning claim I am discussing here. The fine tuning claim is simply that ours is one of the few possible universes that allows intelligent life, or observers, to evolve. This claim says nothing about how much of the universe that life could inhabit.

Victor Stenger’s ‘MonkeyGod’

Physicist Victor Stenger has developed a computer program called ‘MonkeyGod’, which repeatedly calculates whether randomly chosen variables produce a life-permitting universe, or not. The results show that the universe isn’t fine-tuned after all. Stenger has written a book based on these results.

However Barnes has shown, in the paper referenced earlier and a slightly abbreviated version published in Publications of the Astronomical Society of Australia, that Stenger has grossly oversimplified and misunderstood the physics. The simulation is based on only 8 life permitting criteria, and, Barnes says, “three are incorrect, two are irrelevant, and one is insufficient. Plenty more are missing.”

Barnes concludes: “MonkeyGod is so deeply flawed that its results are meaningless.” Meanwhile, Stenger has produced his own paper on the subject but I am unable to find anywhere that it has been accepted for publication. Read more about the Stenger vs Barnes debate on this blog.

Conclusions

The scientific case for fine tuning seems as strong as ever. There are of course uncertainties, but the fine tuning conclusion appears to be significantly more probable and well-based than any doubts.

Notes:

1. He names Barrow, Carr, Carter, Davies, Dawkins, Deutsch, Ellis, Greene, Guth, Harrison, Hawking, Linde, Page, Penrose, Polkinghorne, Rees, Sandage, Smolin, Susskind, Tegmark, Tipler, Vilenkin, Weinberg, Wheeler, Wilczek.

2. Carroll concludes: “… analysis shows that inflation doesn’t really change the underlying problem — sure, you can get our universe if you start in the right state, but that state is even more finely-tuned than the conventional Big Bang beginning.”

12 Comments

  1. @unkleE
    The John Templeton Foundation.

    I am aware that you are familiar with the criticism of scientists who receive research grants from the Templeton Foundation. But this doesn’t seem to bother you as you still use the results they produce using Templeton money.

    I am writing this just in case you don’t understand why Templeton money is so corrosive of good science.

    Science normally progresses by first developing a hypothesis that explains known data on a particular subject. The scientist progresses by experiments or observations that support or undermine the hypothesis. If the hypothesis is undermined the scientist alters it to explain the undermining data or discards the hypothesis altogether.

    All Templeton grants are aimed at confirming the “God hypothesis” or at least making room for it. Those who apply for the grants are well aware of this. Their investigations proceed in a manner that will never undermine the God hypothesis. It is never necessary to lie except perhaps by omission or emphasis. The god hypothesis is one which no Templeton grant recipient will ever produce contrary evidence for or if they do there will be counter evidence of a stronger sort.

    It is entirely pernicious that a Foundation should exist whose sole purpose is to generate pseudo science in favour of their favourite hypothesis.

    You should note that no “fine tuner” using Templeton money ever makes it clear at the start that there is no evidence that physical constants can take any values other than the ones they have and even postulating that if they could there is no evidence relating to the range of values that might be possible thus making the statements of probability entirely speculative.

  2. Hi Gordon, thanks for your interest. But I’m struggling to see the relevance and truth of your comments. Perhaps you can elaborate please.

    1. Which of the scientists I referenced had research funded by the Templeton Foundation and are you alleging they are biased?

    2. You say: “The god hypothesis is one which no Templeton grant recipient will ever produce contrary evidence for or if they do there will be counter evidence of a stronger sort.” But I know at least one well known study that appears to contradict this. What would you say to that?

    3. If all studies funded by Templeton are suspect regardless, would you say studies funded by specifically atheist sources are also suspect and would be less believable in your mind?

    Thanks.

  3. @unkleE

    If all studies funded by Templeton are suspect regardless, would you say studies funded by specifically atheist sources are also suspect and would be less believable in your mind?

    Any funding from any source where the objective is to find evidence for a world view for which no solid scientific evidence currently exists is suspect. Scientific research should either be practical with the aim of addressing particular problems, such as finding new drugs, or should be pure in the sense that the only motive is the desire to increase knowledge about reality whatever the implications. Research aimed at finding evidence for pet non-scientific hypotheses is corrupting.

  4. You say: “The god hypothesis is one which no Templeton grant recipient will ever produce contrary evidence for or if they do there will be counter evidence of a stronger sort.” But I know at least one well known study that appears to contradict this. What would you say to that?

    The researcher concerned had too much integrity to suppress his results or decided he didn’t need further Templeton grants or otherwise resolved the internal conflicts that that kind or “research” involves.

  5. Gordon, thanks for the reply but:

    1. You only answered one of my three questions. Would you be able to answer the other two also please?

    2. You have assumed, but not demonstrated, that Templeton Foundation’s “objective is to find evidence for a world view for which no solid scientific evidence currently exists”. I know little about the Foundation. Would you be able to demonstrate this is true please?

    Thanks again.

  6. Which of the scientists I referenced had research funded by the Templeton Foundation and are you alleging they are biased?

    Yes I am alleging they are biased but only in subtle ways involving nothing so crude as falsifying data. Plausible deniability is the watchword. I’ve already provided one example which effectively just involves omitting emphasizing the speculative assumptions upon which the research is based. If I have time I’ll find another example.

    As for listing who Templeton is giving grants to You’ll have to look that up for yourself.

    Perhaps the example you were thinking of when you wanted to identify an individual who had received funding from Templeton even though his contribution was not in support of the God hypothesis was someone who rubbished creationism. This was a PR exercise on the part of the Templeton Foundation in an attempt to distance themselves from those formidable pseudo scientists at the Discovery Institute.

  7. @unkleE

    You have assumed, but not demonstrated, that Templeton Foundation’s “objective is to find evidence for a world view for which no solid scientific evidence currently exists”. I know little about the Foundation. Would you be able to demonstrate this is true please?

    If you listen to the video on Templeton’s home page with an open mind you will see that instead of discovering knowledge for its own sake or for the purpose of solving real world problems their efforts are bent on verifying their assumption that there is something other than observable reality behind the universe.

  8. Hi Gordon,

    On a blog post discussing the science of fine tuning, you have written a comment on the Templeton Foundation, with the apparent inference that this is relevant to the post. Yet you haven’t named a single cosmologist I quoted who has received this “suspicious” funding.

    So we have no allegation or evidence that is relevant to this post. Is that the case?

  9. @unkleE

    you have written a comment on the Templeton Foundation, with the apparent inference that this is relevant to the post. Yet you haven’t named a single cosmologist I quoted who has received this “suspicious” funding.

    All below have received money from Templeton or are otherwise associated with them:

    Luke Barnes
    Martin J. Rees
    Prof. Bernard Carr
    John D Barrow
    Frank Tipler
    Brandon Carter
    Paul Davies

  10. Hi Gordon, thanks for posting that information, but it wasn’t exactly what you said. You didn’t say “received money from Templeton or are otherwise associated with them” but you said:

    “All Templeton grants are aimed at confirming the “God hypothesis” or at least making room for it. Those who apply for the grants are well aware of this. Their investigations proceed in a manner that will never undermine the God hypothesis. It is never necessary to lie except perhaps by omission or emphasis. The god hypothesis is one which no Templeton grant recipient will ever produce contrary evidence for or if they do there will be counter evidence of a stronger sort.

    It is entirely pernicious that a Foundation should exist whose sole purpose is to generate pseudo science in favour of their favourite hypothesis.

    You should note that no “fine tuner” using Templeton money ever makes it clear at the start that there is no evidence that physical constants can take any values other than the ones they have and even postulating that if they could there is no evidence relating to the range of values that might be possible thus making the statements of probability entirely speculative.”

    That is a fairly comprehensive accusation in several parts:

    1. That fine-tuners (and others) apply for and receive research grants.
    2. The purpose is to confirm the God hypothesis.
    3. They never produce contrary evidence.
    4. The fine tuners are dishonest about the science of the range of possible values of parameters.

    You have offered no evidence for any of these propositions, and I believe I have evidence that some of them are quite wrong as generalisations, even though they may (perhaps, I don’t know) be correct in some particular case.

    So who in your list has received a grant for a project that addresses the question of God or of the fine-tuning of physical constants?

    I know one of them who has received money, but it wasn’t for the purpose you allege in your original comment. When we have a list of fine tuners who comply with your accusation (i.e. you list name, title of grant and funding) then we may be able to discuss.

    Thanks.

  11. Hi Gordon, you didn’t clarify your insinuation about cosmologists receiving a research grant from the Templeton Foundation (TF), so I went looking for information myself. Here, for the record, is what I found by Googling:

    Luke Barnes – I haven’t found any record of him receiving any money from TF. The only association I could find is he lectured at the 2011 St. Thomas Summer Seminar in Philosophy of Religion and Philosophical Theology which was funded by TF, and received a stipend from the university for this.

    Martin Rees – received the Templeton Prize in 2011. I could find no research grants.

    Paul Davies – received the Templeton Prize in 1995. I could find no research grants.

    The Templeton prize is not given to fund research, but is given as a prize for those who have already done significant research or made a contribution.

    Thus none of the three cosmologists I have quoted and you have mentioned actually received a grant that could have influenced them in the way you initially alleged. So, as far as I have been able to find out, none of them has used Templeton money to produce any results as you allege.

    So even if these cosmologists were poor enough scientists and dishonest people to allow funding to determine their results (an accusation you have offered no evidence for), they didn’t actually receive any money that could have done this.

    Happily their reputations remain intact. I wonder if you would be willing, in the interests of fairness, to retract those allegations and insinuations, or else offer more evidence than you have so far?

  12. In a debate between Dr. William Lane Craig and Quentin Smith on March 22, 1996 Dr. Craig has thus given a theistic notion of God in his opening arguments: “[A] personal Creator, uncaused, beginningless, changeless, immaterial, timeless, spaceless, enormously powerful, and intelligent.”

    Here it has been mentioned that God is spaceless and timeless. Not only in the three major religions originating from the Middle East, but in the eastern religions also God has been repeatedly mentioned as spaceless and timeless. Actually the two most common attributes of God that can be found in various religions throughout the world are his spacelessness and timelessness. Now by very simple reasoning it can be shown that the existence of a spaceless and timeless being in this universe implies the relativity of space and time. We say God is spaceless and timeless, which means for God space and time are non-real, non-existent, whereas for us human beings they are very much real, existent. So if God is really there, then in that case the same space and time will have two different values for different beings: For God they will have null values, whereas for us human beings they will have non-zero values. So if God is really there, then in that case space and time cannot be absolute, because for those two to be absolute they must have to have the same values for everybody. Thus the presence of such a God will have some direct effect on the natural world making space and time relative, and science has also shown that space and time are indeed relative. If this reasoning is correct, then I think that there is no justified ground for discarding mystical experience as a mere hallucination. This is one point.

    The second point is that if God is really there, then in that case there will be a permanent state of timelessness in this universe, because we say God is timeless. God does not exist will then mean there is no such state of timelessness. God does not exist therefore means no need is there for science to show how a state of timelessness can be reached or attained, because there is no such state in this universe that requires an explanation from science. But despite that science has shown how a state of timelessness can be reached, because in special theory of relativity it has been shown that at the speed of light time totally stops. If there is no state of timelessness in the universe, then why was it at all necessary for science to show as to how that state could be reached?

    If the non-believers and atheistic scientists in general think that this timeless state has no physical reality, then we can put the following question to them: “Will there ever be any physical explanation for ‘X’, if ‘X’ is not physically real?”

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