What are the odds against a Life Permitting Universe

There is a claim that forms an integral part of the Teleological Argument for the existence of God, an argument that claims the universe has clear signs of purpose. This claim is that a life-permitting universe is so unbelievably unlikely that no thinking person should be able to say it happened due to chance. The argument implies the assertion, then, that life was the purpose of the universe.

Trying to explain the argument ends up taking you in circles: the fact that the odds of life are so astronomically small, means it is apparent that life if the goal; then it is only because life is the goal that we can apply significance to the odds against it. And around and around it goes.

But, ignoring the circularity for a moment, what are the actual claims?

The idea is that there are fundamental values in the physical laws that, if they were anything different, would not permit life. For example, if gravity were stronger the early universe would have collapsed back in on itself, or if the strong nuclear force were any weaker, then nucleii would never form and there would be no element to compose life out of.

It seems to depend where you look to see exactly what the numerical odds are against life. William Lane Craig says Roger Penrose calculated this value to be 1 in 10123 (Craig, no date). Penrose’ work isn’t actually cited, just his name, so I can’t find out what assumptions Penrose made or if he even made this calculation. (I also can’t find when Craig published the essay in which he says this; none of his references are post 1989.)

The argument that goes that:

The actual argument

  1. This low probability event actually happening has 3 possible explanations: physical necessity, chance or design;
  2. It isn’t chance or necessity;
  3. Therefore it is design.

It is worth saying that Craig doesn’t refer to this as an “event”, but as “Fine tuning”, and other apologists tend to follow his lead. But, that term is slightly confused and so I have avoided it.

Quick Fire rebuttals

  1. You can go about striking off the options in a different order and reaching a different conclusion: it isn’t design or chance, therefore it is physical necessity; it isn’t physical necessity or design, therefore it is chance. We have good reasons to not accept any of the three options and remain in that dreaded cloud of ‘I don’t know’.
    • We can rule out chance because the odds presented are so very low.
    • We can rule out design because there are no known entities not contingent on the universe capable of such a design.
    • We can rule out physical necessity as there are no known mechanisms that would lead to such a necessity.
  2. In principle, we can avoid the probability question by invoking a multiverse. We don’t have to believe a multiverse is real ― just to point out that the possibility of a multiverse creates an option in the argument that combines physical necessity and chance: it’s a probabilistic outcome, but nature played the numbers game.
  3. In a game of poker, every hand has the same odds against it. It is only when a hand that is already defined as significant comes up that we notice the odds against our hand. A royal flush isn’t less likely than any other hand, it’s just more significant. So, I take you back to the circularity mentioned earlier: the fact that the odds of life are so astronomically small, means it is apparent that life if the goal; then it is only because life is the goal that we can apply significance to the odds against it.
  4. God doesn’t need these fundamental values to be ‘just right’ for life; God can do what God wants, and if God wants to create life in a universe where life appears physically impossible, then God can. The fact that life emerges in a universe where life can emerge appears like evidence for naturalism, not supernaturalism or theism.
  5. These might not be fundamental laws, and the fine tuning problem might go away with a better understanding. This has already happened once. The expansion rate of the universe used to be one of these ‘finely tuned’ parameters, with a probability against it being what it is of 1 in 1060. But, if you derive the expansion rate of the universe from General Relativity instead, it becomes a physical necessity (i.e. probability of 1 in 1).

The rebuttal I mean to focus on today

Sean Carroll describes the kind of work you would have to do to actually decide on the probabilities against the universe fostering intelligent life. Step one is to create some mathematical space that counts all the possible universes. Step two is to create some mathematical space of all universes that could have life arise in it. Step three is to do an integral of two against one to derive a probability. His point is that nothing like this has been done or is being done.

Here are the problems with the steps:

Starting, methodically, with step one, we will take a brief look into what a space for all possible universes might look like. Limited by my own lack of intelligence and a 2D screen to display my work on, I will start by illustrating the issue with one arbitrarily chosen physical parameter. Lets just call it ‘Parameter 1’.

We have a lot of important questions to ask at this stage: what are the upper and lower bounds for Parameter 1; what are the highest possible and lowest numbers? Give a continuum from the (unknown) lowest possible value (“-P?”) to the (unknown) highest possible value (“+P?”), what is the probability distribution: are all outcomes equally likely, or are some outcomes more likely than others? How we could discern the probability, given that we can only sample the one universe we are in, seems like a hugely speculative project.

All possible values for parameter 1

This one parameter, Parameter 1, does not constitute a space that counts all possible universes yet. Wikipedia claims there are 25 such parameters (Wikipedia contributors, 2018) for us to sort out like this. And I say “sort out” rather loosely, as we haven’t actually sorted anything out ― we’ve just raised some questions fundamental to the methodology.

But let’s move on to step two before we start confusing step one with many parameters. (We’ll come back to that.) The first question is where the current value for Parameter 1 lies between -P? And +P?. If the probabilities are equal, then this doesn’t matter, however, if different outcomes have different probabilities, then whether we are sat in a relatively high or low probability value does matter; it describes the probability (along that particular parameter) of the Life that is us (LU). More interestingly we can ask: is there some other completely different value that ― holding all other constants equal ― would help give rise to a other types of life (LO)?

Boundaries for life under Parameter 1

We don’t actually have a good definition of life or a good understanding of how life came about in this universe. We don’t really know if the universe is teeming with life or if life arose of Earth against the odds. Therefore, we really don’t know what the upper and lower bounds for the values of Parameter 1 could be that would still give rise to life as we know it; that is why they are denoted with question marks, again: -LU? and +LU?. And we really don’t know if other types of life would emerge under very different values.

There’s far too many unknowns here to discuss clearly, so let’s simplify the model down to considering life only as we would recognise it and then go back to step one to introduce another of these 25 parameters: Parameter 2. Consider the whole graph space the mathematical model of all possible universes, and only where I have coloured Green to be a ‘Life as we know it’-permitting universe. You can already see that if you throw a dart at the graph from a distance, you’re not likely to hit it; that is quite a small area where life permitting conditions for both Parameter 1 and Parameter 2 line up.

Changing more than 1 parameter at a time

But there is a paler green area and a diagonal dotted line. What is all that about? Well, it’s a visual representation of yet another question: if we change the value of both Parameter 1 and Parameter 2 together, is there some other area on the graph where life as we know it could emerge; the pale green area with a question mark in it? Even more intriguing, is there an entire relationship along the dotted line where turning one value up and the other down preserves life as we know it?

I originally created the graph with other life included in different colours, but it became too difficult to read. That said, don’t take that as a cue to discard the question of other types of life.

The pattern continues: where two parameters create a large 2 dimensional ‘space’ to depict all possible universes, and a smaller ‘space’ in green depicting all ‘life as we know it’-permitting universes, considering 3 parameters creates a 3D conceptual space with a green cube inside it. After that, a 4 dimensional space… etc.

Step three is to do an integral equation on the 25 dimensional space and the 25 dimensional green area within it. If, in step one, you figured out that the probability of each value in each dimension is equal, then you have an easy division question: what percentage of the total space is occupied by green space? However, if the probabilities are not equal, then you have a much more complicated picture in front of you: imagine the space varies in density (‘probability’) across its entire reach; the question now is what percentage of the total mass of the area is overlapping with the green space?


Every step of the method to actually calculate the probability against a life permitting universe is wrought with currently unanswered questions. And this makes the whole project meaningless.

Firstly, are the multiple variables you are considering really the variables you need to consider? As we saw briefly with the expansion rate of the universe, the variable can evaporated quite easily.

Secondly, once you have established with variables, what are the upper and lower bounds for what that variable could take?

Third, what is the probability distribution across each variable?

Then, life: what is it? This question defines the areas across the distribution that are considered significant. I simplified the models I presented by reducing it to life as we would recognise it: LU. But there is the consideration of other life (LO) out there in conceptual space that would ask the same questions if it came to be; that life is equally significant to the question.

Lastly, how does the permissibility of life in a universe change as more than 1 variable is altered at once? If one parameter is reduced life becomes impossible, but could you compensate by turning another parameter up?

All of these questions have to be answered before we can get to some mathematical count of all possible universes and then the count of life permitting universes inside it.



Craig, W.L. (no date) The Teleological Argument and the Anthropic Principle | Reasonable Faith. Available from: https://www.reasonablefaith.org/writings/scholarly-writings/the-existence-of-god/the-teleological-argument-and-the-anthropic-principle/ [Accessed 6 September 2018].

Wikipedia contributors (2018) Fine-tuned Universe. Available from: https://en.wikipedia.org/w/index.php?title=Fine-tuned_Universe&oldid=858295346 [Accessed 6 September 2018].

29 thoughts on “What are the odds against a Life Permitting Universe”

  1. The entire argument is bogus, of course. When the argument was first posited, we knew very little about the universe. For example, we thought all of the visible stars were all that there were. About 100 years ago we discovered that there are more galaxies in the universe than stars in our galaxy. How does this affect the argument’s premise “It is not chance because the odds are so low.” Consider what happens to the odds of winning any horse race if you bet on one race, versus betting upon millions of races. The odds go from unlikely to almost certainty.

    These arguments are not arguments that can prove anything, all they can do is convince. The target of these arguments is, therefore, true believers because they are already convinced. By making a philosophical argument that sounds important that reinforces the opinions of believers, the person crafting the argument gains status in the believer community. But no non-believers are convinced, nor is anything “proved.”

    Do you know of any such arguments for the existence of a creator or a creator god made by someone not a believer?

  2. The argument falls apart completely when we realise that this universe is, in fact, far, far, far better “designed” to produce black holes. It’s estimated that for every life-capable planet there are millions, if not tens of millions, of black holes.

    So, if the purpose was to produce black holes, then great, job well done.

      1. I learned about Lee Smolin from The God Delusion. Because I am actually that much of a cliché.
        I know how much momentum Fecund Universe theories get, but they are a neat solution to unitarity problems (violations of the conservation of information) in black holes…

      2. Well, we don’t know *how* to get the information back out. It’s an engineering problem.

        Read a wild paper, last year I think, showing the math for why we might be inside a collapsed 4-dimensional star, creating the 3D hypersphere we call this universe.

  3. 10^123? I would also like to know how one comes up with this because the amount of assumptions that had to be made here are enormous. We don’t know how life started on a lifeless planet so how can we make any claims to know how rare the conditions are?

    I think the most important thing here is that there is still a very human-centric type thinking going on here. Intelligence is just an evolutionary adaptation and evolution is not convergent. Life could exist on countless planets, but simply not have the ability to create radio telescopes. I can imagine than there are many planets where they are unlikely to get beyond the stage of single celled organisms. It’s also possible that intelligence might have evolved by our extremely xenophobic and really don’t want to be found. It’s also possible that many planets full of life have existed in the past and have already died. The period of time in which we could potentially detect other life has been so small in comparison the age of the universe. It’s amazing how desperate some people are to provide proof of God. A kind of proof that wouldn’t stand up in any other area of knowledge, and yet we are supposed to be convinced. I think the real answer is that it is supposed to impress people without the requisite knowledge to know the difference between proof and bullshit. THen they stand up a debate people like Hitchens or Carroll and the same people are impressed because they honestly can’t tell the different between science and pseudo-science, and all the know is one guy is arguing on behalf of things they already believe, so he must be right.

  4. Hey allallt-

    Does the thought ever cross your mind as to how you KNOW two plus two equals four? No, no, not what you learned in kindergarten, but HOW you know. A serious question regarding standards)

    Hint: No evolution needed. Truth was true long before the heathens wore diapers, and long before Einstein was a glimmer in his pappy’s eye’s.

    2nd hint: superstitious apes who wear hanes boxer shorts may be very good spellers…………but they always seem to flunk basic arithmetic, as their brains know something does not add up. Maybe one day, in the illusionary world of Star Trek where apes fly planes………………

    Oops. Did I say brains? Some things the common ant relies upon to embarrass all non thinking atheists. Yeah, right, like there is a legitimate discussion regarding God’s non existence. Your numbers, math, false science, endless theories, and reliance upon lying pseudo archeologists are but a water drop in the ocean of irrelevance.

    Just a suggestion: Consider the wonders of creation as being perfectly designed and maintained by a God whose brain is a bit larger than yours, and capable of creating math so you have no excuse in not finding His design under a microscope, through a telescope, or anywhere else. Consider WHY man has devolved, and animals still be animals; the common jackal need not apologize for his ravaging acts as he watches thugs in Detroit. They have a reason for feasting on what is natural, while the depraved acts of men are an embarrassment to humanity. (just as the good book says of course)

    And don’t even get me started on abortion, where the mathematics of death are perfected. So, the graphs and numbers are meaningless and a smokescreen.

      1. De-volving as I said John. Garbage dumps. landfills loaded with rubber and plastic; college grads who can’t spell kat, pollution unheard of; store clerks in every country who can’t give change for a dollar without a computer………. So what if men can make a brass trumpet; been doing that for eons.

        You call that progress?

      2. Depends who controls the dictionary now doesn’t it?

        If, by ‘evolution,’ you mean going from something else, then to human, then to something else as in another ‘kind,’ of course not, as this so-called evolution would be a preposterous lie upon common sense and a further breach upon humanity.

        If however, you simply mean that evolution is a twin of ‘adaptation,’ as in acclimating to tech and info, such as going from a rotary to a smart phone, if you call that ‘evolution,’ fine, go for it, but a far cry different than challenging the Creator to His own creatorial prerogatives, and a denial of the ‘kinds.’

        The bald eagle would tend to argue with you, that it was once a swimming or crawling piece of brainless lint, or that a lion was a baby catfish just waiting to mature and leave the life and times of the river……..

        But try reading the book of Genesis john, unaided and unfiltered by the dry and useless opinions of others. It’s all there, as it should be.

      1. Hi allalt-
        It was you who relied upon charts, numbers, and graphs, If you cannot see the overt connection, I can’t help you further.

        You wrongly assume that ‘basic math’ does not reveal absolute truth. You are missing the boat.

        How you consider two plus two reveals your understanding of so much more. Apparently you have no use for that.

        Then there is the greater question: why can’t apes tie their shoes or count to three……..

      1. WordPress didn’t used to have these.
        It had idiots, sure. And it had bots that posted dozens of links.
        But this is just weird. What’s it for?

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