The conjecture of "fine-tuning"...and "cosmopsychism"?

            A persistent claim in what one might call the philosophy of cosmology is the supposed “fine-tuning” of the constants of physics to conditions we consider suitable for sustaining living things. Consider, as a representative example, the introduction to a recent essay by Philip Goff in Aeon:

In the past 40 or so years, a strange fact about our Universe gradually made itself known to scientists: the laws of physics, and the initial conditions of our Universe, are fine-tuned for the possibility of life. It turns out that, for life to be possible, the numbers in basic physics – for example, the strength of gravity, or the mass of the electron – must have values falling in a certain range. And that range is an incredibly narrow slice of all the possible values those numbers can have. It is therefore incredibly unlikely that a universe like ours would have the kind of numbers compatible with the existence of life. But, against all the odds, our Universe does.

            Goff goes on to interpret this “fact” of fine-tuning as support for “…the idea that the Universe is a conscious mind that responds to value.” In his view, the Universe has a clear telos – the production of intelligent life. Given how central “fine-tuning” is to Goff’s claim, one might be forgiven for more closely examining the basis for his probability argument – the likelihood of a given universe having physical constants compatible with intelligent life.

            Probability, in its simplest form, is a calculation of the likelihood of a particular outcome given the range of possible outcomes. If, for simplicity, we assume that all potential combinations of the physical constants are equally likely, then the probability of getting a universe that can support intelligent life is a simple ratio: the number of possible universes that we judge could potentially support such life, divided by the number of possible universes. To get to Goff’s conclusion that this outcome is “incredibly unlikely,” we have to know both how many possible universes there are, and how many of them could support intelligent life. In terms of the constants in the laws of physics (those parameters that must be measured empirically, rather than calculated from theory), we need to know what range of variation is possible for each constant, and how much of that variation is compatible with intelligent life. This is where we get Goff’s basic claim of “fine-tuning” - “that range [of values of physical constants] is an incredibly narrow slice of all the possible values those numbers can have.”

            A crucial assumption in this view is that physical constants could potentially vary at all. Goff argues, for example, that we are fortunate that the parameter 𝛆 - representing the efficiency of the fusion of hydrogen to helium - has the value 0.007, since a universe where 𝛆 was slightly larger or smaller would have either very little or only hydrogen. However, the fact that we can simply substitute other values of 𝛆 in our equations hardly demonstrates that other values are actually possible. Further, nothing in our actual experience suggests that 𝛆 can vary; in fact, it seems to be the same everywhere in the universe (the fact that we can observe stars across vast separations in distance and time being but one example). Taken from another perspective, it would be truly remarkable if a parameter like 𝛆 could have a range of values yet somehow always turn up with the same value whenever we measure it. To claim “fine-tuning” is to claim that some entity could adjust the value of parameters like 𝛆; it takes a remarkably imaginative line of thinking to argue that our base assumption about a parameter should be that it is a variable, when all our experience suggests it is a constant.

            This is not new territory, either. In the late 17^th and early 18^th centuries, ingenious observations of Jupiter’s moon Io by Ole Rømer – and conversions to absolute distances by Christian Huygens – showed that the speed of light in a vacuum was both finite and quite fast – about 220,000 km/s, as compared to the modern value of 299,792 km/s. One could have wondered why the speed of light had that particular value…until around 1864, when James Clerk Maxwell calculated what the speed of light had to be if it were an electromagnetic wave. The only speed compatible with mutual electric and magnetic induction – and with the conservation of energy – was remarkably close to the observed results. Before Maxwell, one could have imagined light having many potential speeds and wondered about their consequences, but after Maxwell those flights of imagination were simply implausible. Physics explained why light had one particular speed – the speed toward which experimental measurements were rapidly converging.

            Even if we were to grant that the constants could vary, it is rather difficult to determine how much variation “fine-tuning” advocates think is possible. A factor of two? An order of magnitude? Any number we can imagine? A statistical estimate of variation relies on measuring a value many times in a sample to determine how much variation is likely. To estimate potential variation the physical constants, we must measure each of those parameters in many different contexts and calculate a value and uncertainty. For the gravitational constant – which is notoriously variable in its measured value – the variation in modern measurements is on the order of 10^-4, or one part in ten thousand. For the mass of the electron, the uncertainty derived from measurement is on the order of 0.1 parts per billion (depending on which units one uses to express the mass). In that light, considering universes where the electron is 2.5 times as massive (as Goff does) is utterly hypothetical. Or, to put it another way, we have no reason to think that the physical constants themselves could vary outside a remarkably tiny range of values, and that range itself is likely a product of the uncertainty of our measurements. The careful reader might fairly object that this is simply a restatement of the remarkable constancy of the measured parameters in physics. That is precisely the point.

            Thus the denominator in Goff’s hypothetical probability calculation – the range of possible combinations of the physical constants – is actually quite tiny; from an empirical point of view, only a minuscule range of the values we can imagine correspond to observations of the actual Universe. If the constants are truly constants, the denominator is simply one – ours is the only possible version of the current laws of physics. But what of the numerator – the portion of possible universes compatible with intelligent life? Here again, proponents of fine-tuning are rather vague on their probability assessments for a rather simple reason: we have almost no grounds to evaluate what kinds of universes could support intelligent life in principle, because we cannot possibly imagine all the ways intelligent life could arise. When we think of life in other universes (or even on other planets), “suitable for intelligent life” is usually shorthand for “suitable for life that uses solar energy to convert carbon dioxide and water to oxygen and carbohydrate, later releasing energy in the oxidation of that carbohydrate; most likely using a particular set of nucleotides to encode information and translate that information into protein macromolecules; organizing independent subunits (cells) into hierarchies which can specialize to the degree that a complex internal model of the outside world is represented inside the resultant organisms.” In other words, we are quite good at enumerating the requirements for the intelligent life we know best (humans), but our particular case does little to delimit the range of possible ways to get intelligent life in principle. To do so, we would have to have “comprehensive imagination,” a complete understanding of all the possible ways intelligent life could arise in a variety of possible universes. Our track record of predicting where relatively familiar life might be found on Earth is rather poor (e.g. hydrothermal vent communities); there is no reason to expect our imagination to be any less myopic when conceiving of ways unfamiliar life could arise or produce intelligence.

            In sum, an estimate of the probability of getting a universe that can produce intelligent life (the estimate Philip Goff characterizes as “incredibly unlikely”) relies both on estimating the actual range of possible universes and the number of those universes compatible with intelligent life. Fanciful speculation aside, we have no empirical reason to think that the constants of the physical universe could be anything else but the ones we know. Further, only an excess of hubris could lead us to think that we are able to comprehensively imagine all the ways intelligent life could arise in a given universe. As a result, we can only conclude that “fine-tuning” is a speculative story, and any assessment of its probability is groundless. If a scholar like Goff wants to postulate a “cosmopsychic” hypothesis of the “Universe [as] a conscious mind that responds to value,” he is more than welcome to do so. Offering that hypothesis as an solution to a problem – the popular metaphor of “fine-tuning” physical constants – only works if we have good reasons to think there is a problem at all. 

What would an Intelligent Design theory look like?

When I first read about the "hypothesis" of Intelligent Design, I figured it would go away soon enough. Clearly, I underestimated the degree to which a vocal segment of society will prioritize their personal beliefs in a Designer over all the evidence that suggests there is no design in nature (and yes, I know people talk about natural "designs" all the time in a casual way, just like we use the term natural "selection," when both are mere metaphors that save a lot of verbiage). Advocates of "ID" are constantly claiming it is science (it helps justify putting it in a public school science classroom), so I'm going to take the intelligent design argument seriously enough to put it in scientific terms. What would a theory of Intelligent Design look like, and what testable predictions would it make?

1. If natural structures are the result of a design process rather than undirected evolution, they should be consistently optimal. An entity intelligent enough to design any of the complex creatures we see around us (and powerful enough to put those designs into use) would be expected to do a good job, and the designs should be really good. As a corollary, we shouldn't see a lot of designs that mere humans like us could easily improve.

2. Good designs should not be limited to one taxonomic group. If it's a good design - one that solves a problem well - it should be widely used.

3. We shouldn't see a lot of history in an intelligently designed world. There's no reason a designer would need to provide continuity between the organisms it designed, especially if the intermediate forms between current organisms (what we call common ancestors in evolution) did not perform as well as the ones we see today. (If you like, you could call this prediction a more general version of #2).

4. An intelligent designer would try to make its different designs compatible. In other words, an designer with any intelligence would never design parasites. Why would such a creative and intelligent entity go to all the trouble to design an fancy multicellular creature, then toss in some single-celled bacteria (or even viruses) that could take that creature down?

Now I'm sure some of the folks on the ID side of things will find fault with these predictions; they may say that I'm limiting the mystery of how a Designer would have worked, or its purpose in creating living things, etc. But I'm trying to do science here, and if ID is to be a scientific hypothesis, it has to have specific testable predictions, just like all the great scientific explanations.

So how well does the evidence from nature match these predictions? Not very well. Starting with prediction #1 (designs should be consistently optimal), there's lots of non-optimal design out there. Using our own bodies as an example, humans have this terrible design in our throat, where we cross swallowed food with inhaled air and occasionally choke to death because of it. We also have chronic back difficulties from standing on two legs with a spine that works just fine for animals on four. Childbirth in humans is much more difficult than other mammals, because moms push our babies' big, brainy heads through a small opening in the pelvis (caesarian sections work in difficult deliveries because removing a baby through the big abdominal opening is far easier than the natural route for birth). And finally, anyone who has studied the hormonal mechanism for regulating blood pressure ends up with a big facepalm; the kidneys respond to an decrease in blood pressure by modifying a hormone made by the liver, which is then modified again in the lungs and kidneys, which then both goes back to the adrenal glands to make another hormone which tells the kidneys to increase salt retention in the urine, while all the while the third version of the liver hormone goes to the brain, which makes another hormone to tell the kidneys to absorb more water from the urine. In simpler terms, the kidneys use the liver, lungs, brain, and adrenal glands as intermediaries in the process of the kidney telling itself to absorb more salt and water from the urine. NOBODY would call that a good design. In each case, I'd say we humble humans could have done much better. And those are just a few examples from one species (us).

So how about prediction #2 (good designs should be used all over the place)? There are a lot of species out there that could really benefit from some traits from other groups. Gliding snakes and squirrels are pretty cool for snakes and squirrels, but they are awful compared to true fliers like birds or bats (feathers would be helpful). We mammals would be much better at long aerobic efforts if we had the flow-through lungs that birds do. Those birds would benefit from better recognition of their chicks than just "it hatched in my nest" (you did know that cuckoos are nest parasites, right)? And there are the marine mammals, which do remarkably well given the fact that they have to routinely return to the ocean's surface to breathe ("I could sure use some gills, Shamu!"). Examples of good "designs" limited to one group of organisms abound here.

Now for prediction #3 (we should not see history). I'll just come out and say it: history pervades the record of life on Earth. Extinction has eliminated most of the intermediate ancestors between the species we see today, but we know they were there from fossils. It seems very strange that a designer would respect the ancestry of its various groups so carefully ("no nursing for you - you're a bird!" or "yes, whale, I know you have fins, but they still have to have all the fingers inside"). It also seems strange that a designer would put out an Archaeopteryx - a stepping-stone species between dinosaurs and birds that could never compete against a modern bird, but could make it without any true birds around yet. Why design a cobbled-together intermediate when you could just do real birds?

I can imagine someone arguing that a designer was learning as it went, and that the various groups of organisms were somehow the "rough drafts" along the way (no doubt arguing that we humans are the polished final draft). But that means that this intelligent designer didn't just publish the best designs, but all the "rough drafts." Does that make any sense?

And finally, prediction #4 (different designs should be compatible). I'll leave predators and prey aside, and just point out that there are roughly four species of parasite on earth for every non-parasite species (and plants may justly feel that most of those animals are also parasites as well - at least the ones that aren't helping them with pollination). While parasites certainly have ecological roles and big effects, it's hard to see those roles as necessary ones. Ultimately, why would any intelligent designer handicap its designs with so many effective parasites?

So there you have it. Some realistic and rational predictions from intelligent design, none of which match the actual world we have. I'm sure that ID advocates will argue that I'm setting up a straw man, and trot out their own prediction that they see "complex specified information" or "irreducible complexity" as predictions of the model. You should realize, however, that ID is not the only theory that predicts "CSI" (evolution would do the same), so it hardly qualifies as a prediction that discriminates ID from other explanations. As for "irreducible complexity," every time the ID folks argue something is "irreducibly complex," patient biologists point out the "reducibility" to simpler forms, at which point the ID movement abandons the case and picks out something else. Camera eyes, bacterial flagellae...it's like a big game of evidentiary whack-a-mole. I'm just going to ask you to judge my predictions on their own merits, and remind you that there's this other theory that would predict that organisms would often be bolted together in funny ways, that ancestry would be central to what features those organisms would have, and that struggling to survive would put organisms at cross-purposes all the time. I bet you've even heard of it...