I – II – III – IV – V – VI – VII – VIII – IX – X – XI – XII – XIII – XIV – XV – XVI – XVII – XVIII – XIX – XX – XXI – XXII – XXIII – XXIV – XXV – XXVI – XXVII – XXVIII – XXIX – XXX – XXXI – XXXII – XXXIII – XXXIV – XXXV – XXXVI – XXXVII – XXXVIII – XXXIX – XL – XLI – XLII – XLIII – XLIV – XLV – XLVI
Dawkins’ insight here isn’t just useful for explaining everyday occurrences; we can even step back and apply it to the biggest apparent miracle of all – the fact of our own existence. One of the most common arguments for the existence of God is the sheer improbability that something as complex as intelligent life could have emerged without the guidance of some divine hand. We’ve already seen, of course, how complex life isn’t actually that improbable at all once you have large organic molecules that are capable of reproducing themselves – evolution takes care of the rest. But even so, what are the odds that such molecules could come into existence in the first place? One in a billion? You might think that something that only had a one-in-a-billion chance of happening naturally could only be the product of a miracle. But on the contrary, the kind of universe you’d expect to see, if something had a one-in-a-billion chance of happening naturally, was a universe in which there were a billion instances of the thing not happening for every one instance in which it did happen. And sure enough, that’s exactly what we see in our own universe when it comes to complex life. There are billions of planets in the known universe (roughly a billion trillion planets, in fact) – none of which are known to contain any trace of life – and one planet, Earth, that does contain it. The fact that life exists, then, despite seeming so improbable in a vacuum, is no more a miracle than the fact that people win the lottery every day. True, it may be overwhelmingly unlikely that any one particular person will win the lottery, just like it’s overwhelmingly unlikely that any one particular planet will contain complex life, but the fact that someone will win the lottery is practically guaranteed if enough people buy tickets – and the fact that complex life will emerge somewhere in the universe is practically guaranteed if there are enough opportunities for it to emerge (which, considering that there are estimated to be roughly a billion trillion planets in the universe, there certainly are).
If anything, the rarity of complex life in our universe ought to be a point against the religious worldview. After all, if God created the universe for humans to inhabit, then why would he devote 99.999999% of it to nothing but cold, empty space and occasionally some random clumps of lifeless gas or rock? Why waste so much space? As Robert L. Park writes:
If the universe was designed for life, it must be said that it is a shockingly inefficient design. There are vast reaches of the universe in which life as we know it is clearly impossible: gravitational forces would be crushing, or radiation levels are too high for complex molecules to exist, or temperatures would make the formation of stable chemical bonds impossible […] Fine-tuned for life? It would make more sense to ask why God designed a universe so inhospitable to life.
Having said this, of course, there’s a sense in which it really does seem noteworthy that the laws of physics are so finely-tuned as to allow for the formation of things like rocks and molecules in the first place, such that any life is possible at all. If the fundamental constants of the universe (e.g. the speed of light, the charge of an electron, etc.) were even a few percentage points different from what they are, things like stellar fusion and differentiation of the elements could never occur, and life as we know it would be impossible. And although there may be a lot of planets in this universe, there’s only the one universe – so the “large sample size” argument wouldn’t seem to apply here; it really does seem like something more must be going on, right?
But this is a case where the framing of the issue is crucial – because the apparent fine-tuning of the universe only seems remarkable if you’re working backward from the assumption that intelligent life must be the conclusion. It’s like if you were thinking about how our modern society came to exist, and were struck by how many remarkable coincidences had to occur for us to get to this point. If George Washington hadn’t crossed the Delaware on the exact date that he did, would the United States have become an independent nation? If Thomas Edison’s parents hadn’t met at the exact moment that they did, would the widespread adoption of electricity have happened in the same way? Considering how many things had to go exactly the way they did for us to end up where we are now, surely it couldn’t have all just been the result of sheer happenstance, right? But of course, that’s exactly what it was. Our modern society wasn’t a foregone conclusion; there are a billion ways history could have gone, and it just happened to go the way that it did. Similarly, the universe itself could have gone a billion different ways, and although it’s wonderful for us that it turned out the way it did (such that the emergence of intelligent life turned out to be physically possible), that outcome wasn’t preordained – it’s just how things happened to go. The universe could have just as easily had a different set of physical constants and ended up being a thinly-dispersed soup of quarks or something – and if you were looking at that universe from the perspective of someone who thought that a soup of quarks was the most remarkable state a universe could be in, and you were trying to figure out how its physical constants could have been so precise as to allow for that exact outcome, you might find it just as miraculous and inexplicable as we currently find the laws of our own universe. But there’s no objective reason why you should work from the assumption that a soup of quarks is somehow a necessary state for the universe to reach; and likewise, there’s no objective reason why you should work from the assumption that a universe containing intelligent life is the necessary conclusion. We might subjectively consider a universe containing intelligent beings to be more interesting than any other possible hypothetical universe; but that valuation is just that – a subjective one. The laws of physics themselves are totally indifferent as to whether the universe is inhabited by intelligent beings or by a soup of quarks.
Kaye makes a good analogy to explain this point (continuing with his pop-quiz format from before):
Although you are new at golf, you have just hit a beautiful 200-yard drive and your ball has landed on a blade of grass near the cup at Hole 3. The green contains ten million blades of grass. The odds of your ball landing on that blade of grass are 9,999,999 to one against, too improbable to have happened by mere chance. What’s the explanation?
- The wind guided it
- Your muscles guided it
- There is no need for an explanation
- You consciously designed your shot to land on that particular blade
The truth is, no matter how the universe had turned out, it would have been bafflingly improbable for that exact outcome to have occurred. It might seem miraculous to us, now that we’re here, that the universe turned out in such a way that its physical laws were compatible with life – but then again, what other kind of universe could we have expected to see? The conditional probability of finding ourselves in a universe compatible with our own existence must always be 100%; if the universe hadn’t had physical laws that were compatible with life, we wouldn’t be around to notice it! (This is known as the anthropic principle: “Conditions that are observed in the universe must [by definition] allow the observer to exist.”)
In addition to all this, it’s also worth noting that the fine-tuning of the universe’s physical constants might not even be as necessary for the emergence of life as it appears to be. We tend to think of life solely in terms of the carbon-based architecture we’re familiar with here on Earth – but if other forms of life are possible, then it’s also possible that our universe’s physical constants could vary within a much wider range and still leave room for life to emerge. In that case, finding ourselves in a universe compatible with life would be less like hitting a golf ball onto on a particular blade of grass and more like hitting it onto a particular half of the green (i.e. not that unexpected at all). It might turn out that just as universes can hypothetically come in all kinds of different varieties, so can lifeforms also come in all kinds of different varieties to match the physical laws of whatever universe they’re in. As Kenneth Silber writes (quoting Victor Stenger):
There is no good reason, says Stenger, to “assume that there’s only one kind of life possible” – we know far too little about life in our own universe, let alone “other” universes, to reach such a conclusion. Stenger denounces as “carbon chauvinism” the assumption that life requires carbon; other chemical elements, such as silicon, can also form molecules of considerable complexity. Indeed, Stenger ventures, it is “molecular chauvinism” to assume that molecules are required at all; in a universe with different properties, atomic nuclei or other structures might assemble in totally unfamiliar ways.
And as the Wikipedia summary of the subject adds:
Stephen Jay Gould, Michael Shermer, and others claim that the [fine-tuning argument seems] to reverse known causes and effects. Gould compared the claim that the universe is fine-tuned for the benefit of our kind of life to saying that sausages were made long and narrow so that they could fit into modern hotdog buns, or saying that ships had been invented to house barnacles. These critics cite the vast physical, fossil, genetic, and other biological evidence consistent with life having been fine-tuned through natural selection to adapt to the physical and geophysical environment in which life exists. Life appears to have adapted to the universe, and not vice versa.
Silber also points out that some of the parameters that appear to show unmistakable signs of fine-tuning might actually turn out not to be so sensitive to changes in their value after all. In other words, the idea that the universe’s physical constants could even have different values in the first place could be largely illusory:
[Gregg] Easterbrook writes: “Researchers have calculated that, if the ratio of matter and energy to the volume of space, a value called ‘omega,’ had not been within about one-quadrillionth of one percent of ideal at the moment of the Big Bang, the incipient universe would have collapsed back on itself or suffered runaway relativity effects. Instead, our firmament is stable and geometrically normal: ‘smooth,’ in the argot of cosmology postdocs.”
Isn’t this, as George Will writes, “theologically suggestive”? Actually, this particular cosmic mystery may have already been solved, without recourse to theology. The answer lies in the theory of cosmic inflation, first developed by MIT physicist Alan Guth and now widely accepted among cosmologists. Inflation theory states that the early universe underwent a brief period of exponential growth before settling into the slower expansion seen since. And the relevant point here is that omega (which is a measure of the “curvature” of space) is not a constant; it changes with time.
Easterbrook writes that omega had to be “within about one-quadrillionth of one percent of ideal at the moment of the Big Bang.” But actually, omega could have started out at just about any number, and it still would have hit the required “ideal.” Why? Because this ideal is a very special number: one. If omega equals one, the universe is perfectly “flat” or “smooth” (whereas numbers higher or lower mean its geometry is warped by matter and energy). Now, think of a balloon; as it inflates, its surface becomes increasingly flat and smooth. And if the universe (or a balloon) is inflating exponentially – which is to say, extremely fast – then its geometry will get extremely flat very quickly, no matter how wrinkled it may have been before.
As Guth explains in his book The Inflationary Universe, “With inflation, it is no longer necessary to postulate that the universe began with a value of omega incredibly close to one. Before inflation, omega could have been 1,000 or 1,000,000, or 0.001 or 0.000001, or even some number further from one. As long as the exponential expansion continues for long enough, the value of omega will be driven to one with exquisite accuracy.” Moreover, in the billions of years since, as stars and galaxies formed, the curvature of space likely has drifted from its “fine-tuned” value. (In case you’re curious, current astronomical evidence indicates omega is somewhere between 0.1 and two.)
It seems, then, that a number of the apparent constraints associated with our universe’s physical constants might not actually be so constraining after all. For all we know, they could all turn out to be like that to some degree or another. But even if we take it as a given that at least some of our universe’s constants really must fall within a specific narrow range in order for us to exist, there’s still one more possibility we have to account for – which is that maybe this universe isn’t actually the only one that exists after all, and that maybe (just as with planets) there are a billion lifeless universes out there for every one like ours that includes life. You might be familiar with the idea of such a “multiverse,” with countless other universes existing alongside ours, just from its portrayals in science fiction – but it’s actually one of the most popular ideas in mainstream physics, and it elegantly resolves all kinds of mathematical issues that are otherwise very hard to explain. Silber continues:
Why do the seeming “constants” of nature – the strengths of forces and the masses of particles – have the values that they have? It may be that they are not constants at all. Much current work in cosmology points to two remarkable, and interrelated, possibilities: What we regard as the universe may in fact be just one part of a far larger “multiverse.” And the laws of physics may have “evolved” in a process similar to natural selection in biology. These ideas remain speculative, but they cast the “fine-tuning” issue in a whole new light – and they do so without invoking intelligent design.
According to theories of the multiverse, the Big Bang was not a unique event. Instead, numerous “big bangs” have occurred – and continue to do so, in regions beyond our observational horizon. Each “bang” leads to a new universe, one bubble in a vast froth of bubbles. (One might object that the “universe” by definition is everything that exists, but its expanded scope if such theories are correct has given rise to the “universe/multiverse” terminology.) Different universes contain different combinations of forces and particles. If the range of combinations that support life is narrow, then the multiverse might be littered with uninhabited bubbles. But in at least one universe, the “constants” are suitable for carbon-based life.
The latter may be just a matter of chance. Given enough universes, sooner or later one is likely to hit upon the “right” combination for life (even assuming only one type of life is possible). But there may be more to it than that. Consider the theory of “cosmological natural selection” proposed by Penn State physicist Lee Smolin and detailed in his 1997 book The Life of the Cosmos. In this theory, our universe emerged from a black hole in a previous universe; moreover, each black hole in our universe (and other universes) generates yet another universe. Universes that produce lots of black holes therefore have more “progeny” than universes that don’t. The laws of physics are reshuffled slightly with each black hole, and increasingly the multiverse is dominated by universes whose laws are “fine-tuned” to produce black holes.
So what? Well, black holes are formed when massive stars collapse. Stars are massive if they contain heavy elements – elements such as carbon. The selection process thus gives rise to universes such as our own, where carbon and other heavy elements are available as the building material for life.
In God: The Evidence, [Patrick] Glynn dismisses all multiple-universe theories, including Smolin’s. These, he argues, are contrivances produced by “secular-minded scientists” to explain away the evidence for design. Glynn writes that “some scientists have speculated that there may exist billions of ‘parallel’ universes – which, mind you, we will never be able to detect – of which ours just happens to be one. If there were billions of invisible universes, then the series of miraculous coincidences that produced life in this one might not seem so unlikely.” Such theories, according to Glynn, are “reminiscent of medieval theologians’ speculations about the number of angels that could dance on the head of a pin.”
But is the multiverse so far-fetched? The Big Bang seems to have occurred under conditions of extremely high density; similar conditions occur throughout our universe – in black holes. Similarly, Stanford cosmologist Andrei Linde argues that the fast inflation of the early cosmos – which requires merely a small region of curved space, or “false vacuum,” to get started – implies a “self-reproducing” universe. The assumption that there are not multiple universes seems unwarranted by current evidence. Says Stenger: “There’s no law of any kind that we know that says this could only have happened once. In fact, you’d have to invent a law of nature to explain why there was only one universe.”
In addition to these multiverse theories, there’s also a theory that the multiple universes don’t exist alongside each other in space, but come one after another in time, sequentially – that whenever a universe dies, its collapse triggers a new Big Bang that gives birth to a new universe, in an ongoing cycle known as the oscillatory universe.
There’s even a theory that the multiple universes don’t just exist in separate locations or times from each other, but that they all “overlap” and exist simultaneously in a state of quantum superposition. This is known as the “many worlds” interpretation of quantum mechanics, and what it basically says is that every possible path that the history of the universe could have taken – every theoretical timeline it could have followed – actually exists, in parallel with all the other timelines, and that any time there’s a new event that could lead to two different outcomes, the universe splits into two separate universes and both outcomes occur separately. In other words, the universe isn’t just one straight line from start to finish – it’s more like a tree with billions of different branches, where the base of the trunk represents the Big Bang, and the branches represent all the different parallel universes diverging from each other. In some of those universes, Washington never crosses the Delaware. In other universes, he does (and everything else is exactly the same as in this universe), but his hat is a slightly different color. In other universes still, he’s never born in the first place. And in still more universes, no form of life ever comes into existence at all. There’s a universe for every single combination of possibilities – and although we never interact with these other parallel universes, so it seems to us (from the inside) like our own universe is the only one that exists, every possible universe has its own branch of the universe-tree, right alongside ours. Again, this might all sound like science fiction – but the idea is taken very seriously within the field of physics, and there’s a good mathematical case to be made that it actually makes more sense than the single-universe alternative. (See, for instance, Carroll’s post here.)
Of course, as much fun as these “multiple universe” models are to think about, it’s worth stressing that they’re all still purely theoretical at this point. It’s safe to say that the question of whether there’s just one universe or many universes is still an open one, to say the least. Still though, if any of these ideas turn out to be true, it would provide yet another point against the fine-tuning argument, for the same reason that having billions of planets would make it unsurprising that at least one of them would be compatible with life. If you play the lottery enough times, eventually you’ll win – not because it’s part of any divine plan, but simply because there are only so many combinations of possibilities that can exist. The apparent fine-tuning of our universe might seem miraculous to us from the inside, but if there are billions of other universes in which that fine-tuning is absent, then our amazement is nothing but the product of survivorship bias, not the result of intentional design.
For what it’s worth, if we could somehow determine that our universe really was the only one in existence, then I actually do think that the fine-tuning argument would be one of the stronger arguments for our universe being intentionally designed, just in Bayesian terms. That is to say, if a hypothetical universe where a designer existed was more likely to have our universe’s physical constants than a hypothetical universe where a designer didn’t exist, then the fact that those physical values are what they are could in fact constitute a point in favor of the designer existing. It wouldn’t constitute proof, mind you; increasing the probability of a certain proposition by a percentage point or two doesn’t mean much if the baseline odds of the proposition are already extremely low. (Having a stranger come up to you and tell you that they can fly, for instance, should technically increase your estimated probability that they can in fact fly (since their claim would be more probable in a universe where they could fly than in one where they couldn’t) – but that doesn’t make it more likely that they can actually fly than that they can’t.) And it wouldn’t suggest that the designer would have to be divine in nature either; we could just as easily be talking about alien engineers or future computer programmers running a simulation or whatever. But still, I can understand why so many people find the fine-tuning argument so compelling. Even if I don’t think it proves the existence of God, I too find the question of why our universe’s physical constants are what they are to be a fascinating one, just in terms of trying to find out what the scientific causes could have actually been. From a human perspective, our existence really does seem like an enormously improbable one. Still, as Kenneth Einar Himma writes, “The mere fact that it is enormously improbable that an event occurred […] by itself, gives us no reason to think that it occurred by design […] as intuitively tempting as it may be.” Just because you flip ten coins and get ten heads in a row doesn’t mean that you did it on purpose.
Besides, even if you believe that the improbability of our existence must necessarily imply the existence of a divine designer, that belief only introduces an even bigger scientific problem than the one it supposedly solves – and the more credibility you give to the improbability argument, the bigger this problem becomes. As Dawkins writes:
The argument from improbability is the big one. In the traditional guise of the argument from design, it is easily today’s most popular argument offered in favour of the existence of God and it is seen, by an amazingly large number of theists, as completely and utterly convincing. It is indeed a very strong and, I suspect, unanswerable argument – but in precisely the opposite direction from the theist’s intention. The argument from improbability, properly deployed, comes close to proving that God does not exist. My name for the statistical demonstration that God almost certainly does not exist is the Ultimate Boeing 747 gambit.
The name comes from Fred Hoyle’s amusing image of the Boeing 747 and the scrapyard. I am not sure whether Hoyle ever wrote it down himself, but it was attributed to him by his close colleague Chandra Wickramasinghe and is presumably authentic. Hoyle said that the probability of life originating on Earth is no greater than the chance that a hurricane, sweeping through a scrapyard, would have the luck to assemble a Boeing 747. Others have borrowed the metaphor to refer to the later evolution of complex living bodies, where it has a spurious plausibility. The odds against assembling a fully functioning horse, beetle or ostrich by randomly shuffling its parts are up there in 747 territory. This, in a nutshell, is the creationist’s favourite argument – an argument that could be made only by somebody who doesn’t understand the first thing about natural selection: somebody who thinks natural selection is a theory of chance whereas – in the relevant sense of chance – it is the opposite.
The creationist misappropriation of the argument from improbability always takes the same general form, and it doesn’t make any difference if the creationist chooses to masquerade in the politically expedient fancy dress of ‘intelligent design’ (ID). Some observed phenomenon – often a living creature or one of its more complex organs, but it could be anything from a molecule up to the universe itself – is correctly extolled as statistically improbable. [But] in fact […] however statistically improbable the entity you seek to explain by invoking a designer, the designer himself has got to be at least as improbable. God is the Ultimate Boeing 747.
The […] question [is] ‘Who made God?’ […] A designer God cannot be used to explain organized complexity because any God capable of designing anything would have to be complex enough to demand the same kind of explanation in his own right. God presents an infinite regress from which he cannot help us to escape. This argument […] demonstrates that God, though not technically disprovable, is very very improbable indeed.