The issue of God is an issue on which reasonable people may differ, but I certainly think it’s an over-statement of our scientific knowledge and understanding to argue that science in general, or evolutionary biology in particular, proves in any way that there is no God.
An alternative form of this argument is to claim that “the absence of evidence [for God] isn’t evidence of [God’s] absence.”
Well, of course, if by “proof” you mean “absolute, unchangeable proof” (or in this case “absolute disproof”), Jacoby and Miller are right. Our understanding of reality—science’s “truth”—is always provisional, and we can never rule out some kind of deity with absolute certainty.
But you can “disprove” God’s existence in another way, by making two assumptions. First, the god under scrutiny must be theistic—one who has certain specified traits and interacts with the world. If you posit a deistic god who doesn’t do anything, or a nebulous “Ground of Being” god lacking defined traits, then, of course, there’s no way to get evidence either for or against it. But that also means there’s no reason to take it seriously either, for assertions lacking evidence can be dismissed without evidence.
Second, we must construe “proof” not as absolute scientific proof, but in the everyday sense of “evidence so strong you would bet your savings on it.” In that sense, we can surely prove that there’s no God. This is the same sense, by the way, in which we can “prove” that the earth rotates on its axis, that a normal water molecule has one oxygen and two hydrogen atoms, and that we evolved from other creatures very different from modern humans.
With the notion of a theistic god and a vernacular notion of “proof” in hand, we can disprove a god’s existence in this way: If a thing is claimed to exist, and its existence has consequences, then the absence of those consequences is evidence against the existence of the thing. In other words, the absence of evidence—if evidence should be there—is indeed evidence of absence.
A famous example of this argument is Carl Sagan’s chapter “The Dragon in My Garage” in his book The Demon-Haunted World. Someone claims that there’s a fire-breathing dragon in his garage. The skeptic’s demand for evidence is then met with a series of evasions: the dragon is invisible, so you can’t see it; it floats, so you can’t detect its footprints in scattered flour; its fire isn’t hot, so you can’t feel its breath. Eventually, says Sagan, the rational course is to reject the dragon’s existence until some evidence actually surfaces. His point was that the “you can’t prove nonexistence” claim is fatuous when the evidence should be there. As he notes at the end of his parable:
Once again, the only sensible approach is tentatively to reject the dragon hypothesis, to be open to future physical data, and to wonder what the cause might be that so many apparently sane and sober people share the same strange delusion.
This was clearly aimed at both pseudoscience and religion, for Sagan was a stronger opponent of faith than most people recall.
We can in fact prove many negatives. Can you prove that I don’t have two hearts? Of course you can: just do a CAT scan. Can you prove that I don’t have a brother? For all practical purposes, yes: just dig through birth records, ask people, or observe me. You won’t find any evidence. Can you prove that I didn’t write Ulysses? Of course: I wasn’t alive when it was published. Can you prove that leprechauns don’t live in my garden? Well, not absolutely, but if you never see one, and they have no effects, then you can provisionally conclude that they don’t exist. And so it is with all the fanciful features and creatures we firmly believe don’t exist.
Many gods claimed to exist should have observable effects on the world. The Abrahamic God, in particular, is widely believed to be omnibenevolent, omnipotent, and omniscient. Some also believe that he gives us an afterlife in which we find either eternal bliss or torment, that he answers prayers, and that he had a divine son who can bring us salvation. If these claims are true, there should be evidence for them. But the evidence isn’t there: we see no miracles or miracle cures in today’s world, much less any wondrous signs of a God who presumably wants us to know him; scientific tests of prayer show that it doesn’t work, ancient scriptures show no knowledge of the universe beyond that available to any normal person who was alive when the texts were composed; and science has disproved many of the truth claims of scripture. Finally we are left with that nagging problem of evil: why would a loving and all-powerful God inflict “natural evil” on the world—allowing thousands of innocent people to die from physical disasters like tsunamis, earthquakes, and cancer?
Putting all this together, we see that religion is like Sagan’s invisible dragon. The missing evidence for any god is simply too glaring, and the special pleading too unconvincing, to make its existence anything more than a logical possibility. It’s reasonable to conclude, provisionally but confidently, that the absence of evidence for God is indeed evidence for his absence.
Science Is Based on Faith
I often hear that science, like religion, is actually based on faith. This argument smacks a bit of desperation, a tu quoque response by beleaguered believers. But it also stems from postmodernism’s view that even in science, truth is a fungible commodity, with different and incompatible assertions carrying equal weight. As we’ll see, the “based on faith” argument against science is purely semantic, resting on two different usages of the word “faith,” one religious and the other vernacular.
The surprising thing is that the claim of faith-based science often comes from scientists themselves. Here, for instance, are three religious scientists who argue that accepting the laws of nature is a form of “faith.” The first is from the physicist Karl Giberson and the physician and geneticist Francis Collins:
Finally, we note that it requires a certain level of faith to answer the scientific questions of how something happens. Answers to scientific questions assume that the laws of the universe are constant or, if recent speculations turn out to be true, the laws are changing in only the most subtle ways. This requires faith in the orderliness of nature. With or without belief in an ultimate creator, we must have faith that this universal order is real, reliable, and accessible to the limited powers of our minds.
The physicist Paul Davies makes a similar claim:
Clearly, then, both religion and science are founded on faith—namely, on belief in the existence of something outside the universe, like an unexplained God or an unexplained set of physical laws, maybe even a huge ensemble of unseen universes, too. For that reason, both monotheistic religion and orthodox science fail to provide a complete account of physical existence. . . . But until science comes up with a testable theory of the laws of the universe, its claim to be free of faith is manifestly bogus.
Sometimes “faith in science” is meant not just as belief in physical laws, but as blind deference to authority: an unthinking acceptance of the conclusions of scientists in other fields or, if you’re a layperson, of scientists in general. This argument was made in, of all places, the pages of Nature, one of the world’s most prestigious scientific journals. Here Daniel Sarewitz, director of a science and policy think tank, sees belief in the Higgs boson, a particle whose field gives mass to all other particles, as an “act of faith” resembling the superstitions of Hinduism:
If you find the idea of a cosmic molasses that imparts mass to invisible elementary particles more convincing than a sea of milk that imparts immortality to the Hindu gods, then surely it’s not because one image is inherently more credible and more “scientific” than the other. Both images sound a bit ridiculous. But people raised to believe that physicists are more reliable than Hindu priests will prefer molasses to milk. For those who cannot follow the mathematics, belief in the Higgs is an act of faith, not of rationality.
A political science professor at Rutgers University argues that “faith” is often imputed to those of us who rely on Western medicine and its authorities—doctors and medical researchers:
I’m not a biologist; I have never actually seen a microbe in person. But I believe in them. Likewise, I take it on faith when my doctor tells me a particular medication will work in a particular way to address a particular malady.
Finally, the theologian John Haught asserts that the faith of scientists has no philosophical basis: you can’t use science itself to show that science is the best way—or even the only way—to discover truths about the universe.
There’s the deeper worldview—it’s a kind of dogma—that science is the only reliable way to truth. But that itself is a faith statement. It’s a deep faith commitment because there’s no way you can set up a series of scientific experiments to prove that science is the only reliable guide to truth. It’s a creed.
Let’s start with the last view, one often raised by philosophers (the argument is called “justificationism”). As a professional scientist, I have always been puzzled by this criticism. It sounds quite sophisticated, and in fact it’s technically correct: science cannot justify by reason alone that it’s the surest route to truth. How can you prove from philosophy and logic alone that scientific investigation, rather than, say, revelation, is the best way to determine the sequence of a newly discovered gene? There’s no a priori philosophical justification for using science to understand the universe.
But we don’t need one. My response to the “no justification” claim is that the superiority of science at finding objective truth comes not from philosophy but from experience. Science gives predictions that work. Everything we know about biology, the cosmos, physics, and chemistry has come through science—not revelation, the arts, or any other “way of knowing.” And the practical applications of science, channeled into engineering and medicine, are legion. Many older readers would, like me, be dead were it not for antibiotics, for until these drugs were discovered in the twentieth century, infection was surely the main cause of mortality throughout the evolution of our species. Science has completely eradicated smallpox and rinderpest (a disease of cattle and their wild relatives), is on the way to wiping out malaria and polio, and produced the Green Revolution, saving millions of lives by improving crops and agricultural methods. Every time you use a GPS device, a computer, or a cell phone, you’re reaping the benefits of science. In fact, most of us regularly trust our very lives to science: when you have an operation, when you fly in an airplane, when you get your children vaccinated. If you were diagnosed with diabetes, would you go to the doctor or consult a spiritual healer? (I’m appealing to our solipsism here by emphasizing how science has improved human welfare, but most scientists are involved less with helping humanity than with satisfying their own curiosity. After all, our big brains, fueled with food, are still hungry for answers. How old is the universe? How did Earth’s species get here? Science alone has given the answers.)
In the end, it may smack of circularity to use empirical results to justify the use of the empirical toolkit we call “science,” but I’ll pay attention to the circularity argument when someone comes up with a better way to understand nature. Science’s results alone justify its usefulness, for it is, hands down, the single best way we’ve devised to understand the universe. And by the way, if you’re going to use the circularity argument against science, you can just as easily apply it to religion. Just as you can’t use the Bible as the authority on the divine truth of the Bible, so you can’t use philosophy—or any “truth-seeking” method of religion—to show that revelation is a reliable route to the truth.
As for the claim that science is a kind of “faith” because it rests on untestable assumptions, depends on authority, and so on, this involves either a deliberate or an unconscious conflation of what “faith” means in religion versus what it means in everyday life. Here are two examples of each usage:
“I have faith that because I accept Jesus Christ as my personal savior, I will join my late wife in heaven.”
“I have faith that when I martyr myself for Allah, I’ll receive seventy-two virgins in paradise.”
“I have faith that the day will break tomorrow.”
“I have faith that taking this penicillin will cure my urinary tract infection.”
Notice the difference. The first two statements exemplify the religious form of “faith,” the one Walter Kaufmann defined as “intense, usually confident, belief that is not based on evidence sufficient to command assent from every reasonable person.” There is no evidence beyond revelation, authority, and sacred books to support the first two statements. They show confidence that isn’t supported by evidence, and most of the world’s believers would reject them.
In contrast, the second two statements rely on empirical evidence—strong evidence. In these cases the word “faith” doesn’t mean “belief without much evidence,” but “confidence based on evidence” or “an assumption based on performance.” You have “faith” that the Sun will rise tomorrow because it always has, and there’s no evidence that the Earth has stopped rotating or the Sun has burned out. You have faith in your doctor because presumably she has treated you successfully in the past and has a good reputation. After all, would you go to a doctor who was constantly being sued for malpractice, or had repeatedly failed to help you? If you had “faith” in your doctor in the religious sense, you’d assume she could do no wrong, no matter what wonky things she’d do or prescribe. If she prescribed toad’s blood for your psoriasis, you’d take it gladly. But the kind of faith we really have in our doctor is a provisional and evidence-based one—the same kind of “faith” we have in scientific results. After a vigorous but unhelpful regime of toad’s blood, you’d find another doctor.
The conflation of faith as “unevidenced belief” with its vernacular use as “confidence based on experience” is simply a word trick used to buttress religion. In fact, you’ll almost never hear a scientist using that vernacular in a professional role, saying things like “I have faith in evolution” or “I have faith in electrons.” Not only is such language alien to us, but we also know full well how those words can be misappropriated by the faithful.
What about the respect that the public and other scientists have for scientific authorities? Isn’t that like religious faith? Not really. When Richard Dawkins talks about evolution and Carolyn Porco about space exploration, scientists in other disciplines accept what they have to say, and the public eagerly consumes their popular books. But that too is based on experience—perhaps not direct experience in the case of the public, but on our understanding that Dawkins’s expertise in evolution and Porco’s in planetary science have been continuously vetted and accepted by hypercritical scientists.
We know too that the self-correcting nature of science and its tradition of affording more respect to accomplishment than to authority (a common saying is “You’re only as good as your last paper”) ensure that an incompetent or ham-handed scientist won’t gain respect—at least for long. Very few laypeople understand Einstein’s theories of relativity, but they know that those theories passed muster with qualified scientists. It was for this reason that Einstein was revered by the public as a great physicist. When Daniel Sarewitz claimed that “belief in the Higgs [boson] is an act of faith, not of rationality,” and compared it to Hindu belief in a sea of milk, he was simply wrong. There is solid evidence for the existence of the Higgs, evidence confirmed by two independent teams using a giant particle accelerator and rigorous statistical analysis. But there isn’t, and never will be, any evidence for a Hindu sea of milk.
In contrast, how reasonable is it to believe that the pope really is infallible when he speaks ex cathedra, or that his views about God are closer to the truth than those of any ordinary priest? A rabbi may gain repute for great kindness or wisdom, but not because he’s demonstrated a knowledge of the divine that is more accurate than that of other rabbis. What he may know more about is what other rabbis have said. As my friend Dan Barker (a Pentecostal preacher who became an atheist) once quipped, “The
ology is a subject without an object. Theologians don’t study God—they study what other theologians have said.” The claims of a priest, a rabbi, an imam, or a theologian about God have no more veracity than anyone else’s. Despite millennia of theological lucubrations, we know nothing more about the divine than we did a thousand years ago. Yes, there are religious authorities, but they aren’t equivalent to scientific authorities. Religious authorities are those who know the most about other religious authorities. In contrast, scientific authorities are those who are best able to understand nature or produce credible theories about it.
As we’ve seen, scientists give no special credence or authority to books either, except insofar as they present novel theory, analysis, or data. In contrast, many creeds require believers and ministers to swear adherence to unchanging doctrines like the Nicene Creed, and many Christian colleges have “statements of faith” that must be affirmed yearly by faculty and staff. This distinction, and the fallacy of claiming that science is a religion, was emphasized by Richard Dawkins in an article in the Humanist:
There is a very, very important difference between feeling strongly, even passionately, about something because we have thought about and examined the evidence for it on the one hand, and feeling strongly about something because it has been internally revealed to us, or internally revealed to somebody else in history and subsequently hallowed by tradition. There’s all the difference in the world between a belief that one is prepared to defend by quoting evidence and logic and a belief that is supported by nothing more than tradition, authority, or revelation.
Scientists, then, don’t have faith—in the religious sense—in authorities, books, or unevidenced propositions. Do we have faith in anything? Two other objects of scientific faith are said to be physical laws and reason. Doing science, it is said, requires faith not only in the “orderliness of nature” and an “unexplained set of physical laws,” but also in the value of reason in determining truth.
Faith Versus Fact : Why Science and Religion Are Incompatible (9780698195516) Page 27