How to Talk about Science to the Public – 2. Speak Honestly about Uncertainty

Don Howard

We are all Humeans, all of us who are trained in science, at least. We know that empirical evidence confers at most high probability, never certainty, on a scientific claim, and this no matter how sophisticated the inductive logic that we preach. Enumerative induction doesn’t do it. That the sun rose every day in recorded history and before does not imply that it will, of necessity, rise tomorrow. Inference to the best explanation doesn’t do it, for such inferences depend on a changing explanandum (that which is to be explained) and upon both an obscure quality metric (what determines the “better than” metric) and a never complete reference class of competing explanations. Bayes’s theorem can’t do it either.

No. All of us who are trained in science know that every theory, principle, law, and observation is open to challenge and that many once thought secure now populate the museum of dead theories. Sophisticated philosophers of science have invented the intimidating name, “the pessimistic meta-induction” for the thesis that, just as all theories in the past have turned out to be false or significantly limited in scope, so, too, most likely, will our current best and future science.

No. We all know that science is a matter of tentative hypotheses and best guesses. Some principles that have proven their mettle over the long haul, such as the conservation of energy, rightly earn our confidence that they can be reliable guides in the future. But more than one scientist has been willing to sacrifice even the conservation of energy if that were the price to solve another intractable riddle, as when Niels Bohr twice proposed theories that assumed violations of energy conservation.

That science does not deal in certainty is a major part of what makes it such a precious cultural achievement. Science is not dogma. Science admits its failings and learns from its mistakes. That it does so is key to how it achieved the dramatic expansion of scientific understanding that we have witnessed at least since the Renaissance.

Why, then, do we have so much trouble speaking honestly to the public about uncertainty? Why, when debating on the campaign trail, do we give in to the temptation to describe anthropogenic climate change as “proven fact.”? Why, when on the witness stand, do we feel the need to assert that a Darwinian story about human origins is established “beyond all reasonable doubt”? We have lots of good reasons for believing in human-caused climate change and Darwinian evolution. Few scientific claims are as well established as these. But about both we might be wrong in some as yet unforeseen or unforeseeable way. Why lie? Why not speak honestly?

There are at least two reasons why, when speaking to the public, we so often seek refuge in the rhetoric of proof and truth. The first is that we wrongly think that the scientific laity cannot understand uncertainty and probability. This is one of the most worrisome ways in which we insult the intelligence of our audience.

That lots of us – scientists and non-scientists alike – make lots of inductive and probabilistic mistakes is obvious. Casinos, state lotteries, and race tracks are all the evidence one needs. They profit only thanks to those mistakes. Nor are any of us rational utility maximizers, soundly weighing expected gains and losses against the probabilities of various outcomes. The stock market provides the relevant evidence here.

But the fact that lots of people make inductive errors doesn’t imply that the educated public can’t deal with uncertainty. We all deal with uncertainty all the time, and, in the main, we do a good job with it. Do I take I-294 or the Skyway, the Dan Ryan, and the Kennedy to O’Hare? What are the odds of congestion on each at this time of day? How much of a time cushion do I have? What are the consequences of being early or late? How likely am I to miss my flight if there is a ten-minute delay, a twenty-minute delay, or an hour-long delay? Chance of rain? Do I take the umbrella or also my overcoat? Much of life is like this. We make mistakes, but we get by, don’t we?

Naomi Oreskes and Erik Conway. Merchants of Doubt. Bloomsbury Press, 2010.

The second major reason why we retreat to the rhetoric of proof and truth is that we allow ourselves to be intimidated by the merchants of doubt.* The political exploitation of uncertainty to create the illusion of scientific dissensus and thereby stymie policy making on global warming, public health, energy, and other issues is now, itself, big business. There are lobbying firms, fictitious “think tanks,” corporate public relations offices, sham public interest groups, and members of congress who might as well be paid spokespersons. Much of the same kind of apparatus is encountered in the “debates” over evolution and intelligent design. Acknowledge uncertainty, and that becomes the wedge by means of which the illusion of scientific controversy can be created where there is, in fact, no controversy. What is to be done?

What is not to be done is misrepresenting the contingency of science. It is a mistake to confront the merchants of doubt with the pretense of certainty and proof. The right response is to trust the public to understand the weighing of evidence and the adjustment of policy to the strength of the evidence. The right response is, simply and clearly, to present the evidence. To be sure, climate modeling and population genetics involve sophisticated statistical tools that cannot be explained in detail in a few sentences. But with only a bit effort one can usually explain the general issue in an accessible manner.

A good example of making probabilities accessible is the recent reporting on the hunt for the Higgs boson with the Large Hadron Collider at CERN. Any reader of the New York Times or the Wall Street Journal now knows the expressions “three-sigma” and “five-sigma.” A tutorial on calculating standard deviations was not needed to communicate the point that, when sorting through oceans of data, looking for truly exceptional events, one wants to be sure that what one is seeing is more than what would be expected from random fluctuations. People understand this. If the roulette ball lands on 36 twice in a row one is mildly surprised but doesn’t accuse the croupier of cheating. If it lands on 36 five times in a row, then it’s time to ask to see the manager.

No contentious policy questions turn on the results from CERN, so perhaps it is easier for us to speak about uncertainty in this context. But if we can educate the public about statistics in particle physics, surely we can do it as well when the topic is flu epidemics or vehicle safety or climate change. Here is the evidence for increased global temperatures over the last century. Here is what the models predict for increased sea levels. Here is our degree of confidence in these predictions. Now let’s talk about the costs and benefits of different courses of action. Be firm. Be clear. Don’t be afraid to call a lie a “lie” when others misrepresent the evidence or misdescribe the models. But trust the public to follow the logic of the science if we do a good enough job of explaining that logic.

There might be one final reason why we too often retreat to the rhetoric of proof and truth, a reason that I’ll just mention here, saving a fuller discussion for another occasion. It is that too many of us were, ourselves, badly trained in science. Too many textbooks too many courses, and far, far too many popular science writers still teach the science in ways that encourage the illusion of settled fact where there is none. Thomas Kuhn taught us that science teaching often looks more like indoctrination than we might be comfortable acknowledging. There are remedies for this, foremost among them a more thorough and sophisticated incorporation of history and philosophy of science into science pedagogy. But, again, that is a topic for another post.

*See the excellent book by this title: Naomi Oreskes and Eric Conway, Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming (Bloomsbury Press, 2010).

Science and Values – 1. The Challenge for the Philosopher

Don Howard

Science, by which I mean also the technologies that flow from and inform it, is a form of social practice. It has evolved distinct institutions and a distinct sociology. It has accumulated and refined an array of formal techniques and instrumental means for knowledge production and certification. That it is also socially embedded, affected by and affecting every aspect of human life, is a trivial truth. The only question, albeit a large one, is, “How?” By what means, in which respects, and to what extent does science change our world and does the world change science? Some changes are obvious, as with the accelerating transformation of material culture effected by science, and changes in our understanding of self, the worlds our selves inhabit, their relation to one another, and the relation of both to nature and spirit. Other changes, and the manner of the change, are less so, as with the content and modes of production of scientific knowledge. Does it make a difference when science is done in a democracy? Does it make a difference when research is funded by the private sector rather than the state? Is science neutral, objective, and above the fray? Understanding how science affects and is affected by its surround is necessary if we wish to effect intelligent control over science and the part of human life that it touches, which is well nigh the whole of the human experience.

Philosophers of science are supposed to understand the structure, methods, and interpretation of science. But apart from modest progress on the formal side and a few helpful insights in the foundations of some individual sciences, philosophy’s record from the early twentieth century has been, until late, rather spotty. In the main, when it comes to all but the more formal questions, philosophers of science have handed the task to their colleagues in history and sociology. History has given good service. Fans of technical history of science have been a tad disappointed in recent decades, but otherwise the history of science is a thriving field, with an expanding scope and a healthy plurality of approaches. Historians have taught us much about how science works and how it lives in its many contexts. But history remains, for the most part, a descriptive, narrative, or hermeneutic enterprise, deliberately eschewing critique and normativity. We may argue about how good a job the sociologists have done since the advent of the “strong programme” (“strong” = context shapes the content of science, not just its aims and institutions) some thirty plus years ago. Instead let’s thank them for forcing everyone to take the question of context seriously and for unsettling our lazy assumptions about the distinctive superiority of science among other social practices, its objectivity, and its social detachment. Subversion of prejudice is a form of critique, but sociology of science, like history of science, remains a largely descriptive, not critical enterprise.

Which brings us back to the challenge for the philosophers of science, my native tribe. Until late, we have struggled to say much that is helpful about the embedding of science in society because we were in thrall to an ideology of value neutrality and the social detachment of science, wrongly think these to be necessary conditions for scientific objectivity. We used to credit logical positivism for this deep insight into objectivity, citing Hans Reichenbach’s distinction between the “context of justification” and the “context of discovery,” the latter being the dustbin into which history, sociology, and all interesting questions about context were cast, the former being the sandbox in which elite philosophers of science alone were allowed to play. Now we regard such dogma not as insight, but as blindness, and the newer historiography explains it as not just the conclusion of a bad argument but as the discipline’s defensive response to political persecution before (Hitler) and after (Joe McCarthy) the Second World War. Weak inductive evidence for the new historiography is afforded by the fact that, curiously, philosophers of science began to overcome their fear of values talk at about the same time that the Berlin Wall came down.

Today, one is happy to report, everyone is eager to get on the science and values bandwagon. There are conferences, books, anthologies, special issues of journals, albeit, as yet, no prizes. Philosophers of science are eager to learn about science policy. They now invite historians and sociologists to their meetings, and they try hard to be respectful, even as they struggle to figure out exactly how empirical evidence bearing on the actual practice of science is supposed to inform their philosophers’ questions. But that is precisely the problem, for what the philosophy of science still lacks are tools for theorizing the manner and consequences of the social embedding of science.

This is not for want of trying. Our feminist colleagues have been at it for thirty or more years. They have taught us a lot about episodes where science has been more deeply affected by its social embedding – read now its “gendering” – than many of us had or wanted to think. Among them there is a proliferation of analytical frameworks, from feminist empiricism to standpoint theory, difference feminism, and postmodernist feminism, each of which has taught us new ways to query once-settled pieties. Phil Kitcher is probably the most prominent philosopher of science otherwise to have taken the plunge, borrowing ideas from John Rawls to think about the place of science in democracy while holding onto what some think are rather shopworn notions of truth and realism (perhaps also a shopworn notion of democracy). Most interesting to me are those projects that mine the past for fresh insights on science, values, and social embedding, as with Heather Douglas’s re-reading of Richard Rudner, Tom Uebel’s rehabilitation of Otto Neurath, and Matt Brown’s resuscitation of John Dewey (more on all of which anon). New theoretical ideas emerge, thus, from attentive history that is more than mere antiquarianism and rational reconstruction.

Lots of commotion. Still we lack, by my lights, the kinds of theoretical tools needed to answer the “How?” question posed above: “By what means, in which respects, and to what extent does science change our world and does the world change science?” We need a theory of science that integrates the history, philosophy, anthropology, psychology, sociology, and even biology of science and scientists into a comprehensive project. In its critical and reformist aspects this theory of science must learn to be normative not just after the fashion of the inductive logician but also in the way of the political theorist and the moral theorist. Promotion of the common good should be the guiding principle. And it would be fun it if could even be a bit utopian.

The next post will set us on our way with a more specific list of necessary conditions for the possibility of such a theory of science.