Yesterday I commented on a fantastic article by astrophysicist Paul Sutter at Universe Today on “The Improbable Origins of Life on Earth.” Sutter now has a follow-up article there, “The Seeming Impossibility of Life,” which provides additional insights into the complexity of life — though I don’t agree with his attempts to dodge the design inference for fine-tuning of the universe. We’ll get to that in a moment. He starts by rightly marveling at the “complexity of the human brain” which he calls “remarkable”:

We are, to put it bluntly, remarkable. There is nothing in this cosmos that even begins to approach anything resembling the complexity of the human brain. There is no other world that we have discovered, within our solar system or without, that can support the dizzying array of chemical reactions that we call life, let alone consciousness.

No doubt life on Earth has impressive characteristics. But is life on this planet unique? Sutter thinks it probably is:

Sure, with enough planets around enough stars within enough galaxies, life is probably bound to happen one way or another, but it appears that life only happened here, once, billions of years ago, when it didn’t appear — or was snuffed out — even in our own solar backyard.

It’s no accident that Earth is home to the only known life in the universe. That’s because our planet appears to be special. Sutter recognizes this as well:

Even our planet is special. Take a look at the other planets of the solar system. If doesn’t matter if you’re using a backyard telescope or the latest NASA robotic gear, the answer is always the same. While every planet looks and acts (and probably smells) different from all the rest, they all share one thing in common: they’re dead.

Lifeless. Uninhabitable. Inhospitable. Barren balls of cold rock. Barren balls of molten rock. Barren balls of exceedingly hot rock buried under thick layers of atmosphere. Barren.

Doubting Fine-Tuning

So Earth is especially suited for life. But what about our universe? Sutter recounts the argument that the fine-tuning of the universe shows “divine intervention” — but then he goes on to disagree with it. Here’s how he frames the pro-fine-tuning position: 

Some argue that the way the universe is constructed is a little too particular. That if any one small thing were to change, from the speed of light to the amount of atomic matter assembled during the big bang, life as we know it would be outright impossible. Perhaps some other form of intelligence could rise up in that strange cosmos, shuddering at the impossible thought of creatures anchored to a planet and swimming in its water oceans. Perhaps not. Either way, it appears that our universe is especially tuned for the appearance of life as we know it, indicating either divine intervention or some conspiracy of physics too far beyond our comprehension to grasp.

But this is where I would have my first major disagreement with Sutter. Here’s how he responds to the design argument: 

To that line of thinking I have this response. We have but one universe for us to study; it is all we’ve had and all that ever will be. As peculiar as this universe of ours appears, we cannot access or interrogate other possibilities. We do not know how special or generic this cosmos is, the same way you could not measure the probability of the Queen of Diamonds appearing in your hand if you did not know the contents of the full deck. That stark reality does not rule out divinity or exotic physics, but it also does not demand them. If you wish to believe in either of those, I will not begrudge you.

This Seems Like a Dodge

Ironically, the rebuttal to Sutter’s skepticism is found in a comment he himself makes: “We have but one universe for us to study”. That’s right — and that’s why Sutter is wrong to dismiss the possibility that we can know our universe is fine-tuned: Science is based upon studying what we know. We know our universe exists, and we know that its laws are fine-tuned to allow life to exist. We know these facts to be true, and thus we can take them into account when asking whether our universe exhibits design. 

Sutter wants to avoid this conclusion through an analogy to a deck of cards. He argues that determining the probability of selecting a particular card requires knowing something about the deck of cards from which it came. That’s fair, but he then claims that if we can’t know anything about the “deck of cards” from which our universe came, then we can’t know whether it’s probable or improbable. For example, maybe that “deck” only includes universes fine-tuned for life (but then we’d have to ask why?), or maybe that “deck” is so large that it is likely that at least one “card” (i.e., one universe) would have the right parameters needed for life — just by chance. The latter argument is essentially the multiverse hypothesis. 

Sure, perhaps we don’t know that there isn’t a multiverse where untold numbers of other universes out there lack the right physics for life. But we shouldn’t assume that this is a realistic possibility that prevents us from making inferences to design based upon what we do know exists. If we can’t infer design from the fine-tuning of the universe, there may be other dangerous implications for science. 

A Hypothetical Cancer Cluster

In the past I’ve argued that “multiverse thinking” destroys scientific logic. My argument involves a hypothetical “cancer cluster” in a town with a chemical plant.

Imagine that 100 percent of an entire town of 10,000 people got cancer within one year — a cancer cluster. It turns out the chemical plant in the town produces carcinogenic chemicals, so the townspeople sue the chemical plant. 

During the trial, the townspeople hire scientists as expert witnesses who testify that the odds of this occurring just by chance are 1 in 10^10,000. Under normal scientific reasoning, they argue, such low odds establish that chance cannot be the explanation, and that there must be some physical agent causing cancer in the town. In this case, the best explanation is that chemicals from the chemical plant caused the cancer. 

The chemical plant has a lot of money, and they hire a wily defense attorney who invokes the multiverse defense, saying: 

Yes, 1 in 10^10,000 is a very low probability. But there could be 10^10,000 universes out there in the multiverse, and our universe just happens to be the unlucky one where this unlikely cancer cluster arose — purely by chance! You can’t say there aren’t 10^10,000 universes out there, right? That means you can’t conclude that my client’s chemical plant had anything to do with this — the whole thing could have happened as a chance occurrence!

Should the jury trust the scientists and conclude the cancer cluster is highly improbable and caused by chemical plant, or should they trust the lawyer and invent 10^10,000 universes where this kind of cancer cluster becomes probable enough to happen by chance? 

The shady attorney deflects criticism saying: “You can’t say there aren’t 10^10,000 universes out there, right?” Right — but that’s the point. There’s no way to test the multiverse, and science should not seriously consider untestable theories. Multiverse thinking makes it impossible to rule out chance, which essentially eliminates the basis for drawing many scientific conclusions. What we have before us is a cancer cluster and a chemical plant, and that’s enough to make a sound scientific conclusion. 

What We Have Before Us

In the same way, Sutter doesn’t argue that there is necessarily a multiverse. Rather, he argues that if we can’t know that there isn’t a multiverse then we can’t draw a conclusion of design. This isn’t all that different from the shady attorney who says, “You can’t say there aren’t 10^10,000 universes out there, right?” But as the hypothetical cancer cluster shows, we could extend multiverse logic and appeals to unknown causes to destroy virtually any scientific conclusion. But that’s not how science works. What we have before us is a universe that is, to all appearances, finely tuned for life. That’s data, and that’s enough to draw a sound scientific conclusion: design. 

Once we allow the unknown or the unknowable to prevent us from making inferences to design that are justified based upon what we know, we’ve let philosophy — or personal preference — influence our science. 

Again, science doesn’t deal in speculations about what might exist. Science deals in what we know. And based upon what we know, our universe appears “a little too peculiar,” as Sutter puts it. We don’t know that there’s a multiverse because we can’t observe it. But we do observe that our universe exists, and we do observe that our universe has special properties that allow life to exist. We can conclude those properties point to design.