The Scientific Attitude

by Lee McIntyre

  Another denialist misunderstanding occurs over how scientists reach consensus. Again, one does not need 100 percent agreement before the field moves on. Those who are asking for complete agreement among the world’s scientists before something is done about climate change are just running out the clock. According to the latest statistics, over 96.2 percent of the world’s climate scientists believe that climate change is occurring and that humans are responsible for it.43 For comparison, note that a similar survey found that only 97 percent of scientists believe in evolution by natural selection, which is a bedrock principle of biology.44 More than one hundred and fifty years after Darwin, we still do not have 100 percent agreement even on evolution! But we don’t need it, because that is not how scientific consensus works. Scientific claims are subjected to group scrutiny and criticism and, despite inevitable dissent, the field makes a choice.45 Some may complain that this still leaves room for doubt and that the “skeptics” could be right (as they sometimes are), but I wouldn’t hold out much hope for denialism about climate change. For one thing, legitimate dissenters must be able to present some empirical evidence as reason for their dissent. Without that, one questions whether they are even scientists. Denialists might complain that they do have evidence and that they are members of a community, yet this is simply tiresome. As we’ve seen, seeking out a community for mutual agreement is not the same thing as seeking out critical scrutiny. No matter how many people you get to agree with you, majority opinion does not trump evidence in a factual matter.46

  Couldn’t the scientists nonetheless be wrong? Yes, of course. The history of science has shown that any scientific theory (even Newton’s theory of gravity) could be wrong. But this does not mean that one is a good skeptic merely for disbelieving the well-corroborated conclusions of science. To reject the cascade of scientific evidence that shows that the global temperature is warming, and that humans are almost certainly the cause of it, is not good reasoning even if some long-shot hypothesis comes along in fifty years to show us why we were wrong. Skepticism is in complete conformity with the scientific attitude’s commitment to form one’s beliefs based on fit with the evidence, and then change them as better evidence comes in, but this in no way guarantees truth. Science instead offers justification based on the evidence. Yet this is a mighty thing. With denialism, one decides in advance—on the basis of ideology—what one wants to be true, then selectively filters information based on whether it supports the hypothesis or not. But this does not build warrant. Science may sometimes miss the mark, but its successful track record suggests that there is no superior competitor in discovering the facts about the empirical world.

  Indeed, this is why someone like Galileo was not a denialist. Who claimed that he was? In an interview with the Texas Tribune in March, 2015, Ted Cruz said:

  Today the global warming alarmists are the equivalent of the flat-Earthers. It used to be … accepted scientific wisdom the Earth is flat, and this heretic named Galileo was branded a denier.47

  We can make pretty short work of this claim. Galileo believed in the heliocentric model not because of ideology but because of evidence. His telescopic observations of the phases of Venus, craters on the Moon, and the satellites of Jupiter provided a mountain of reasons for believing that the Ptolemaic model of an Earth-centered universe was wrong, and it should have convinced anyone who doubted him. The Catholic Church was the one with ideological beliefs that prevented them from accepting the reality of Galileo’s evidence because of what it would have meant for their celestial model. Galileo most certainly was not a denier. To deny the truth of a false theory when you have the evidence to show that it is false is not denialism; it is science.

  What might happen when the lone dissenter does have the evidence? When that person questions the established consensus of science and shows that it is wrong? This challenges the idea that science is a privileged process resulting from group scrutiny of individual work. Can the scientific attitude survive intact if someone goes against the scientific community—which is supposed to be the final arbiter of justificatory warrant—and wins?

  What Happens When the “Crank” Is Right?

  J Harlen Bretz was a maverick geologist in the early twentieth century, who spent a long career at the University of Chicago, but did his fieldwork in a desolate region of Washington state that he termed the “channeled scablands.” This area is remarkable for its severe “Mars-scape” surface, consisting of washed-out channels surrounded by high bluffs (where gravel and “erratic rocks” are found thousands of feet above sea level), U-shaped canyons with dry falls, and enormous plunge pools with only small waterfalls draining into them. It is, in short, a geography that demands an explanation.

  This area had not been well studied before Bretz, but geologists of the time did have their hypotheses. Most agreed that this landscape had been carved by hydrologic forces, but—in keeping with the “uniformitarian” theory of the time—they thought that this must have been the result of relatively small amounts of water acting over long periods of time, such as those that had created the Grand Canyon. Uniformitarianism, which had been the dominant paradigm in geology at least since Charles Lyell’s influential textbook (which inspired Darwin’s theory of evolution by natural selection) is the idea that the geological record can be explained by known natural forces acting over millions of years.48 This was proposed in contrast to the catastrophism of Lyell’s predecessors, who felt that short-term cataclysmic events—perhaps caused by God—had created the geological, fossil, and biological record. Natural forces versus miracles. Erosion versus a catastrophe. It was not hard to figure out which side most scientists would be on.

  Although Bretz was himself a uniformitarian (and an atheist), as he stood before the scarred, barren landscape for the first time in 1921, he began to realize that the prior theories must be wrong. Like a detective solving a mystery, Bretz found too many clues that this could not have been the result of steady erosion. What was the alternative? A massive flood. A flood so large that it would have been thirteen miles wide at some points and involved a volume of water so strong it could force the Snake River to flow backward, make U-shaped channels rather than V-shaped ones as far south as the Columbia Gorge, put the “turtle on the fencepost” of gravel found on top of 2,500-foot-high bluffs, and create the enormous plunge pools that were so disproportionate to the tiny falls that fed into them. Where could such an enormous amount of water have come from? Bretz did not know and, for the moment, he framed no hypotheses. It was a puzzle and he vowed merely to follow the evidence wherever it landed him. By the time he came back for the second summer to continue his fieldwork, he was convinced:

  Bretz now believed that these geologic features could only have been created by a flood of unimaginable proportions, possibly the largest flood in the history of the world. And this was no claim made as wild speculation. Fact after fact, feature after feature in the landscape had proven to Bretz that his theory provided the only plausible answer for the formation of the channeled scablands.49

  The story of Bretz’s work is a fascinating and under-reported topic in the history and philosophy of science, which would repay much greater scholarly attention. John Soennichsen’s Bretz’s Flood is one of the few available resources, but fortunately it is wonderful, both for telling the story of Bretz’s struggles but also providing the intellectual context of the time with discussion of geological positivism, uniformitarianism versus catastrophism, the struggle to make geology more scientific, and how sociological factors can influence scientific explanations. Here I will focus on the narrow issue of what implications Bretz’s story might have for the scientific attitude, when group consensus is against the individual who is right and has the evidence. Does this challenge the idea that the scientific attitude is instantiated at the level of group practice and that science works primarily because the community of scientists corrects the errors of individuals? As I hope to show below, I think that the Bretz episode not only survives thi
s challenge but is in fact a stunning demonstration of the power of the scientific attitude.

  It is obvious that Bretz’s work is an endorsement of the scientific attitude at the individual level. He gathered enormous amounts of evidence to back up his hypothesis and critiqued and shaped his theory along the way. Because his theory was in some ways a throwback, he understood that it would be savagely attacked.50 Bretz did not posit any supernatural forces to explain the geological record, but neither could he explain it with currently existing forces acting over a long period of time that uniformitarianism demanded. Instead, he had to propose an enormous catastrophic event that had occurred over a short period, with an unknown source of water. It would sound like something out of the Bible; the push back would be tremendous.

  Geology, like other sciences, is a brotherhood of sorts, with much camaraderie and the sharing of data, ideas, and facilities. It is seen as a field in which the work of one individual can inspire another, and through the cooperation of all, fledgling theories can expand and flower into fully matured scientific views shared by the discipline as a whole. As with other brotherhoods, however, squabbles can erupt and family members who don’t adhere to the basic rules can be verbally disciplined or—perhaps worse—ignored altogether.51

  What Bretz was proposing sounded like heresy. To Bretz’s credit, he didn’t seem to care; he had the evidence and knew he was right. The others would just have to come around. In this, Bretz reminds one of a modern-day Galileo.52 Those who fought him had not done the fieldwork or seen the landscapes.53 Bretz was stubborn enough to believe in the implications of what he had seen firsthand, and if it did not square with current theories, then those theories must be wrong. This is good testament to Bretz’s adherence to the scientific attitude, but there was trouble ahead.

  One problem for Bretz was that he still had no idea what could have caused such a megaflood. The amount of water required would be tremendous. He would be telling a causal story with no cause in sight, and he knew this would present a formidable barrier to acceptance of his theory. But the geologic record simply demanded that amount of water. Here Bretz also reminds one of Darwin, who gathered evidence that supported his theory of evolution by natural selection long before he had any idea of the mechanism that might be behind it. One is also reminded of Newton, who “framed no hypothesis” about what gravity was, as he worked out the equations that described its behavior.

  It’s important here to pause and consider the implications for the scientific attitude, because it reveals that understanding a cause is not necessary for scientific explanation. Causal explanations are an important part of complete scientific theories, and positing a miracle is not an acceptable substitute. But most important is having evidence that a hypothesis is warranted; cause can be inferred later. This is not to trivialize causal explanation. It’s just that finding a cause is often the last part of scientific explanation, coming into place after all of the other pieces of evidence have been gathered and fit together.

  In Bretz’s case, it would have been preferable if he had known a cause, but initially he simply could not specify one, so he stuck to his evidence from the geologic record. Note that Bretz was enormously self-critical and made numerous corrections and modifications to his theory as he went along.54 This was nothing, however, compared to the criticism he was to receive at the hands of his fellow scientists.

  In 1927, Bretz stood on the steps of the Cosmos Club in Washington, DC, to present his evidence before a gathering of the nation’s most distinguished geologists. Foremost among these were six members of the US Geological Survey (USGS), who were a sort of governing board for the profession. Bretz gave a lengthy, definitive, presentation based on his six years of fieldwork in the area. Then, when it came time for the respondents to speak, “all hell broke loose.”

  One by one, each of the men sitting at the presentation table rose to confront him with objections, criticisms, and—for the first time—their own interpretations of the scablands. It quickly became clear that this had been a planned attack; a strategic event that allowed Bretz to offer his views, then be subjected to the collective bile of virtually every prominent geologist of his time. … It seems clear that the official stance of that influential body was one of intolerance for any theory that strayed from the uniformitarian line.55

  This, of course, is not how science is supposed to work. Looking back, one suspects that the learned scientists were objecting to Bretz’s theory because of motivated reasoning rooted in a near-ideological commitment to uniformitarianism. It is one thing to attack a theory based on lack of fit with the evidence; it is another to say that it cannot be tolerated because it would erode the field’s hard-won progress in distancing itself from religious views that would keep it from being seen as scientific.

  In this book, I have made the case that the scientific attitude is instantiated not just in the values of individual scientists, but in the community of scholars. So what can be said about a case where the “heretic” is behaving more scientifically than his critics? Is it possible to defend the importance of the scientific attitude even when the consensus of one’s profession is wrong? This is a delicate question, for although it is common for individual scientists sometimes to outpace the group—indeed, this is often how breakthrough ideas come to disseminate and lead to a changed understanding—what is rare is for someone to openly contradict the scientific consensus for decades and later be vindicated. Great historical examples of this include Galileo, Semmelweis, Alfred Wegener, and other martyrs for science. But when such episodes occur, what is the guidepost for keeping science on track? It has to be the evidence. It’s not that Bretz was making some wild claim out of the blue: he had the evidence to back it up. So even while it is understandable that there will sometimes be community resistance to those are perceived to have departed from orthodoxy in their scientific thinking, over time this conflict must be resolved in the only way possible in science: through empirical evidence.

  And this was in fact precisely what occurred with Bretz’s theory of the channeled scablands. After the disastrous Cosmos Club talk, one of Bretz’s previous rivals helped him to realize that the only water source big enough for such a massive flood must have been the spontaneous draining of a glacial lake. This turned out to be the right answer. It is now thought that the failure of a giant ice dam at Lake Missoula released over 500 cubic miles of water that reached 100 miles south of Portland, Oregon.56 Still the detractors held on.

  The geologic community went about their business and tried to ignore the fact that this upstart geologist was spouting nonsense about massive floods he claimed had altered the topography of a vast western landscape in a geologic blink of an eye.57

  Bretz went into a deep depression. As time passed, some of his critics eventually died, while others came around, but a new generation of geologists also grew up who were more sympathetic to Bretz’s theory.58 After decades, Bretz was eventually vindicated. As one of his critics said years later when he finally visited the scablands himself, “How could anyone have been so wrong?”59 How sweet it must have been in 1965 when a group of geologists made an official field trip to the scablands and sent Bretz this telegram: “We are all catastrophists now.”60

  In a strange coda to Bretz’s story, his legacy has now been claimed by thousands of creationists, who regard him as a sort of folk hero for almost single-handedly proving their case for a biblical flood. Of course, Bretz did no such thing, yet there are creationist websites on which he is celebrated as a David who went up against the organized science Goliath and won.61 What to say about this? And does Bretz’s example give support to the idea that someone like Ted Cruz just may be the next Galileo? This seems preposterous; remember that the lodestar in Bretz’s story is one of sticking to the evidence and eschewing ideology. If a science denier claims that climate change is a hoax, where is the evidence? Without this, it is just speculation or worse. This is not to say that simple skepticism or even stubbornness marks a dep
arture from science. The standards for accepting a new theory should be high. But when a scientist abandons evidence for ideology, this is no longer science.

  What might happen if a purportedly crackpot theory did have the evidence? Then it must be tested and, if it holds up, the scientific consensus must change. Just as the scientific attitude should ideally guide individual behavior, so too it must guide group behavior. Science is supposed to be self-correcting at both the individual and the group level. Imagine a scientist with an outlier theory that did not square with the evidence and was rejected by the rest of the profession. If this scientist clings to the theory, in some sense he or she will have left the profession. Can the same thing happen to an entire discipline? Although it is more commonly the case that the group corrects the individual—as in the case of cold fusion—it does sometimes occur that the individual corrects the group.

  Just as geology was temporarily taken off course by refusal to accept Alfred Wegener’s theory of continental drift, so it was later to suffer the same fate with Bretz’s theory of the channeled scablands. It is painful to think that geology was “not scientific” for a time, but that is as it must be when scientists refuse to change a theory in the face of compelling evidence. Just as the Catholic Church refused to acknowledge the truth of Galileo’s new theory of the heavens—choosing instead to stick with its familiar but false ideology—so for a time did geology choose to embrace strict uniformitarianism over empirical evidence.62 What makes science distinctive, however, is that even when this occurs, there is a way to get back on track.63 Indeed, note that—as a science—geology did eventually recognize the force of Bretz’s data, and return to the scientific attitude. (The Catholic Church, however, did not and was instead humiliated into an apology to Galileo 350 years after it had already lost the debate over heliocentrism.)