The fine-tuning argument for the existence of God is based on the fact that certain physical constants can only have very specific values for life to exist in the universe. If there was even the slightest change in any of these constants, the universe would have evolved in a completely different way, and biological life would have been impossible in our universe. The argument then goes that this is evidence for the creation of the universe by a creator who chose those constants specifically so that we could eventually exist. They contend that it was highly unlikely that those constants are due to chance, given the large number of possible values that they could have taken.

The only refutation I found of the argument from fine-tuning is that there is nothing unlikely about our universe having the right physical constants for biological life, because this debate wouldn't be happening at all unless there was biological life to start with. This is called the anthropic principle.

But this argument doesn't make sense unless there was a statistical population of universes that our universe was pulled from, i.e some form or another of multiverse.

Is it possible to refute the fine-tuning argument for God's existence without subscribing to the idea that our universe is just one in a vast multiverse?

  • 2
    I do not consider fine-tuning an argument for a creator. Because each argumentation to explain the existence of the universe by a creator requires a subsequent explanation for the existence of the creator: What or who created the creator? An answer often heard "The creator is causa sui", that's not an answer but a further unproved ad-hoc claim. - I consider the concept of a creator a problematic concept. It prompts more questions than providing answers. - Hence I propose to keep the theological question separate from the cosmological question and to focus on the latter :-)
    – Jo Wehler
    Nov 27, 2015 at 11:14
  • To the contrary, belief in multiple worlds, at least "possible" ones whether in mutiverse or in the mind of God, is required to even spell out the fine tuning argument. The idea being that those constants could take multiple combinations of values, and it is "highly unlikely" that they would turn out to favor our existence. Without it there is no "fine tuning" that requires an explanation, because without a sample space there is no probability. But even if there was, why should all outcomes be equally likely, and what does that even mean? As in Pascal's wager "probability" here is a figment.
    – Conifold
    Nov 27, 2015 at 23:55
  • At some point down this path, you may have to be very exacting with terminology. Words like "universe" and "multiverse" are very easy to use up until the point where they start getting us in trouble. For example, is there any particular reason to presume that there was a "statistical population of universes" to draw from any more than there was a statistical population of nuclear bombs on the chalk boards of Oppenheimer's team as they frantically built one that would explode?
    – Cort Ammon
    Nov 28, 2015 at 18:25
  • It is actually impossible to prove multiverse theories so if this is the case you are believing in a theory that science can never prove true.
    – Neil Meyer
    Dec 17, 2015 at 16:02
  • @Conifold one could argue for a combinatorial view for possible worlds. If this is the case, the sample space could be seen as abstract recombination of facts and states of affairs without appealing to multiverse (or God's mind). In this sense fine tuning can be spelled without making a commitment to the reality of the alternatives. Afterall when we say that the "result" of a coin toss could be head instead of tail, we refer to such abstract sample space (without referring to real situations) Jun 27, 2018 at 19:50

9 Answers 9


There are problems with even trying to ask the question. We form our ideas of causes and antecedent conditions from the flow of time in the normal universe. It's not terribly hard to envision cause-free structures (like a random graph), or structures where it is hard to find an analog of causality. So if you get too meta with the question, you first need to justify that the question makes sense even in principle.

But if we back off a bit and say, "That we exist is dependent on the fine-tuning of a zillion parameters, but we won't worry about the general form of physical laws, just various constants we can tweak," then it's not at all clear that fine-tuning tells us anything.

Firstly, if you presuppose that the universe must have created humans, of course there are a baffling number of incredibly rare events that must have happened. But if you don't, then given that we can't simulate from first principles an entire universe with different constants, we don't really know that e.g. it's really surprising that our universe supports life. Certainly you can't tweak the fine-structure constant too much before we couldn't survive, but some equivalently complex and aware creature might have been fairly likely.

Secondly, it's possible that a lot of the fundamental constants aren't actually constants but the result of mathematics that we don't understand. We wouldn't say, "What if the universe hadn't had Pi be 3.14159...", because that constant is not a free choice but rather a consequence of Euclidean geometry (which arises in all sorts of contexts). Likewise, I don't think we can tell that things like the electron rest mass and the speed of light are really free to vary independent of everything else.

Thirdly, even if we are surprised by the universe we find ourselves in, it doesn't assure us that a God exists. It depends on the priors, which is sort of assuming that there can at least conceptually be a multiverse of possible universes, some created by God and some not, and our task is to figure out how many of each sort there are, and then see if we can use signatures within those universes to figure out which kind we're in. So, actually, I don't think the fine-tuning argument in favor of God makes sense at all without postulating at least a conceptual multiverse; and once we do that, we have to ask what our priors are on God-created vs. uncreated universes. If we think God-created universes are sufficiently unlikely (at least with the characteristics we observe in ours), then the surprise we feel regarding how tuned ours seems to be to admit our existence may not be enough to override our doubts that God-created universes are common from among the conceptual set (however you measure that, if you even can).

Finally, note that "God" just means any entity capable of universe-creation. The arguments apply equally well to religious ideas of God and to any sort of we-live-in-a-simluation scenario (where God is either the simuluating computational engine, or the entity/ies who created it).


Here is a video lecture that addresses your question:

The Astonishing Simplicity of Everything

Note, it doesn't give a definitive answer to this central question of cosmology because the answer is currently unknown. However, it does answer your question because it demonstrates that belief in a multiverse is not necessary.

Quote from the abstract:

Fundamental physics has reached a turning point. The most powerful experiments ever devised are revealing the structure of the universe with unprecedented clarity. On the largest scales – the whole visible universe – and the tiniest, we are discovering remarkable simplicity, which our theories do not yet explain. ...


Assuming all constants to be uncorrelated is the null hypothesis. If you adopt it, you might ask questions about the large number of possible combinations. But if a hypothesis entails unacceptable consequences it is unacceptable. So one might argue that there is no real fine tuning but deep ignorance. Not so long ago scientists could say "we don't know the answer now, come later". People who insist for all the answers right now end up with unscientific beliefs.


"Refute" has several meanings, including "contradict or deny". In that sense I can refute anything without any justification. That meaning wouldn't produce anything philosophically useful so we ignore that. There is also the meaning "prove that something is wrong". That's a bit too strong. If I prove that the fine-tuning argument for the existence of god is false, then I don't need to believe anything. So I take "refute" as "giving a good argument that something is wrong; good enough that it needs to be looked at, possibly right or wrong itself until a close examination is done".

The anthropic argument doesn't require multiple possible universes. It's possible that the existence of a universe with just the right set of conditions for intelligent life was a priori very unlikely, still here we are, so we are just very, very lucky. Say you find out as a young child that your parents are very rich. Yet they haven't inherited money, they don't run a successful business, they are not film stars or professional athletes, nor bankrobbers or kidnappers, so maybe they won the lottery. Winning the lottery is very unlikely, yet your parents are very rich without any good reason to be rich other than a lottery win. So maybe you were just very lucky.

Without that argument, there is still no need for a multiverse; consecutive universes would be enough. So every 100 billion years there is a new universe, maybe every quintillion years or even more rare there is a new universe where biologial life like hours is going to exist.

Now another question: How "fixed" are these constants? Is it at all possible that our universe could have had a different speed of light? If not then all the universes and multiverses can't give us different constants. Are these constants "unfixed" enough that god could change them - if he wanted to in the first place? If we say no then we are just lucky.

  • 1
    The lottery analogy is an interesting one which captures the luck feature pretty well I think. Of course, the claim is that we all won the lottery.
    – virmaior
    Nov 29, 2015 at 0:29
  • there is really no difference between a multiverse ("still no need for") and "consecutive universes". each universe has their own time (if such a universe even has a dimension of time) and space (if such a universe even has 3 dimensions of space) separate from the others. Dec 1, 2015 at 18:00

i spoke to this issue recently in another question. i had not (until now) seen this question in the wings.

first of all, "fine-tuned fundamental constants" are dimensionless. the speed of light, c (which is really the speed of every other interaction considered to be "instantaneous", not just E&M), Planck's constant, h, the Gravitational constant, G, and the Coulomb constant, k, (or, alternatively, the Permittivity of Free Space, \epsilon_0), are not fundamental constants of the universe to be fine-tuned. that are really just anthropometric expressions of units that we humans have cooked up. Nature doesn't give a rat's ass what units human beings use to measure or describe things. they can all be set to 1, by choice of units and they are in Planck units.

e.g. all the speed of light needs to be is real, finite, and positive, and, if the dimensionless constants remain the same, c will continue to appear to we mortals as the same 299792458 meters per second. if "God" or some other non-mortal being changed it to (in God's POV) to 100 meters per second, we would not know the difference if all dimensionless fundamental constants remained the same. our meter would scale (in God's POV) and our second would scale in such a way that we would continue to observe light moving at 299792458 of our new meters during the time elapsed of one of our new seconds.

that said, there are a few dimensioneless physical constants, probably the most well known is the fine-structure constant which can be thought of as the square of the elementary charge when measured in Planck units. (i.e. Planck units are able to define a natural measure of electric charge without any reference to electrons or other particles. so then it's reasonable to ask "what is the elementary charge in Planck units and the answer is around 1/(11.7), a dimensionless number.) John Baez has a page that itemizes 25 fundamental constants for the Standard Model and 1 more for the Cosmological constant. none of these constants, so far, can be derived from any of the others nor any existing mathematical source (though numerologists have tried) and must be measured from nature. as more new phenomena is discovered (like dark matter or dark energy) and properties of the new phenomena are measured, new fundamental constants will appear on the list. as theoretical physics research makes progress, some of these constants will disappear from the list as they will be explained or derived from other sources. it is not true that if just any of these constants varied just a weee little bit, that the Universe would turn out so radically different that life, as we know it, would not exist. most of these constants, we have no idea how things would be different if some of those constants were different.

but certainly some constants are critical. if the masses of particles (relative to the Planck mass, to make it dimensionless) were significantly different (and i mean orders-of-magnitude different), it's unlikely that the "triple-alpha process" that cooked up carbon in super novae would have serendipitously had energy levels lined up just so that carbon would be abundant and so that the energy levels lined up a bit less well with oxygen so that not all of the carbon got pushed up into oxygen. that is a legitimate Anthropic coincidence that legitimately asks the question "how could that have happened just by chance", suggesting the possibility of purpose.

(remainder copied from other answer)

doubters or deniers of the remarkability of fine-tuning respond with the Anthropic Principle as a non-divine explanation.

i might point out that the Strong Anthropic Principle (SAP) requires quite a leap of faith itself and they will respond with the Weak Anthropic Principle (WAP) which is essentially a tautology or truism. (the SAP says that if it's possible for life to emerge in the Universe and for emergent life to evolve into sentient and sapient beings, then the Universe is compelled somehow for that to eventually happen. the WAP says essentially that "conditions that are observed in the Universe must allow the observer to exist.")

the WAP has to be true, because it's a tautology. and, because it's a tautology, it doesn't say much. it's like saying 5=5. a kinda "empty truth" (and i know i am semantically misusing that term, but i don't care; i am trying to make a point.) then they will say, "Well, the WAP provides a perfectly natural explanation for Fine-tuning by showing that the human perception of Fine-tuning is simply an example of selection bias.

then i will say, "For selection bias to suffice in removing any notion of the remarkability of Fine-tuning of the Universe, that requires a large collection of universes from which to select a life-friendly universe." then they will say "Yeah! Q.E.D!"

they may even point to different mathematical models of the multiverse, some of which are logically consistent and may even be true. but we will never know. because, for the same reason i will never create a God-measuring-device or a falsifiable physical experiment that will show, one way or 'nother, that God exists (or not), neither will they ever create a similar falsifiable experiment demonstrating the existence of any universes outside of the observable universe.

so it's fine to believe in the Multiverse. it might even be true (and even if true, that would only push the argument of infinite regress back a level; i would argue that God created the Multiverse). but i don't need the existence of the multiverse to have an understanding of the existence of me.

however, what if this forever unmeasureable Multiverse doesn't exist? what if the Universe we live in is the only one? that appeared some 13.8 billion years ago (perhaps as a hell-of-a quantum fluctuation)? well, for the 26 or so fundamental physical constants to come out just right so that sufficient carbon was cooked up but for the same process to not fit so well in cooking up oxygen that all of the carbon would have been converted to oxygen, for there to be the other elemental diversity so that small rocky planets such as Earth could exist for life to emerge and beings like us to evolve and wonder how we got here, for all of this to be set to happen 13.8 billion years ago, causes this conscious, sentient, and sapient being to wonder if all of this creativity must have come about from purpose. as opposed to purposeless and "undirected processes".

they can believe in their unproveable explanation (the "Multiverse of the Gaps") and i can believe in mine.


The fact of the fine tuning of the physical constants for the development of life is not evidence for the existence of a Creator in the sense of "proof", but consistent with that existence, and highly suggestive of it for those inclined to think that the universe has an ultimate explanation and human life has meaning.

A multiverse-averse atheist can reply that we do not know whether there is a space of possible values for the physical constants, or a way whereby the constants acquired their actual values. We just see a particular number, and do not know whether that number was selected from a space of possible numbers, what that hypothetical space of possible numbers was, and how the selection was performed. Maybe there was no number space, selection or Selector, and the fact of this lucky number “is just the way it is.”

So, fine tuning can be:

  • explained by the Creator hypothesis (which, if the Creator is the God of classical theism, is an ultimate explanation of reality),

  • explained by the multiverse hypothesis (which is not an ultimate explanation of reality),

  • regarded as just luck, a fortunate brute fact.

Evidently, the explanation of fine tuning by the Creator hypothesis cannot be "refuted" in the sense of "proven to be false".


There is currently no solution for the fine tuning problem, although there are some suggestions.

One of the suggested solutions is the anthropic principle. Another suggestion is Lee Smolin's idea of universes giving rise to other universes as a result of black hole formation. According to Smolin means that universes that generate more black holes should be more plentiful, see his book "The Life of the Cosmos". Both the anthropic principle and the Smolin theory suffer from the problem that there is no well understood way to count the relevant universes. As such, neither theory makes any predictions about what values we should see, and they neither explain nor predict anything.

I should mention that it is conceivable that the values of fundamental constants are not very relevant for the existence of life. It could be the case that life would arise under a wide range of different kinds of laws. But this is unknown since we lack the relevant explanation of how life would arise under those different laws.

For more discussion of ideas along the lines given above, see "The Beginning of Infinity" by David Deutsch, pp. 96-103 and pp. 177-180.


The fine-tuning argument is a species of the argument from design.

First, there are quite a few fundamental constants; and taking Occam's razor onto account, a single universal constant, of which the other constants were mere aspects thereof would be the best possible 'reduction'; then, the natural response would be to set this universal constant to the value 'one'; and then it is as though there is no constant - for what can be more natural than this value?

If this is possible, then is there such a thing as a fine-tuning argument?

Though we can't do this, we can to some extent; in the system of natural units - the speed of light c, plancks constant h and Newtons gravitational constant G are all set to one; that this is a 'natural' thing to do can be seen by the simplification achieved in an equation from Special Relativity:

E^2 = p^2.c^2 + m^2.c^4

Which becomes:

E^2 = p^2 + m^2

Which demonstrates the reappearance of some antique Greek Mathematics - Pythagorases Theorem.

What this suggests is that there is a natural scale of lengths; and taking into account, conjecturally that nothing is continua as such, but fine-grained, atomic or quantised; then we might conjecturally suggest that the natural scale then is the minimal values of such: ie the minimal charge, of which the others are multiples; or the minimal mass and etc, etc.

But then the fine-tuning question disappears; and the question that replaces it is - why is the universe fine-grained or atomic? A better question - physically and philosophically - possibly.

So, does the argument above refute the fine-tuning argument, contradict it or re-orientate it? I would suggest the latter.

And this done without a cornucopia of multiverses being conjured out of wormhole!

  • Good fine tuning problems are posed in terms of dimensionless quantities, e.g. the fine structure constant.
    – Dave
    Dec 1, 2015 at 14:38
  • @dave: that the fine-structure constant is dimensionless is interesting - but what other ones are there? The SM Lagrangian apparently has twenty or so parameters ... Dec 1, 2015 at 15:00
  • spinor.info/weblog/?p=6355 -- the coupling constants of the forces are dimensionless (and ratios between them are what are important); several of the parameters are angles (think "fractions of a circle"); some of them are masses -- I'm not sure if there is a way to describe the SM such that these masses can be given a dimensionless defintion; even so, as far as we can tell today, the relevant parameters are ratios of the masses more so than their individual values.
    – Dave
    Dec 1, 2015 at 15:18

I think the question negates the fact the moon was created by accidentall circumstances.

Without the moon to sustain life, universal constants would not have much of a rule in life as we know it.

  • 1
    I think you're misunderstanding the fine-tuning argument if you're importing not just the moon's existence but the claim the moon was created accidentally. That's part of the point. If I wake up in the morning and I see no one in the house but the dishes are done and there are pancakes waiting at the kitchen table on a plate with a side of blueberries, then the question is whether it makes sense to assert this happened by chance.
    – virmaior
    Nov 29, 2015 at 0:28
  • To me the fine-tuning argument touches on intelligent design which I personally don't have a problem with, e.g., natural teleology, but the moon if indeed accidental is a blatant beyond natural teleology because it touches on a almost supernatural motive.
    – Kris
    Nov 29, 2015 at 1:37

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