5 objections to the fine-tuning arguement

Of the two-dozen (or so) arguments for God’s existence that Christian philosophers marshall in the cumulative case for God, one stands above all the others in how often atheists admit that it keeps them up at night.

Yes, fine-tuning. So if you’re curious what all the fuss is about, let me take you on a whirlwind tour, exploring what physicists have discovered, unveiling my favourite way to turn fine-tuning into an argument for God, and offering some brief responses to 5 common objections atheists raise.

So what is fine tuning?

Cosmic fine-tuning is the scientific discovery that, at the deepest level, our universe is surprisingly calibrated to allow for life. The initial distribution of mass energy. The strength of gravity. The cosmological constant. The strong nuclear force. In the literature on this subject, penned by scientists of all religious and irreligious stripes, physicists have identified how dozens of these fundamental building blocks of our universe—the initial conditions, laws, and constants—fall into an extremely narrow life-permitting range, as though someone has finely-tuned all the dials so our universe could support life. Run computer simulations where you turn these dials in either direction, changing the numbers often even by a hair’s breath, and you get a completely sterile universe. No galaxies. No stars. No chemistry. No life.

For an extended run-down of these finely-tuned features, check out A Fortune Universe by my physicist friend Luke Barnes. Or check out the entries on Fine-Tuning in the Blackwell Companion or Oxford Handbook of Natural Theology. Or for the pixel addicted, Reasonable Faith’s animated video, linked in the description, does a good job spelling out the scientific summary.

Fine-tuning arguments, then, take this scientific observation of fine-tuning, and seek to make the case that this is somehow good evidence for God. They are a species of design arguments, or in the philosophical vernacular: teleological arguments. From the Greek telos, implying they reveal a purpose or goal.

And these type of arguments have a long history. In the 18th century William Paley famously put forward his Watchmaker analogy, arguing that if you discovered a watch on a beach, this intricate design is beyond nature’s forces to blindly craft, so you rightly infer an intelligent agent designed the watch. Paley then applied the same inference to certain biological features he observed, like the human eye, arguing it must be a product of intelligent design.

Going back further, the 4th century bishop Gregory of Nazianus made a similar observation about how nature speaks of design, offering a less deistic metaphor of a lyre and its orchestrator. He writes, “No one seeing a beautifully elaborated lyre with all its harmonies, orderly arrangement, and hearing the lyre’s music will fail to form a notion of its craftsman-player.” I love that image.

In other words, whether using timekeepers or instruments, Paley and Gregory echo Psalm 19:1 and Romans 1:20 in the claim that nature speaks, pointing to how certain features of creation exhibit such intricate and beautiful design, the best explanation of which is that our universe is a cosmic cathedral, designed to lead us to recognise and worship God as the cosmic craftsmen.

So what exactly is the fine-tuning argument?

Perhaps the most famous version defended today comes from William Lane Craig, and seeks to establish design deductively. The syllogism goes like this:

Premise #1: The fine-tuning of the universe is due to either physical necessity, chance, or design.

Premise #2: It is not due to physical necessity or chance.

Conclusion: Therefore, it is due to design.

In this version premise 2 tends to be the controversial premise. But the current state of physics does not predict or require our finely-tuned numbers; indeed we can imagine them being different and run the simulations. So physical necessity doesn’t seem like a live option. And when you consider the improbability of any one of these dials being so finely-tuned, let alone dozens of them as though in a combination lock, chance is just not a reasonable explanation.

With physicists trying to calculate the numbers, William Lane Craig likens the chance of cosmic fine-tuning to a blind archer randomly launching an arrow into space and hitting the bullseye on a target thousands of kilometres away.

Agnostic physicist Paul Davies likens the fine-tuning of just the strong nuclear force to the chance of a blindfolded person randomly choosing a single special marked coin out of a billion stacks of coins, when each stack covers a North-American sized continent and stretches up to the moon.

And the staunchly sceptical physicist Fred Hoyle says that the fine-tuning of the universe is as likely as a group of monkeys composing Shakespeare’s Hamlet by randomly banging away on typewriters. Hoyle concludes: “A common sense interpretation of these facts suggests that a super-intellect has monkeyed with the physics…” Talk about a stunning confession from an atheist.

So Craig’s version of the argument is certainly defensible. Personally, though, following conversations with physicist friends like Luke Barnes, my favourite versions of the fine-tuning argument are a little more humble in their conclusions, framed abductively rather than deductively, coming up with theism as the inference to the best explanation.

Premise #1: The universe appears fine-tuned for life.

Premise #2: The best explanation of fine-tuning is theism.

Conclusion: Therefore, fine-tuning provides some evidential support for theism.

Here the goal is simply to show that theism is the best explanation of the facts of fine-tuning, moving the evidential needle towards the God’s existence.

So let’s look at 5 common sceptical objections to the fine-tuning argument.

Objection #1: God-of-the-Gaps Reasoning.

Some atheists have responded to the fine-tuning argument by claiming this is naive god-of-the-gaps reasoning, another example of appealing to God to cover over scientific ignorance. Richard Dawkins and Neil deGrasse Tyson, for instance, argue that the apparent design in nature that led to Gregory’s lyre or Paley’s watch, like the intricacy of the human eye, has since been explained away by naturalistic mechanisms, such as those that drive Darwinian evolution. So we don’t need God anymore. We just need more science, and in the end any appearance of design will ultimately disappear, including from fine-tuning.

But this objection runs the risk of affirming a naturalism-of-the-gaps, where in the face of a good argument for design, against all the present odds of available evidence, atheists confidently affirm science will one day vindicate a naturalistic explanation of fine-tuning.

And while it is true that some Christians perhaps have been too hasty to appeal to design, with later discoveries of naturalistic mechanisms calling the God hypothesis into question, the fascinating thing about fine-tuning is that the deeper we have dug scientifically into the origins of our universe, that is where the evidence of design screams loudest.

I love the quote from Werner Heisenberg, the Nobel prize winner and father of quantum mechanics: “The first gulp from the glass of the natural sciences will turn you into an atheist, but at the bottom of the glass God is waiting for you.”

Cosmic fine-tuning is not a surface level observation; it is at the very bottom of the glass of our universe. No appeal to cosmic, chemical, or biological evolution has any bearing on the fine-tuning of these numbers, and so this is no appeal to scientific ignorance. It is because of our deep scientific knowledge of fine-tuning, along with an absence of reasonable naturalistic alternatives, that renders the inference to theism a rational step.

Objection #2: The Hostile Universe Objection.

Another common objection is that the universe is almost entirely inhospitable to life. The vacuum of space. Extreme temperatures. Dead planets. Black holes. Fermi’s paradox shows just how poorly this universe is fine-tuned for life, because we can’t see it anywhere else. So if fine-tuning for life was God’s goal, then this hostile universe is not what you would expect.

But this objection simply dodges the point, comparing the hostile conditions of the universe negatively against the hospitable conditions of earth. Fine-tuning, however, does not predict that the universe should be crammed with living beings from end to end and from start to finish; nor does theism. No the fine-tuning argument simply tries to offer an explanation as to why, despite the odds, life is possible anywhere in our universe.

And as it turns out, upon investigation, nothing in our universe is wasted. Smaller, denser universes tend not to last long; so we need a huge universe. And we need the cold vacuum of space to enable scientific discovery. If there was atmosphere everywhere, breathable air for instance filling our solar system, our sun’s warmth would dissipate to rapidly, and worse, we would’t be able to observe anything beyond. No stars. No galaxies. No scientific answers to the questions of our origins. So not only is our universe fine-tuned for life, it is also fine-tuned for discoverability, as though someone wanted us to be capable of unlocking the secrets of fine-tuning woven into the fabric of creation.

Objection #3: Superfluous Fine-Tuning.

Some critics have questioned why God would even need to finely-tune the universe for life, given He could easily create and sustain life on Earth in sort of a supernatural bubble, miraculously protecting us from the hostile or chaotic parameters beyond.

But apart from how God supervening on nature might undermine His revelatory purposes, which you can explore in my videos on Divine Hiddenness, perhaps the bigger problem with this sceptical suggestion is that it blows up science.

This is precisely why modern science didn’t grow out of ancient worldviews where nature’s forces were in constant flux controlled by the whims of the gods. Because without order in the universe, there are no physical laws to be discovered, and no regularity to be harnessed for human enterprise and technological advancement. That is why the Christian story, of a rational God ordering his creation in Genesis, was fertile soil for the scientific revolution. And since God’s goal in the Christian story is human development as the stewards of creation; for us to grow in spiritual, intellectual, and moral maturity; I think a finely-tuned universe is predicted on Christian theism, nullifying this objection.

But again, don’t miss how critics here dodge the central challenge of fine-tuning, offering no naturalistic alternative to the design hypothesis.

Objection #4: The Multiverse Objection.

This really is the only serious game in town for refuting the fine-tuning argument. Here critics say Christians are too hasty dismissing chance as a reasonable explanation, as fine-tuning is extremely improbable only if you have a single universe. But what if there is an infinite number of universes, each with the fundamental dials randomised? Surely then, with so many rolls at the cosmic dice, eventually you would get a life-permitting universe, right? So couple the existence of the multiverse with the anthropic principle, and of course we observe a finely tuned universe, as only a finely-tuned universe would produce observers like us in the first place. If a multiverse is possible, some would even say plausible given some current physical theories, chance is a viable explanation if cosmic fine-tuning.

Now what I love about the multiverse proposal is that, as a philosophical objection to the fine-tuning argument, it is such a strong tip of the hat to the powerful scientific evidence of design. Basically, you need to appeal to an infinite number of unknown worlds to get around the improbability of this one world we do know being so finely-tuned. But let me spell out a few major problems with this objection.

First, for the nerds among us, check out a brilliant rejoinder to the multiverse objection developed by Roger Penrose in his 2004 book The Road to Reality. Warning, this is a technical thought experiment about what kinds of universes and observers would be more likely if we are the product of the multiverse, but if you want to get the gist of his argument, just Google Boltzmann Brains. You’re welcome.

A simpler problem with the multiverse objection is that it seems to run afoul of Ockham’s Razor, which favours explanations with fewer entities and ad hoc propositions. The argument here would be that the multiverse objection unnecessary posits an infinite number of entities in order to explain our universe, rather than simply appealing to a single Creator.

A more serious nail in the coffin of the multiverse objection is that physicists who are experts in fine-tuning, like Luke Barnes, Roger Penrose, and Paul Davies; have pointed out that all our viable models of a multiverse actually required a multiverse generator that is extraordinarily fine-tuned. The net result would be that even if this objection is successful, it fails, only kicking the fine-tuning problem back a step.

But my major beef with the multiverse objection is that, without any solid evidence, and with no possible access to any in the future either, it explains away the good evidence we do have of design right now, in what amounts to a philosophical sleight of hand.

For an analogy, imagine we were playing a high-stakes game of Poker, where after dealing out 10 hands, I just happened to get a royal flush every time as the dealer. Obviously I clear out all your chips, and you lose your life savings. What would you rationally conclude? Did I just get lucky, or am I cheating?

Now suppose, before you shoot me for dishonest dealing, that I tell you this really did just happen by chance, and that the improbability of this crazy event can simply be overcome by the fact that there are an infinite number of universes in which you and I have played this exact high stakes game an infinite number of times, and you just happen to exist in the unlucky reality where I randomly get 10 royal flushes. Now, that might be a possible explanation. But will you believe it? Hell no. Because there is no evidence to support that conclusion. Nothing. You have no access to any other universes. You can’t see if we’ve played this game an infinite number of times. You can’t rule out if I’m cheating in every single one. All you have is access to this one game. So, given the odds, the best explanation is that someone has fixed the cards. And no doubt you would act accordingly by pulling the trigger or calling the police.

See the analogy to fine-tuning? Where given all the hallmarks of design in the one universe we can observe, and the only universe we can ever observe, the multiverse objections just wreaks of motivated reasoning; a sleight of hand to avoid the implications of the most reasonable conclusion.

Now there other objections worth considering, like if our universe is designed, who designed the designer? So check out our video on, “Who created God?” Or you can explore Nick Bostrom’s observations around selection bias, which I think Richard Swinburne has soundly answered with his firing squad analogy.

But let me close with one final, more personal objection.

Objection #5: The Complex Objection.

More popular level critics, like the atheist YouTuber Alex O’Connor you saw at the beginning, have argued that the fine-tuning argument is simply too complex to serve God’s purposes in revelation. I mean it depends upon a super recent discovery that billions of people never had access too across history, and it requires a working familiarity with physics and probability that rules out the kinds of people who never clicked on this video, or the ones who clicked away. Surely such a technical argument is a weird way for a God who wants us to have a personal relationship with him to reveal Himself to humanity, right? I mean it doesn’t exactly move the heart strings to draw you towards God.

So let me close with two responses I hope will help. First, given the degree to which atheists have clung to science as a tool to dispel belief in God, it seems entirely appropriate to me that in His foreknowledge and providence, as an act of grace and a serious challenge, God would disrupt this sceptical strategy by opting for fine-tuning to be discovered at the bottom of the scientific glass. Atheists demand strong scientific evidence of design? God says, here you go. And like Jesus said to the Apostle Thomas after presenting him with the evidence, now the challenge is given to stop doubting and believe.

And second, on a more personal level, you don’t have to be a science whiz to experience how nature speaks. The fine-tuning argument might not be your cup of tea, but it is just one technical and scientifically grounded species of a more intuitive step; to observe order and beauty in nature, in the stars of the night sky, or a butterfly’s dance, or a spider’s web, and allow the awe it inspires lead you to worship God as the craftsmen of this cosmic cathedral. That’s a step we all can take personally in response to nature’s design.