Argument from Fine-Tuning

The fine-tuning of the universe refers to certain cosmological constants, such as gravitation, that could not have been even an iota different from what it is. Otherwise, biological life or even the universe itself, would have failed to exist. Let’s look at some specific examples of this fine-tuning.

  • If the initial explosion of the big bang had been different in strength by as little as one part in 1060 , the universe would have collapsed back on itself or expanded too rapidly for stars to form.
  • If the strong nuclear force had been different by 5 percent, life would not have been possible.

  • If gravity had been different by one in 1040, then the sun, or something like it, could not exist (which means that life would probably not be possible).

  • If the neutrons were not 1.001 times the mass of the proton, all protons would have decayed into neutrons or all neutrons into protons, which means that life would not be possible.

  • If the electromagnetic force were slightly different, life would not be possible (for different reasons).[i]

The Anthropic Teleological Argument (or Fine-Tuning Argument) is probably the most “scientific” of the arguments for God’s existence and is a (comparatively) new argument for God’s existence. One of its most capable modern defenders is Robin Collins, an American professional philosopher. Collins’s argument depends upon what he calls the “prime principle of confirmation.” The principle is a common sense claim that “whenever we are considering two competing hypothesis, an observation counts as evidence in favour of the hypothesis under which the observation has the highest probability (or is the least improbable).”[ii] Assuming this principle, Collins summarizes the argument as follows.

  1. The existence of fine-tuning is not improbable under theism.

  2. The existence of fine-tuning is very improbable under the atheistic singe-universe hypothesis.

  3. Therefore, the fine-tuning data provides strong evidence in favour of the design hypothesis over the atheistic single-universe hypothesis.[iii]

It should be fairly clear why the fine-tuning of the universe is more probable under theism than atheism. On atheism, the existence of the universe and biological life is incredibly improbable, and this outlandish improbability can even be quantified with reference to the specific parameters of the fine-tuned constants. However, if our universe has a Creator, it is not surprising that we would observe these fine-tuned constants. Creation implies making something according to specific purposes, namely the existence of the universe and biological life.

Why is the explanation God?

If it is established that the universe does require a cause, why should that cause be God? Whatever is responsible for the universe, must transcend what the universe is made of, because whatever it is, it exists apart from the universe. Thus, it can’t be constituted by things or be dependent on things that only came into existence with the universe. That is, it must transcend matter, space and time. Thus, it must be immaterial, timeless and spaceless. It must also be a person. William Craig notes “the personhood of the cause of the universe is implied by its timelessness and immateriality. The only entities we know of which can possess such properties are either minds or abstract objects, like numbers. But abstract objects do not stand in causal relations…Numbers, for example, cannot cause anything.”[iv] Also, the universe cannot be accounted for by science, for at least two reasons. First, science always explains things naturalistically. The universe cannot be explained naturalistically since it represents the totality of natural reality. It would need to be explained with reference to itself, which would just be illogical. One needs to appeal to something other than the thing needing to be explained in order to explain it. Secondly, science explains phenomena by identifying regularities or laws that operate on conditions. However, since there is nothing outside of the universe (or multiverse, whichever you prefer), it cannot be explained through regularities and laws. Natural laws “organize” preexisting material. However, those laws cannot account for how the universe came into being, because there is nothing outside the universe for it to organize. The only other type of explanation we are familiar with is personal explanation: explanation with reference to the intentions and actions of persons. Thus, the universe must have a personal explanation.[v] Thus, the universe must have been caused by a timeless, spaceless, immaterial person.


Who Designed the Designer?

So shouldn’t God require a cause as well?  As we saw in the last section, the designer responsible for fine-tuning must be spaceless, timeless, immaterial and personal. The designer cannot be dependent on anything that came into existence with the universe, since it created the universe. Time, space and matter came into existence with the universe, and so the designer cannot be dependent on those things.

Now we can only say that God would need a cause if we knew that God came into being at some point. But we don’t know that, especially because God is supposed to be timeless (or possess a property that is as good as timeless from our perspective) and so it would make no sense to say that he came into being at some point. (He would need to come into being at some point in time, which doesn’t make sense in a timeless reality). Furthermore, God does not have the other properties that normally lead us to believe that something requires a cause, such as physicality. Thus, the argument implies that God has attributes which makes it doubtful that he has a cause. Secondly, as William Craig has noted, this objection distorts the real nature of explanation. If an explanation is proposed, one does not immediately demand an explanation of the explanation. If you always needed to provide an explanation of every explanation you come up with, you would never explain anything at all. You would, in every instance, need to explain your explanation, and then come up with an explanation of that explanation of that explanation… ad infinitum.

Why ‘God’ and not ‘Gods’?

Why shouldn’t we think that many gods came together to design the universe? The simplest conclusion is that there is only one. If we are satisfied that the argument proves some sort of designer, there is no need to multiply entities beyond what is metaphysically required (i.e. Occam’s Razor). The principle of ontological parsimony would counsel us that where the evidence is the same for either of the above propositions, we should opt for the simpler one: the one that postulates the fewest entities. I could similarly postulate that many gods came together and then they had a huge supernatural fight. The universe was spawned out of this celestial clash of powers. This theory explains the conclusions of cosmological and teleological arguments, but it is invalid as a conclusion precisely because we have no evidence for such a complex story (and it therefore contradicts ontological parsimony). It is therefore unreasonable to suggest that natural theologians have to rule out every logically possible scenario of creation.  Similarly, scientists do not need to rule out every logically possible explanation of the evidence but can comfortably settle with the simplest one.

The Multiverse Hypothesis

The Multiverse refers to a cosmological hypothesis that there are either a very large number of universes or an infinite number of universes. The cosmological parameters we’ve spoken about would be different in every universe. If there are so many universes, it is more plausible to suppose that one of them had the parameters necessary for life. Collins responds to this argument in a number of ways. Firstly, he contends that “everything else being equal, we should prefer hypotheses for which we have independent evidence or that are natural extrapolations from what we already know.”[vi] (Again, this is clearly a common sense principle). We have independent evidence for God based on other arguments for God’s existence and religious experience. God is also a natural extrapolation from what we already know, because we already know that minds produce fine-tuned devices. It is therefore a natural extrapolation from what we already know to postulate God (a very intelligent mind) for the fine-tuning of the universe. We don’t have independent evidence for the multiverse hypothesis and it is not an extrapolation from what we already know. (Also, that the multiverse may be implied by some cosmological models on which there is no consensus is not independent evidence). Secondly, Collins points out that the multiverse likely doesn’t help the atheist’s case, since the universe generator likely also requires design. The universe generator would have to operate under (probably very complex) physical laws. “It stands to reason therefore that if these laws were slightly different the generator probably would not be able to produce any universes that could sustain life.”[vii] So, the multiverse might explain why we have the natural laws we do, but it wouldn’t explain why the universe-generator itself has the laws it does. Maybe, to respond to this, atheist cosmologists will postulate a multiverse-generator, so that universe-generating multiverses are generated at random by a multiverse generator (in other words, a Russian dolls scenario of multiverses inside multiverses). I certainly wouldn’t put it past them with all the crazy speculation they’re churning out (take a look at String theory). But of course, this wouldn’t solve the problem either, since a multiverse-generator will probably be even more complex (and therefore more precariously existent) than a universe-generator. Collins also notes that it seems far-fetched to suppose that a physical mechanism would actually be able to create natural laws themselves. Given that we don’t know (and can’t know scientifically) why there are natural laws, this would be pretty impressive. (We couldn’t know this scientifically, because any scientific explanation would only appeal to more natural laws and thus would be a circular explanation. If you explain natural laws by appealing to more natural laws, you’ve not explained them.) Collins also contends that the multiverse couldn’t explain the “improbable initial arrangement of matter in the universe required by the second law of thermodynamics.” He says that, even given the multiverse, “it is overwhelmingly more likely for local patches of order to form in one or two places than for the whole universe to be ordered, just as it is overwhelmingly more likely for a few letters on the scrabble-board randomly to form words than for all the letters throughout the board randomly to form words.”[viii]

There could be a naturalistic explanation

Since this argument appeals to a naturalistic puzzle regarding the universe it is common to hear critics contend that there could be an explanation in terms of a more fundamental natural law. Collins rightly highlights that this is complete speculation and so could not invalidate the argument. Apart from this, Collins tells us, “the problem with postulating such a law is that it simply moves the improbability of the fine tuning up one level, to that of the postulated physical law itself.”[ix] In other words, what is the probability that our universe happens to have the natural law that makes sure the physical constants are fine-tuned to such a perfect degree? “Under this hypothesis, what is improbable is that of all the conceivable fundamental physical laws there could be, the universe just happens to have the one that constrains the parameters of physics in a life-permitting way.”

Other Forms of Life

In his debate with William Lane Craig, the theoretical physicist, science populariser (and atheist advocate) Sean Carroll makes the following comments on the Fine-Tuning Argument. “It is certainly true that if you change the parameters of nature, our local conditions… would change by a lot…I do not grant that therefore life could not exist. I will start granting that until someone tells me the conditions under which life can exist. What is the definition of life, for example? If it’s just information processing, thinking or something like that, there’s a huge panoply of possibilities…”[x]

Collins responds to this line of argument by contending that “most cases of fine-tuning do not make this presupposition. Consider, for example, the case of the fine-tuning of the strong nuclear force. If it were slightly smaller, no atoms could exist other than hydrogen. Contrary to what one might see on Start Trek, an intelligent life-form cannot be composed merely of hydrogen gas: there is simply not enough stable complexity.”[xi] So a thinking being or a thing that is capable of information processing, as Carroll puts it, would not be able to exist. But Carroll also mistakes the fine-tuning argument for being only about biological life; it is also about the universe itself. The first fine-tuned parameter I mentioned was that if the initial explosion of the big bang had been slightly different, the universe would have collapsed in on itself or expanded too rapidly for stars to form. On the first scenario, the universe itself would not have existed, let alone life. Besides, given how little we know of abiogenesis, Carroll’s argument is just speculation. We don’t know how life formed on our own planet let alone in different cosmological scenarios.  What we do understand about biological life is that it requires a very delicate confluence of different environmental factors in order exist. Thus, appealing to the possibility of unknown forms of life, vastly different from the biological life we know about, is completely unsubstantiated speculation, and could not invalidate the argument.  Based on what we do know life could not exist on these different cosmological scenarios. Since the fine-tuning argument is a probabilistic or inductive argument, a mere appeal to the possibility of alternative forms of life that we have no knowledge of will not cut it as a response.

A.C. Grayling’s objection

A. C. Grayling, a well-known British philosopher, uses an intelligently crafted example as an objection to the argument. He points to the fact that his great-great-great-great-great-grandparents had to do things pretty exactly as they did, and their children, and their children, for Grayling to emerge, just as he is, after 200 years. Grayling says that the history of his ancestry seems very “finely tuned” for his existence, but this doesn’t mean that it is the case.[xii] He argues that this retrospective observation is similar to our perception of the unlikelihood of our existence in light of the delicate initial conditions of the universe. It is unwarranted anthropocentrism to think that human life is the goal of the universe.

Why ascribe particular teleological significance to the delicate conditions of the universe, but not ascribe teleological significance to the delicate conditions of Grayling’s eventual birth? Firstly, to dismiss the explanatory significance of retrospective unlikelihood (as Grayling does) would have ridiculous consequences if applied to scientific disciplines such as natural history.  Secondly, they do not represent the same kind of improbability. Something is unlikely only with reference to something else, and, as a result, we can involve ourselves in all sorts of confusions if we do not specify with reference to what a particular event is unlikely. Almost every event that we can point to is improbable if you think of everything that needed to happen, from the beginning of time, for that event to come about. However, for the most part, the explanation of their unlikelihood is sufficient in the chain of events that bring them about. With reference to other pre-existing conditions, those events are expected. Given a certain environment, which includes agents and the temporal succession of events, many different events will come about. Initial conditions will make it likely that a certain type or range of events will come about. The birth of A. C. Grayling is one of those events that we would expect to obtain given the initial conditions that allow it to be brought about. This means that those events are only unlikely if considered in isolation from the environment that brought them about. The universe has to be considered in isolation, because there is nothing else. There is no environment, which ensured the events that brought it about.  People are born everyday, but universes are not. This is so unless we postulate a Multiverse, but, for the time being, the Multiverse isn’t more than a speculative hypothesis. To put it more forcefully, we can respond to Grayling’s objection in the same way that a multiverse objection might run against the Fine-Tuning argument. The mechanism we know as human reproduction has churned out billions of genetically unique individuals. It is rational to assume that, on pure chance, some one of them will eventually be Anthony Grayling (in all his magnificent complexity).[xiii]

To illustrate this further, we can look at a lottery. It is not surprising that Grayling would be born, because a certain amount of people has to be born, given the conditions of human reproductive capabilities. In a lottery, someone is going to win every once in while, even though the probability of any single person winning is extremely improbable. As William Lane Craig notes, the fine-tuning argument is not analogous to such a lottery. Rather, you should put one black ball among billions of white balls, and then draw one randomly. Then it turns out to be the black ball. Grayling is one of the billions of white balls. While each one is extremely improbable, one of those white balls were going to be chosen. In fact, it is less improbable even than that, since human reproduction is responsible for billions of human beings. So, a lottery analogous to Grayling’s birth would be where Grayling is one of the white balls, and a 100 million white balls are chosen randomly each year ( approximately 131.4 million people are born per year). With those odds, it is not at all surprising that Grayling would eventually be born.

Anthropic Principle

This objection is related to Grayling’s above. If the laws of nature were not fine-tuned, we wouldn’t be here to comment on them. So, the fine-tuning of the universe is not really improbable under atheism, because we exist. I think you will intuitively recognize that there is something wrong with this objection. Just because we wouldn’t be here to comment on the laws if they weren’t fine-tuned, it doesn’t follow that therefore the fine-tuned laws are not very improbable under atheism. The truths of fine-tuning of the universe would be the case regardless of whether biological life or human life evolved at all. It seems to me that this objection implies a sort of idealistic metaphysics, so that if no one saw the tree falling in the middle of the rainforest, then the tree didn’t really fall. Clearly that’s not true, and the parameters of the universe would have the character they do whether or not there is anyone around to observe them. Reality isn’t dependent on human minds. The objection also seems to tacitly presuppose atheism (and is therefore circular). In what way? The fine-tuned  laws of nature might seem very improbable on atheism, but here we are commenting on them, so they can’t be so improbable! In other words, the objector presupposes atheism, because it is only on atheism that the laws look improbable. But the theist could simply reply – yes we are here commenting on them, because theism is true and so the fine-tuned laws and our existence are not improbable. And, even if we knew atheism is true, this argument would still be invalid. Clearly, it doesn’t follow that just because we do in fact exist, that the parameters don’t have the improbability identified. We might have to conclude that our lives are a fluke or a very improbable role of the dice ( or that the universe isn’t really fine-tuned). But it is irrational to conclude that merely because we exist it isn’t really improbable. There are a number of analogies to show the irrationality of this objection. For example, Richard Swinburne tells us, “Suppose that a madman kidnaps a victim and shuts him in a room with a card-shuffling machine. The machine shuffles ten packs of cards simultaneously and then draws a card from each pack and exhibits simultaneously the ten cards. The kidnapper tells the victim that he will shortly set the machine to work and it will exhibit its first draw, but that unless the draw consists of an ace of hearts from each pack, the machine will simultaneously set off an explosion which will kill the victim, in consequence of which he will not see which cards the machine drew. The machine is then set to work, and to the amazement and relief of the victim the machine exhibits an ace of hearts drawn from each pack. The victim thinks that this extraordinary fact needs an explanation in terms of the machine having been rigged in some way…There is indeed something extraordinary in need of explanation in ten aces of hearts being drawn. The fact that this peculiar order is a necessary condition of the draw being perceived at all makes what is perceived no less extraordinary and in need of explanation.”[xiv]

“Sample Size of One”

In an Oxford Union Debate about the existence of God, Peter Millican raises this objection against the fine-tuning argument. “We’re judging on a sample size of one. We only have one universe to go on. So how can we judge what’s probable or improbable?”[xv] Millican doesn’t really elaborate (understandably enough given his time limit). However, we don’t need a sample of many universes to judge the probability of our universe based on fine-tuning. We already have the relevant information about different scenarios in order to judge this probability. We already know that a universe in which parameter x were slightly different, this would happen, or that would happen. Thus given what we know would be consequences of changing these parameters even slightly, we can judge the probability of the existence of the universe and life (on chance) based on how perfectly each parameter must have a specific value. To claim that we need to have samples of different universes is effectively to deny the fine-tuning phenomenon itself, because it would mean that cosmologists don’t really know that x would happen if they changed parameter x slightly. In other words, this objection is the same as denying that fine-tuning is real. And if this objection were true, the Multiverse objection would also be invalid, since there can be no way to judge how the Multiverse increases the probability of our universe on atheism, if we need samples of other universes in order to judge this probability.

What Millican may be referring to is that even though we know that the universe must have certain specific values in order to exist, we don’t know what is the probability of those alternative scenarios actually happening. The principle of indifference, again a common sense principle, contends that unless we have evidence that a different probability structure exists, we should assume that a set of mutually exclusive possibilities are all equally probable. Apart from having intuitive support, the principle is a well-known mathematical principle ( and was not invented for the fine-tuning argument).  So, the principle of indifference on it’s own is sufficient as a response to this objection. For example, if you are only given the information that there is either a red or blue marble in the drawer of the cupboard, then you are perfectly justified rationally to assume that there is a 50/50 chance of getting either a red or a blue marble. Now, there might be other facts that we don’t know about. It might be that I was the one who put the marble in the cupboard drawer and that I like red marbles. But that’s just a possibility. To say that we can’t judge the probability because of this or that scenario might be the case is tantamount to an appeal to ignorance. The fact that there might be information which make the probability different is not reason to say that a 50/50 probability is not the most rational option. In addition,  in order for this objection to work, atheists would need all the alternatives to be more improbable than the universe we do have. Only in that scenario will it be most likely that our universe obtains without design. This is an incredible assumption, which would actually require much more justification than the principle of indifference, especially given that we do not have evidence of anything that would produce that probability structure.  Apart from that, this would be an incredibly striking coincidence, such that it would need to be explained itself, possibly through other natural law(s). But then this raises the question we already looked at. If it is explained by a natural law, why is there a law that makes universes that are not life-permitting improbable? What is the probability that our universe happens to have the conditions that make all universes which are not life-permitting improbable?

Also, many of the alternative scenarios are less complex and require fewer “lucky accidents” than our own does ( and are therefore more probable than our own universe). For example, we saw that if the nuclear force were slightly smaller only hydrogen atoms could exist. This is clearly a simpler universe – it would be easier for this to happen. A life-permitting universe is much more complex than the chaotic, failed universes that are the alternatives. Clearly, a state of affairs that contains less complexity ( that is, that requires less of a confluence of different constants), is more probable than one that is more complex.

[i] Robin Collins, “A Scientific Argument for the Existence of God”, in Philosophy of Religion: An Anthology by Michael Rea and Louis P. Pojman, 5th ed. ( Belmont: Thomas Wadsworth, 2008) 75

[ii] Ibid., 76

[iii] Ibid., 77

[iv] William Lane Craig, Reasonable Faith, (Wheaton: Crossway, 2008) 153

[v] Ibid., 152

[vi] Collins, “A Scientific Argument for the Existence of God,” 81

[vii]  Ibid., 81 -82

[viii] Ibid., 82-83

[ix] Ibid., 78-79

[x] “William Lane Craig and Sean Carroll, ‘God and Cosmology’, 2014 Greer Heard Forum” Youtube Video, posted by ReasonableFaithOrg, March 3, 2014,  39:06

[xi] Collins, “A Scientific Argument for the Existence of God”, 79

[xii] A. C. Grayling, The God Argument: The Case Against Religion and For Humanism, (New York: Bloomsbury, 2013)

[xiii] A. Joubert, “A.C. Grayling and the Design Argument – Part 2” Apologetics Canada, March 30, 2015, accessed March 23, 2017, 

[xiv] Richard Swinburne, “The Argument from Design”, in Philosophy of Religion: An Anthology by Michael Rea and Louis P. Pojman, 5th ed. ( Belmont: Thomas Wadsworth, 2008) 66 – 67

[xv]“Professor Peter Millican, God does NOT exist” Youtube video, 16:18 , posted by OxfordUnion, December 21, 2012,