We live in extraordinary times for the understanding of science. In May 2010, the prestigious journal Science published a letter signed by 255 members of the US National Academy of Sciences. It began “We are deeply disturbed by the recent escalation of political assaults on scientists in general and on climate scientists in particular. All citizens should understand some basic scientific facts. There is always some uncertainty associated with scientific conclusions; science never absolutely proves anything.”1
But how many laypeople understand what this means and recognize it as a strength rather than a weakness of scientific reasoning? And of course there are always those who are willing to exploit any uncertainty for their own political purposes. “We don’t know what’s causing climate change, and the idea of spending trillions and trillions of dollars to try and reduce CO2 emissions is not the right course for us,” said US presidential candidate Mitt Romney in 2011.2 In the following election cycle, in an interview in which he questioned whether there was really any good evidence for global warming, US Senator Ted Cruz said, “Any good scientist questions all science. If you show me a scientist that stops questioning science, I’ll show you someone who isn’t a scientist.”3 Scarcely a year later, newly elected President Donald Trump said that he wanted to eliminate all climate change research done by NASA, in an effort to crack down on “politicized science.” This would mean an irreparable loss for climate monitoring, not only for the United States but for all researchers the world over who depend on NASA’s legendary satellite-driven data collection about temperature, ice, clouds, and other phenomena. As one scientist from the National Center for Atmospheric Research put it, “[this] could put us back in the ‘dark ages’ of almost the pre-satellite era.”4
The attack on science has now gotten so bad that on April 22, 2017, there was a “March for Science” in six hundred cities around the world. At the one in Boston, Massachusetts, I saw signs that said “Keep Calm and Think Critically,” “Extremely Mad Scientist,” “No Science, No Twitter,” “I Love Reality,” “It’s So Severe, The Nerds Are Here,” and “I Could Be in the Lab Right Now.” It takes a lot to get scientists out of their labs and onto the streets, but what else were they supposed to do? The issue of what’s special about science is no longer purely academic. If we cannot do a better job of defending science—of saying how it works and why its findings have a privileged claim to believability—we will be at the mercy of those who would thoughtlessly reject it.
The aim of this book is to understand what is distinctive about science. Of course, some might say that we don’t need to do this because it has already been done; that the problem is in communicating what is special about science, not understanding it. Don’t we already know what’s special about science by looking at the work of scientists? And, if not, isn’t there plenty of work done by other philosophers of science that can answer this question? I wish this were true, but the fact is that most scientists tend to be “naive realists” who accept their findings as revealing something true (or close to true) about nature and spend little time considering the philosophical or methodological issues behind science as a whole. Those rare scientists who do venture into philosophy usually stumble over something that philosophers have already discovered or end up blasting the whole enterprise as irrelevant because the point—they argue—is not to reflect upon science but to do it.5 Yet that’s just the problem. For all the success of those who have done science, why do so many still feel at a loss to respond with anything other than inarticulate name-calling to those who say that science is “just another ideology” or that we “need more evidence” on climate change? There has to be a better way. Better both to justify the science that has already been done, but also to lay the groundwork for good science to grow elsewhere in the future. But first we must understand what is so special about science as a way of knowing. And for this, many have turned to the philosophy of science.
The foundation of the philosophy of science since its inception has been the idea that it can make a unique contribution by providing a “rational reconstruction” of the process of science, in answer to the question of why science works as well as it does (and why its claims are justified).6 There is a good deal of debate, however, over the best means for doing this and whether it is even a worthy aim. The idea that we can transplant science into other fields by understanding what is most distinctive about it has gotten something of a bad reputation over the years. This notoriety has come from those who have claimed that there is a “scientific method”—or some other firm criterion of demarcation between science and nonscience—such that if we could just apply the standard rigorously enough, good science would bloom as a result. Such claims are made worse by those who embrace the spirit of proselytizing and engage in what has been called “scientism,” whereby they now have a hammer and every other field in the universe of inquiry looks like a nail. But there is a problem: nearly everyone in the philosophy of science these days admits that there is no such thing as scientific method, that trying to come up with a criterion of demarcation is old-fashioned, and that scientism is dangerous.7 Along the way, most have also largely given up on the idea that prescription lies at the heart of the philosophy of science.
Karl Popper’s 1934 model of science Logik der Forschung, translated into English in 1959 by Popper himself as The Logic of Scientific Discovery, focuses heavily on the idea that there is a reliable method for demarcating science from nonscience, but that there is no such thing as a “scientific method.” Popper champions the idea that science uses “falsifiable” theories—ones that are capable at least in principle of being proven wrong by some evidence—as the dividing line. Although this model has several logical and methodological virtues, it has also proven problematic for many philosophers of science, who complain that it is too idealized and focuses too heavily on the “greatest moments” of science, like the transition from the Newtonian to the Einsteinian model in physics, and that most science does not actually work like this.8
Another account was offered by Thomas Kuhn in 1962, in his famous book The Structure of Scientific Revolutions. Here the focus is on how some scientific theories replace others through paradigm shifts, where the scientific consensus changes radically as a result of problems that have built up with the old theory, and the field switches seemingly overnight to a new one. The problem here, however, is not only the familiar complaint that most science does not actually work like this (for instance, the transition from the Ptolemaic Earth–centered model to the Copernican Sun–centered model in astronomy)—which Kuhn freely admits when he talks about the ubiquity of “normal science”—but that even where it does, this is not a completely “rational” process. Although Kuhn insists on the key role of evidence in paradigm change, once we have opened the door to “subjective” or social factors in interpreting this evidence, there seems to be no “method” to follow.9 This not only presents a problem for showing that scientific claims are justifiable, but also forestalls delineating a roadmap for other sciences.
Still further models of scientific change have been proposed by Imre Lakatos, Paul Feyerabend, Larry Laudan, and the “social constructivists,” each of whom drain a little more water from the pool that allows us to say that science is “special” and that other fields of inquiry would do well to follow its example.10 So what to do? Just pick one of the existing accounts? But this is not possible. For one thing, they are largely incompatible with one another; each describes a different piece of the “blind man’s elephant,” so we are still missing a comprehensive picture of what science is like. Another problem is that these models seem to succeed only to the extent that they leave something behind, namely the motivation that if we finally understood science we could provide a standard for other fields to become more scientific.
If all of the best accounts fail, perhaps there is a more general weakness in this whole approach? Although some may be loath to identify it as a weakness, it seems at least a drawback that the philosophy of science has spent so much of its time focusing on the “successes” of science and has not had very much to say about its failures. In fact, the lessons of failure to live up to the scientific standard are as revealing about what science is as the example of those fields that have achieved it. There is nothing wrong in principle with exploring what is distinctive about science by looking at its accomplishments, but this has led to some mischief.
First, while it would be comforting to imagine science as a long series of steps toward the truth—with its failures due only to the wrongheaded and ignorant—this view of science is belied by its history, which is littered with theories that were scientific but just turned out to be wrong. Both Popper and Kuhn have done much to show how science is strengthened by an uncompromising focus on explanatory “fit” between theory and evidence, but it is all too easy for others to look back and pretend that this was all inevitable and that the arc of science bends irrevocably toward a single (true) explanation of reality.
Second, the relentless focus on explaining science through its successes has meant that most of the “victories” that philosophers can turn to for their models have come from the natural sciences. Specifically, we have been forced to draw most of our conclusions about what makes science special from the history of physics and astronomy. But this is a bit like drawing targets around where the darts have landed. And does this mean that in attempting to be scientific, other fields should try to emulate physics? Thinking that the answer to this question is an unqualified yes has done a great disservice to other fields, some of which are solidly empirical but quite different in subject from the physical sciences. Remember that one important part of the mission of the philosophy of science is to understand what is distinctive about science so that we can grow it elsewhere. But where does this leave fields like the social sciences, which until quite recently have been underserved by most of the explanatory models in the philosophy of science?
Popper famously argued that the social sciences could not be sciences because of the “open systems” problem created by the effect of free will and consciousness on human decision making. In natural science, he claimed, we use falsifiable theories, but this path is not open to the social sciences.11 Similarly, Kuhn, for all his fans in the social sciences (who felt that they may finally have a target they could hit), also tried to distance himself from the messy study of human behavior, by insisting that his model was applicable only to the natural sciences, and that he was not providing any advice to the social sciences. Add to this the problem of what to do about some of the other “special” (i.e., nonphysical) sciences—like biology or even chemistry—and we have a full-fledged crisis on our hands in defending a view of science that is separate from reduction to physics. What to do about the claim that there are epistemically autonomous concepts in chemistry (such as transparency or smell)—just as there are in sociology (such as alienation or anomie)—that cannot be explained at the physical level of description? If our model of successful science is physics, will even chemistry make the cut? From a certain perspective, most of those fields that are either scientific, or wish to become so, do not fit the models of philosophy of science that have been drawn from the history of physics and astronomy, and so could be considered “special sciences.” Have we no advice, or justification, to offer them?
Finally, what to say about those fields that make a claim to being scientific, but just do not measure up (such as “intelligent design theory” or denialism about climate change)? Or of those instances where scientists have betrayed their creed and committed fraud (such as Andrew Wakefield’s work purporting to show a link between vaccines and autism)? Can we learn anything from them? I maintain that if we are truly interested in what is special about science, there is much to learn from those who have forsaken it. What is the proponent of intelligent design theory not doing that genuine scientists should do (and in fact generally succeed in doing)? Why are climate change deniers unjustified in their high standards of “skepticism”? And why is it forbidden for scientists to rig their data, cherry pick their sample sets, and otherwise try to fit the data to their theory, if they want to succeed in scientific explanation?12 It may seem obvious to those who defend and care about science that all of the above have committed a mortal sin against scientific principles, but shouldn’t this help us in articulating the nature of those principles?
In this book, I propose to take a very different approach from my predecessors, by embracing not only the idea that there is something distinctive about science, but that the proper way to understand it is to eschew the exclusive focus on the successes of natural science. Here I plan to focus on those fields that have failed to be scientific, as well as those (like the social sciences) that might wish to become more so. It is one thing to discern what is distinctive about science by examining the transition from Newton to Einstein; it is another to get our boots muddy in the questions of scientific fraud, pseudoscience, denialism, and the social sciences.
Why bother? Because I think that to truly understand both the power and the fragility of science we must look not just at those fields that are already scientific, but also at those that are trying (and perhaps failing) to live up to the standard of science. We can learn a lot about what is special about science by looking at the special sciences. And we should be prepared to answer the challenge of those who want to know—if science is so credible—why it does not always provide the right answer (even in the natural sciences) and sometimes fails. If we can do this, we will not only understand what is distinctive about science, we will have the tools necessary to emulate its approach in other empirical fields too.
But there is another problem: we cannot pretend, these days, that the conclusions of science are going to be accepted just because they are rational and justified. Climate change skeptics insist that we need more evidence to prove global warming. Vaccine resisters maintain that there is a conspiracy to deny the truth about autism. What should we do about the problem of those who would simply reject the results of science? We may be tempted to dismiss these people as irrational, but we do so at our peril. If we cannot provide a good account of why scientific explanations have a superior claim to believability, why should they accept them? It’s not just that if we don’t understand science we cannot cultivate it elsewhere; we cannot even defend science where it is working.
In short, I think that many of those who have written about science have mishandled the claim that science is special because they have not said enough about the failures of natural science, the potential for the social sciences, and the drawbacks of those fields that seek the mantle of science without embracing its ethos. This has led to failure to emulate science by those fields that would like to do so, and also to the irrational rejection of scientific conclusions by those who are motivated by their ideologies to think that their own views are just as good.
So what is distinctive about science? As I hope to show, what is most notable is the scientific attitude toward empirical evidence, which is as hard to define as it is crucial. To do science we must be willing to embrace a mindset that tells us that our prior beliefs, ideologies, and wishes do not matter in deciding what can pass the test of comparison with the evidence. This is no easy thing to mark off with a criterion of demarcation—neither does it pretend to be a proxy for “scientific method”—but I argue that it is essential to engaging in (and understanding) science. This is something that can be emulated by the social sciences and also helps to explain what is not scientific about intelligent design theory, the emptiness of denialism by those who wish to reject the evidence for climate change, and the folly of other conspiracy theories that purport to succeed where science is restrained by bona fide skepticism. At its heart, what is distinctive about science is that it cares about evidence and is willing to change its theories on the basis of evidence. It is not the subject or method of inquiry but the values and behavior of those who engage in it that makes science special. Yet this is a surprisingly complex thing to unravel, both in the history of the past successes of science and also in a program for how to make other fields more scientific in the future.
In the chapters to follow, I will show how the scientific attitude helps us with three main tasks: understanding science (chapters 1 through 6), defending science (chapters 7 and 8), and growing science (chapters 9 and 10). When done right, the philosophy of science is not just descriptive or even explanatory, but prescriptive. It helps to explain not just why science has been so successful in the past, but why evidential and experimental methods have so much potential value for other empirical fields in the future. It should also help us to communicate more clearly to those who do not—or will not—understand what is distinctive about science, why the claims of pseudoscience and denialism fall so far short of its epistemic standards, and why scientific explanations are superior. For decades, philosophers of science have sought to understand what is special about science by focusing on the past successes of the physical sciences. My approach, instead, is to turn this on its head: if you really want to understand why science is so special, you must look beyond the victories of natural science, and focus too on those fields that are not—and may never become—sciences.