Over at Why Evolution Is True, Professor Jerry Coyne is currently engaged in a very gentlemanly debate with ex-Anglican priest Eric McDonald on the meaning and existence of free will. Eric McDonald has opened with a very thoughtful article entitled, Free Will: A First, Very Tentative Step. Today, I’d like to focus on the first part of Professor Coyne’s extended reply to Eric McDonald. This post is an especially interesting one, as it not only reveals scientists’ real reasons for accepting determinism, but their reasons for accepting naturalism as well. I shall attempt to show that in both cases, scientists who accept these “isms” are not thinking rationally: they are guilty of making an illict extrapolation which is not warranted by the available evidence. Additionally, I will argue the case for scientific naturalism is built on the romantic myth that for the past 2,500 years, science has been continually enlarging the range of phenomena known to be naturally explicable, leaving fewer and fewer phenomena unexplained. I shall then put forward an alternative metric of progress in science, in place of the one proposed by Professor Coyne. Finally, I will conclude my essay by drawing a contrast between Coyne’s illicit extrapolation to scientific naturalism and another famous extrapolation in the history of science which everyone accepts as legitimate: Newton’s theory of universal gravitation.
Let’s return to Professor Coyne’s debate with Eric McDonald on free will. In his opening article, Eric McDonald highlights a critical flaw in Coyne’s scientific case against free will: scientists haven’t put forward any arguments in defence of determinism. McDonald anticipates a response that Professor Coyne might make, and then explains why he regards this response as unsatisfactory:
You might say that, as a scientist, determinism is a “properly basic” principle (in Alvin Plantinga’s sense), and neither needs defence, nor can find any. This, it seems to me, should worry Jerry a lot more than it apparently does. As an article of scientific faith, you might almost say that Jerry is here fudging off by degrees into the realm of theology – Ceiling Cat help us! – a space normally occupied by religious believers.
Coyne issued a strongly worded rebuttal:
I don’t think that the principle of determinism “can find no defense.” Nor is it “an article of scientific faith.” Its defense is twofold: it works and, except for actions on the quantum scale, we know of nothing that isn’t predictable in principle. All the progress science has made on the macro scale rests on the idea that given absolutely identical physical conditions acting on an object, its response will always be the same. If this principle didn’t work, we couldn’t get rockets to the Moon. I accept the fact that quantum events, like the location and momentum of electrons or the moment when an atom of a radioactive element decays, can be absolutely unpredictable. But I doubt that this unpredictability has observable results on the scale of human behavior. Physical determinism at the macro level is simply something that works and makes accurate predictions about the universe, and therefore is not an article of faith. My “faith” in determinism of human behavior rests on the same “faith” I have that the origin of life occurred by naturalistic means and not via God. (I put “faith” in quotations marks lest creationists think I mean “unsupported beliefs” that are identical in kind to religious beliefs. I don’t mean that: my “scientific faith” really means “confidence based on experience”.) (Emphases mine – VJT.)
Professor Coyne’s belief in naturalism is therefore based on three specific grounds: first, an extrapolation from past experience (the success science has had in finding naturalistic explanations for events during the past 2,500 years); second, the absence of any “in principle” reason why some kinds of events should be supernatural; and third, the claim that “progress in science” depends on naturalism being true.
My first reaction, on reading Professor Coyne’s justification of naturalism, was that it seemed very emotion-driven. Professor Coyne clearly wants science to succeed in its project of explaining everything according to natural laws. So far, so good: science has managed to explain quite a lot. Second, Coyne can’t see any obvious reason why the successful onward march of science won’t continue. Finally, if it didn’t continue, Professor Coyne would be most upset, for that would be the end of scientific progress. Therefore, science will continue to progress. As Spock would say, “That’s illogical!” On this issue, I would side with Spock and against Coyne. Belief in naturalism is not rational; it’s simply wishful thinking dressed up as science. Now, I realize that this might not seem obvious to some readers, who will see naturalism as a legitimate extrapolation, which is based on the predictive success of science to date. But as the following four points will make clear, it isn’t; it’s a bad extrapolation, which betrays a lack of critical thinking.
The first reason why this kind of extrapolation is unwarranted is that it completely ignores problems of scale. Imagine if I were to argue: “Human beings have managed to travel to many different places in the past, from the Moon to the Marianas Trench. There’s no reason in principle why they can’t travel to the farthest reaches of the cosmos. What’s more, if they didn’t, the progress of exploration would come to a halt. Therefore, I predict that some day, we’ll colonize every nook and cranny of the cosmos.” I don’t think you’d be too impressed with reasoning like that. Why not? Because some places are a lot harder to explore than others – many orders of magnitude more difficult. Getting to the Moon was hard enough: think of the cost of the Apollo program. And now consider the fact that the Moon is less than 400,000 kilometers away, while the nearest star (apart from the Sun) is over 40,000,000,000,000 kilometers away. See what I mean?
“But what does that have to do with naturalism?” you ask. Think of it this way. So far, scientists have managed to explain how amino acids arose naturally on the primordial Earth. But most amino acids contain 10 or fewer carbon atoms. By contrast, an E. coli bacterium (which is a very simple organism) contains about 7,000,000,000 carbon atoms. That’s quite a jump: nearly nine orders of magnitude. Scientist Douglas Axe has recently argued (see here and here) that the natural formation of even a single small functional protein (150 amino acids) on Earth as a result of unguided processes is fantastically unlikely, even over a period of billions of years. Now ask yourself: are you still confident that scientists will one day explain the origin of life?
A second reason why Professor Coyne’s justification of naturalism is flawed is that it is an inductive inference, which can be overturned by a countervailing inductive inference. Coyne might reason: scientists have managed to find naturalistic explanations for many kinds of events in the past, so they’ll probably find naturalistic explanations for the rest in the future. But an Intelligent Design theorist could use inductive reasoning to argue the other way. (Actually, intelligent design reasoning is abductive, which makes it much stronger than inductive reasoning as it invokes the notion of causal adequacy, but we’ll overlook this distinction for now.) The Intelligent Design theorist could argue: “Each and every instance of digital code that I’ve encountered so far has been created by an intelligent agent. Life contains a digital code, so it’s probably the work of an intelligent agent.” He/She might then reason that since the universe has a finite history and was initially lifeless, the intelligent agent that produced the first life is probably outside the cosmos – and, what’s more, it’s probably outside the multiverse as well, since even an inflationary multiverse generator that was capable of generating an enormous number of universes (including ours) would have to be extraordinarily finely tuned, and everything that human beings have encountered so far which has a very high degree of fine-tuning has turned out to have been produced by an intelligent agent. Thus a double inductive inference from Intelligent Design (an inference regarding the origin of life, coupled with an inference regarding the origin of the multiverse) appears to take us to a non-naturalistic explanation for life in the cosmos – which is precisely the opposite conclusion to that arrived at by Coyne’s inductive argument for the eventual success of naturalism. Here’s my question: which inductive inference trumps which? Does Coyne’s naturalism trump the anti-naturalistic argument I described above, or the other way round?
Perhaps Professor Coyne might argue that his inductive inference should over-ride the Intelligent Design theorist’s inductive inference, on the grounds that his is more fundamental: it’s a necessary condition for the advancement of science. Science cannot continue to progress unless naturalism is true. And that brings me to my third point, which I shall pose in the form of a question: is Professor Coyne’s claim, that “progress in science” stands or falls on the truth of naturalism, true by definition? If so, then it’s a question-begging definition by fiat: Coyne might want to define scientific progress in this way, but other scientists might not. Or is Professor Coyne making an empirical claim that scientific progress has always been founded on the assumption that there is a naturalistic explanation for every kind of phenomenon, and that science has been steadily whittling away at the domain of phenomena that resist explanation in scientific terms? In that case, I would have to say that his claim is simply false.
Scientists love to propagate the triumphalistic myth that for the past 2,500 years, science has been steadily expanding the range of phenomena that can be explained in naturalistic terms, while simultaneously reducing the domain of phenomena which defy a naturalistic explanation. But the facts reveal a very different picture. For the reality is that there have been stunning reversals as well as striking successes in the scientific quest to explain the world around us: many phenomena which appeared very easy to account for in ancient times are now known to be much harder to explain than they appear to be. I’ll mention just four: the origin of the universe, the origin of life, the origin of species and the “hard problem of consciousness” (how do brain processes give rise to conscious experiences?) The vast majority of scientists today are Darwinists, who believe that the third problem has finally been solved, after a great deal of intellectual effort; however, the first, second and fourth problems continue to give them headaches. But if we go back 2,300 years, to the time of Aristotle, the general scientific view was that these were not difficult questions. In those days, it was widely believed that the universe was eternal, that life could be generated spontaneously from dead or decaying matter, and that the various species of living organisms had always existed on Earth. Hence the problems of explaining how the universe came into being, or how life originated, or how the various species of living things came into existence, simply did not arise. The hard problem of consciousness didn’t bother philosophers either: neither the ancient Greek scientist Aristotle (384-322 B.C.) nor the medieval Christian philosopher St. Thomas Aquinas (1225-1274 A.D.), who helped disseminate Aristotle’s writings in Europe, betray the slightest hint of puzzlement in their psychological treatises as to how a physical process and a conscious feeling could both be one and the same thing. For instance, Aristotle matter-of-factly defined anger in material terms as “the boiling of the blood and hot stuff round the heart,” while formally characterizing it as “the appetite for returning pain for pain,” in his De Anima, Book I, part 1. Indeed, both Aristotle and Aquinas believed that dead or decaying matter was capable of spontaneously assembling itself into sentient organisms – a belief that now strikes us as ludicrous in its naivete.
Even during the past fifty years, the notion that the supernatural has been retreating from the domain of science is patently false. Fifty years ago, the Steady State theory, which postulated an eternal universe, was still scientifically respectable; nobody had yet put forward the fine-tuning argument for the existence of a cosmic Creator; the success of the Miller-Urey experiment in creating amino acids inspired many scientists to believe that the mystery of life’s origin would soon be solved; and the neo-Darwinian synthesis of 1959 led scientists to believe that the mechanism of evolution was now understood. How things have changed!
As for the notion that scientific progress was based on the assumption of naturalism: history paints a much more complex picture. The ancient Greek scientists and philosophers were, by and large, shy supernaturalists. Plato believed in a self-moved mover and first cause, but the notion of creation ex nihilo never occurred to him, and his universe was formed (not created) by a lesser being: the Demiurge. Aristotle’s universe had a Prime Mover, but one who did not interact with the universe and who remained aloof from human affairs. For Epicurus too, the gods took no interest in mortals. But the European scientists who launched the Scientific Revolution were all devout Christians, and many of them – notably Johannes Kepler, William Harvey, Francis Bacon, John Ray, Robert Boyle and Isaac Newton – explicitly claimed in their writings that science could furnish arguments for the supernatural. What’s more, most of these scientists put forward Intelligent Design-style arguments for the existence of God. (Yes, I can cite chapter and verse, if you want me to.) That’s a much more explicit supernaturalism than that espoused by the ancient Greek philosophers and scientists. More recently, in the last two centuries, there has been a move away from supernaturalism in science. However, a 200-year-trend is a very poor basis for the inflated claim that all scientific progress is built on the rock of naturalism, and as I argued above, the events of the last fifty years suggest that this trend is reversible.
The fourth and final point I’d like to make is that Professor Coyne’s criterion for scientific progress isn’t the only one on the market. I’d like to propose a better one. I would define scientific progress in terms of how accurately scientists can define the limits of what Nature can and cannot accomplish: in other words, what kinds of changes are naturally possible, and what kinds of changes are beyond the power of Nature? My yardstick has the conspicuous advantage of being a quantitative one. It’s also metaphysically neutral. A few examples will serve to illustrate my point.
From physics: we know that it is naturally impossible to transmit information faster than the speed of light, but we don’t know whether it will ever be possible for us to bend the fabric of time and space, or travel through wormholes. We know that it is possible to send people to the Moon and probably the planets, but we don’t yet know whether inter-stellar travel is physically possible for human beings. Another example: we know that natural processes are incapable of creating new energy, if we ignore momentary quantum fluctuations. That’s a fundamental limitation of Nature, which we cannot overcome. On the other hand, we now have the capacity to transform energy in ways that our forebears never dreamed of, until the arrival of the Atomic Age.
From geology: we know that the radioactive clocks we find in the Earth’s rocks tick at the same rate under virtually all conditions which are reproducible in a laboratory. It is not naturally possible to make these clocks tick a lot faster or slower. We also know that the continents move at the rate of a few centimeters a year, and that it is not naturally possible for them to move at the rate of a kilometer a year.
From biology: we know that it is possible for one species to evolve into another; hence species essentialism is false. On the other hand, we also know that nature does not make leaps, and that Goldschmidt’s “hopeful monsters” are a scientific impossibility. Whether new families, orders, classes or phyla of organisms can arise over long periods of time as a result of purely natural processes is still undetermined. (That they arose I do not dispute; the question is how.) Regarding the origin of life, we know that natural processes can generate amino acids from simple organic chemicals, but we also know that making even a simple protein is much, much harder – perhaps too hard a task for Nature alone to accomplish. All scientists would agree, however, that it is totally impossible for inanimate organic matter to transform itself into living organisms (such as animals) within a matter of hours or days, as nearly everyone used to believe until the experiments of Redi in the mid-seventeenth century.
The increasing precision of our knowledge of “the bounds of the possible” is, I would submit, the true measure of scientific progress. We can put a number on what we know, and we make progress as the limits of our uncertainty narrow. Intelligent Design advocate Professor Behe is doing valuable work in researching “the edge of evolution”, and Douglas Axe has recently shown why stepwise processes are naturally incapable of generating proteins in his brilliant essay, The Nature of Protein Folds: Quantifying the Difficulty of an Unguided Search through Protein Sequence Space in The Nature of Nature: Examining the Role of Naturalism in Science, edited by Bruce Gordon and William Dembski, Intercollegiate Studies Institute, 2011. Work like this is helping to show what Nature can and cannot do, in the normal course of events.
I’d like to close with an example of a famous extrapolation in the history of science which was entirely legitimate: Newton’s apple, which prompted Isaac Newton to formulate his theory of universal gravitation. (I’m drawing on Wikipedia here.) John Conduitt, Newton’s assistant at the Royal Mint and husband of Newton’s niece, described the event when he wrote about Newton’s life:
In the year 1666 he retired again from Cambridge to his mother in Lincolnshire. Whilst he was pensively meandering in a garden it came into his thought that the power of gravity (which brought an apple from a tree to the ground) was not limited to a certain distance from earth, but that this power must extend much further than was usually thought. Why not as high as the Moon said he to himself & if so, that must influence her motion & perhaps retain her in her orbit, whereupon he fell a calculating what would be the effect of that supposition. (Conduitt, John. “Keynes Ms. 130.4:Conduitt’s account of Newton’s life at Cambridge”. Newtonproject. Imperial College London. http://www.newtonproject.sussex.ac.uk/view/texts/normalized/THEM00167.)
The article in Wikipedia continues:
The question was not whether gravity existed, but whether it extended so far from Earth that it could also be the force holding the moon to its orbit. Newton showed that if the force decreased as the inverse square of the distance, one could indeed calculate the Moon’s orbital period, and get good agreement. He guessed the same force was responsible for other orbital motions, and hence named it “universal gravitation”.
In supposing that the same force (gravity) explained a falling apple and the orbit of the Moon, Newton was making an intuitive leap spanning several orders of magnitude. The emotionless Spock would probably not have made a leap like that. But Spock would surely have approved of what Newton did next: he did the calculations for the Moon’s orbit and obtained good agreement with the observed results. Newton’s readiness to test his intuitions by performing detailed mathematical calculations and checking them against the real world was what made his extrapolation a warranted one. Now compare this warranted extrapolation with Professor Coyne’s inference to the truth of naturalism, based on the past success of science. The question that leaps to my mind is: where’s the math?
I would invite the reader to contrast Newton’s mathematical rigor with the wishy-washy, hand-waving hypotheses put forward by contemporary biologists in an attempt to naturally “explain” the origin of life, or even of simple proteins, and draw his/her own conclusions.