Uncertain science

Sometimes it is impossible for science to produce certain knowledge about matters upon which we would dearly love to have definite answers. Consider the challenge that the Environmental Protection Agency faces in setting exposure limits in water supplies for substances known or strongly suspected of being carcinogenic . The concentrations of such substances in a water supply are typically very low, in the parts per million range. Still, such low levels could be harmful, at least to a fraction of people. We can’t get all of the carcinogen out of the water, but we could reduce its concentration at some cost. At what level of concentration would a particular carcinogen be expected to cause no more than a certain very low level of added cancer, and what would it cost to get to that level? Toxicologists can’t do useful experiments on test animals with the water as it is found, because at the low concentrations of pollutant, it would take a huge number of test animals to produce a statistically meaningful result. Instead, what is done is to use much higher concentrations of the pollutant in the laboratory, much greater than would ever occur in the natural situation, with a manageable populations of animals. Various concentrations of the carcinogen are used with groups of test animals, and the incidence of excess cancers is monitored after a period of using those levels. A graph is then constructed of excess cancers vs. the concentration used. We might then get the red data points, as shown in the figure above.

All the investigator sees of course are the red data points: they show that the more carcinogen, the more cancers. But what happens when we extrapolate backward, into the region of very low concentrations typical of natural water? The so-called linear dose-response assumption is that the data would fall along the straight line shown. But is it a good approximation to what happens at those low concentrations? Many scientists believe that the model is not a good one, and there are cases where it is known to be wrong. One could argue that the body has mechanisms for dealing with very low concentrations of carcinogens and that at some low level a carcinogen is not a threat at all. The actual response thus might be more like the curved line shown. This is called the threshold model.

To test the model on a specific case, George S. Bailey and colleagues at Oregon State University studied the effects of extremely low dosages of a known carcinogen, dibenzo[a,l]pyrene on more than 40,000 rainbow trout. With such a large population of fish, small excess cancer levels could be detected. These studies extended the studies of this compound to concentrations a thousand times lower than had been done before. The results showed that the linear dose response method greatly overestimates the cancer risk from this compound at these low concentration levels, by a factor of between 500 and 1,500. In other words, their data are consistent with the threshold model; their data would fall somewhere around the blue line in the graph (however, my drawing is just an approximation, not an accurate representation of the fish study). While this study applies for just this one substance and its effect on one species of fish it is important, because it shows that the linear dose-response model can greatly overestimate the dangers associated with very low concentrations of known carcinogens or other toxic substances. This study thus is significant for those in the EPA responsible for setting exposure limits.

Most people long for certainty in the affairs of their lives. They wish assurance that their jobs are secure for the foreseeable future, that their children are safe at school, that their spouse or significant other is faithful to agreements they have made. Yet we know that many aspects of life are uncertain. We’re unsure of the future of the housing market, of the impacts of climate change, of – well, of an awful lot of things! So we look for pillars of certainty, things that we know are true and will stay true regardless. The foundational documents of governance, such as the Constitution; religious dogma; fundamental scientific laws – all these promise certainty of a kind in particular domains of our concerns. Our reliance on these certainties is often so deep-seated that we instinctively react against evidence that they may not be as immutable as we have been led to believe.

This nearly universal need for certainty poses a continuing challenge for science in its attempts to inform the society outside the scientific community about how the world is. A great many ideas, theories and laws are very widely accepted in science and taken for all practical purposes to be true. Many of these form the basis of the technologies that undergird our modern life. If what science has to say about the operations of lasers were not true, how could they be effective in the multiple uses made of them, from removal of cataracts to reading the contents of CD’s and DVD’s? If very complex theories of combustion and turbulent gas flow were not very reliable descriptions of how airline jet fuel burns and propels a jet aircraft, how likely is it that jet aircraft would ever get off the ground? These examples and thousands of others like it promote the notion that science is a fountain of rigorously true statements and ideas. Yet a great deal that concerns scientists in the course of their everyday work , and that necessarily influences opinions they must deliver on matters consequential to the public good, is clouded by uncertainty. Just how much of a particular carcinogen can we have in our water supply before it constitutes a significant health risk? Scientists can attempt to narrow the range of uncertainty but there is no such thing as a single, true answer.

Scientific witness in the courtroom

This past June the U.S. Supreme court issued a decision with fascinating ramifications for the notion of scientific authority. They ruled that reports from crime laboratories may not be used at trial against a criminal defendant unless the analysts responsible for creating the data are present to give testimony and bear cross-examination. This decision is an interpretation of the Sixth Amendment, which provides in part that an accused has the right “to be confronted with the witnesses against him. “

The case brought before the court arose from the conviction of Luis E. Melendez-Dias on cocaine trafficking charges. Part of the evidence against him was a laboratory report stating that bags of white powder allegedly belonging to Melendez-Dias contained cocaine. The lab report was submitted by prosecutors with an analyst’s certificate, but no analyst appeared to give testimony.

Adam Liptak, reporting in the New York Times on the court decision, notes the unusual way in which the court divided on the 5-to-4 decision. With the majority were Justices Scalia, Thomas, Stevens, Souter and Ginsburg. Dissenting were Justice Kennedy who wrote vigorously for the dissenters; Roberts, Alito and Breyer. This was no ordinary cleavage along conservative/liberal lines! Scalia, writing for the majority, took the view that defendants had the same right to confront adverse expert testimony as they enjoy with respect to any other form of testimony. Kennedy, in dissent, pointed to the huge disruptions that might occur in court cases if every laboratory report needed to be brought to the court by a bona fide representative of the laboratory making the report; that is, a real analyst who could as needed provide expert background testimony. However, according to Jeffrey L. Fisher, a law professor at Stanford, who represented Mr. Melendez-Dias, about a third of states already follow procedures that comply with the new decision.

The court’s decision raises several questions that are of importance for science’s relationship with society. The first level at which to approach this is to ask whether there is a matter here at all of science’s epistemic, or expert, authority. Justice Scalia, in his majority opinion wrote that the Constitution would require allowing defendants to confront witnesses even if “all analysts always possessed the scientific acumen of Mme. Curie and the veracity of Mother Teresa.” In other words, even assuming that the crime lab results are of the highest scientific quality, and that the reporter is a person of impeccable moral standards, the Constitution requires that the defendant have the opportunity to confront the witness. But of course not all crime lab personnel are fully competent, free from making errors of various kinds, or always above suspicion of reporting results tilted toward the prosecution’s case. In these respects, cross examination of a witness reporting forensic results is of a kind with cross examination of any other witness. It really doesn’t go to the question of whether the scientific principles and applied technology that undergird the reported results are sound and relevant to the evidence being presented. Nor does it cover the question of whether the laboratory has obtained the results through full and competent observance of all the required protocols.

There is plenty of reason to be concerned regarding the quality and veracity of much forensic evidence. The National Academies of Science in February of this year issued a report on the state of forensic science in the US, and on what steps might be taken to strengthen it. Quoting from the report’s executive summary, “…in some cases, substantive information and testimony based on faulty forensic science analyses may have contributed to wrongful convictions of innocent people. This fact has demonstrated the potential danger of giving undue weight to evidence and testimony derived from imperfect testing and analysis. Moreover, imprecise or exaggerated expert testimony has sometimes contributed to the admission of erroneous or misleading evidence.” Defense counsel thus may have plenty of grounds for questioning the technical witness that brings forth the forensic evidence. It may be a good strategy to question the basic scientific assumptions underlying the methods employed. On the other hand, when the matter at hand is fairly simple, raising too many questions can be a poor strategy in that it merely serves to call attention to the results. In any event, the defense now possesses a power it had not previously had. Justice Kennedy and the other dissenting justices seem to be very concerned about cases where the analyst may not be available, or where over the passage of time the analyst may have retired, changed jobs and so forth. These are legitimate concerns, but they seem to me to pale in comparison with the prospect of defendants facing a written laboratory report without any means of cross examining the person or persons responsible for the analyses.

It is not always easy to keep the non-scientific world attuned to the notion that the doing of science, even at the level of often mundane analysis of forensic materials, is a human activity. Science is not really about objective truth in some abstract and disembodied sense. It is about kinds of truth found in the course of looking at aspects of the world with a certain kind of eye, with a certain ethic of disinterestedness. That sort of work is done by humans. Even given the best of intentions, errors may be committed, omissions may occur. When scientists report to the larger society on what they have done they should not be perceived as oracles, presenting something drafted by Gods. It is one of science’s shortcomings that is has not engaged the larger society as fully as it should, that science is not seen as the product of human endeavor. Yes, the social structure of science does go a long way toward weeding out errors and falsifications during the formation of new knowledge, but in the day-to-day applications of science, as in a forensic laboratory, human nature is at work. When someone’s future may hang on the outcome of courtroom deliberations, the human who has generated scientific evidence that bears on the case should be there to testify to it.

Competition and war metaphors in science

I have long been interested in the roles of metaphor in science, and find it interesting to note the ways in which metaphors are employed by those actively pursuing scientific research. The subject is of continuing interest, in part because the particular metaphors used as explanatory devices color the nature of the interpretations of observations, and help to shape the directions in which science moves. Several years ago Matthew Chew and Manfred Laubichler published a paper in Science dealing with the sorts of metaphors used in ecological research. They pointed to the pervasive use of war and conflict metaphors in describing ecological dynamics involving introduced species. They criticized the heavy use of metaphors of human conflict because it imparts a strong bias to scientific discussions. To quote from a story on their paper, "In this particular context it is especially interesting that one finds almost no references to 'natural allies' in the literature, yet symbiosis is also a very common ecological phenomenon. Have we become so fixated on war, that we can only perceive nature through that lens?"

I don’t buy fully into Chew and Laubichler’s concerns; there is a certain moralistic tone to them that I think distracts from the larger question of how metaphors are chosen by scientists. Nonetheless, they and others who have written on this theme have a point. There is a general concern in many quarters that the use of war and conflict metaphors engenders still more of the same usage by other workers in that field. This is a question that should yield to empirical analysis, and we should ask whether that is the case. But the prevalence of such metaphors is more a commentary on societal values and preoccupations than the result of idiosyncratic choices by scientists. What we learn from conceptual metaphor theory is that scientists employ conceptual metaphors that are deeply grounded in their basic experiences in the physical and social worlds. If they see much of what occurs in their lives in the domains of politics, government, religion, law or what have you, in terms of conflicts and oppositions, they are bound to employ conceptual frameworks associated with conflicts and oppositions in their attempts to interpret what they see in nature, whether in field studies of ecological systems or microscopic and molecular studies of bacterial colonies and cells. (As an aside, I find it quite mysterious that even today, about 30 years after the appearance of George Lakoff and Mark Johnson’s book on conceptual metaphor theory, and much subsequent work by them and many other workers, there is not a more general appreciation of its explanatory power and consistency.)

Aside from the points I have made above about the pervasive use of competition and war metaphors , there is interesting food for thought regarding the extent to which some of these metaphors are, or could be, taken literally. In his book, “Wetware: A Computer in Every Living Cell”, Dennis Bray outlines the view that single cells are capable of possessing features we ascribe to conscious beings, such as learning, knowledge and awareness. We talk about cells employing “strategies” to avoid toxins, of how cells can “learn” to move along chemical gradients, to “pursue” swimming prey. In using such teleological descriptions of what we see cells do, scientists are mapping their understandings of what they experience in the macro world they live in onto what they “see”, under the microscope if you will. We find these kinds of mappings from one domain to the other quite facile, and they can be fruitful in suggesting new directions for experiments, and for relating one aspect of the science to another. But just because these particular social metaphors are so convenient we must not become so bemused by them that we think that the cells literally “think”, or “learn” or “pursue”. Or should we? Perhaps there is a sense in which we just need to enlarge our definitions of these terms. One way of approaching this topic is to try to imagine other metaphorical frameworks that would serve equally well as explanatory devices for what we observe of cellular behavior.

A recent paper in Science by Laura Johnston is concerned with competitive interactions between cells. It epitomizes the strong thread of competition and conflict that forms the basis of much biological interpretation at the cellular level. She begins as follow: “Competition is pervasive at every level of life – in ecology, economics, between countries and states, and in families – and helps to determine order, status and survival. Competition also occurs at the cellular level, where it plays a role in tissue homeostasis, organ size control, and stem cell maintenance.” So we see here the obvious analogy drawn between processes occurring in the macroscopic social world and those occurring at the cellular level. Figure 2 of her paper has labels such as “Losers die” and “Winners engulf losers”. But when we think about the meanings we normally ascribe to “competition”, or to winning and losing, we can see that these do not have literal meaning at the cellular levels. What we conventionally think of as competition is activity driven by higher order cognitive processes, with motivational underpinnings, emotional content and all the rest. Similarly, winning and losing, even staying alive and dying, are processes that involve complex motivational aspects and complex strategies, as well as raw instinct. What can it possibly mean to a cell to be engulfed by other cells? In employing conceptual metaphors of the kind under discussion, we impose our own cognitive impulses on cellular systems that are simply obeying biochemical demands.
I feel sure one could find ways to think about cell colony growth and development other than in terms of competition and conflict, to take this one example. One could talk in terms of decision theory, about spontaneous allocations of roles, about automata behavior – I’m not equipped to make the biological connections, but I feel sure that there are such ways. The conflict and war metaphors are so commonplace because biological scientists find it easy to draw upon those mappings from daily life, not because of something intrinsic in cellular systems. In turn, those to whom communication is directed can be expected to find them intuitively easy to grasp. Thus, they are an important factor in communication within science and in science’s communications with the larger society. We should, however, be thoughtful about this. As I have described in Imperfect Oracle, the language scientists use has an influence on how nonscientists comprehend what science has to say, and on the spirit in which it is received.

Where in the world was Diego Garcia?

Perhaps I should ask where in the world is Diego Garcia, because at the moment it actually exists - as an atoll in the Pacific ocean about 1,000 miles south of the southern tip of India. It is owned by the United Kingdom; the UK and US jointly operate a large military installation there. The story of how it came to its present ownership and use is interesting, but not what I want to talk about here. Diego Garcia, like many atolls, is not very far above sea level; average elevation on the atoll is about 9 feet. The atoll is one of many concerns of the people at the Pentagon who do long range planning and forecasting, and who need to take into account the likely consequences of global warming.

One of those is a rise in sea level. That the sea level is rising is incontrovertible; but how rapidly and how far? The complexity of the global climate model makes for a lot of uncertainty in this aspect of climate change. What one can say is that processes that produce a rising sea level – for example, loss of the Greenland ice cap - are advancing at rates substantially greater than had been anticipated just a few years ago. Land masses such as Diego Garcia with low elevations are particularly sensitive to a rise in sea level, because weather events and tsunamis push water far up onto the land mass. It is not easy to find shelter on an atoll from even a relatively small tsunami. Maybe in the not too distant future we will ask where Diego Garcia was. So it is no surprise that Pentagon planners are thinking about this little atoll and many other installations, as well as about the social disorders that will surely accompany a rising sea level in poor nations that lie at low elevation, notably Bangladesh. John M. Broder recently reported on this topic in the New York Times. The prospects for future disruptions that will adversely affect national security are evident to many in the Pentagon and to many legislators in congress.

I don’t know whether the comedian Glenn Beck and other denizens of the FoxNews newsroom believe that the sea level is rising, or what the future course of that variable in Earth’s climate may be. They seem not to have any faith in the predictions of the community of climate scientists, as expressed through the Intergovernmental Panel on Climate Change (IPCC), and the scientific reports of hundreds of scientists. They declare themselves unsatisfied with those conclusions, presumably because it follows that global governmental agreements and actions are needed to forestall even greater changes than will likely occur as a result of greenhouse gas emissions that have already occurred. But the natural world doesn’t know about libertarian inclinations; it just is what it is. So denying science's expert authority out of petulance is not a responsible stance.

Meanwhile Andrew C. Revkin reports, also in the New York Times, that the IPCC is being buffeted by a variety of forces that have had the cumulative effect of weakening its moral authority in matters of climate change policy. Charges of bias and cherry-picking studies, an inability of the panel as the highest level voice of the climate change community to report promptly on the fast-changing research understandings related to climate change, the difficulties in rapidly planning and organizing studies and conferences on specific areas of concern as they arise, the pressures from individual nations that grow out of a requirement that sponsoring governments approve the summary document line by line, all make for an unwieldy aggregate. As Revkin notes, the effect has been that “there is scant evidence that nations are acting on its warnings.”

The history of climate change understanding, and of policies that might or might not grow from the vast array of scientific studies already conducted and continuing, provides powerful examples of the distinction between science’s epistemic and moral authority. There is, of course, a coupling between what society thinks it needs from science in the way of knowledge about particular aspects of the natural world and the wherewithal it provides for that knowledge to be obtained. At present, with the exception of a clutch of climate denialists motivated by everything from blinding religious beliefs to libertarian and ultraconservative sensibilities, science’s epistemic authority regarding climate change in progress and the dominating contributions to that change from human activities is widely if not enthusiastically acknowledged. Its moral authority, however; that is, its ability to gain assent to recommendations about what needs to be done to mitigate anthropogenic contributions, is not strong.

Science is not generally very effective in exercising moral authority, for many reasons. One of them is just the difficulty of selling people on making a sacrifice today for a potential gain that is off in the future. But beyond that, science’s place in modern society is not strongly grounded in a cultural acceptance of it as a beneficent, reliable source of knowledge and good advice. I’ve traced the historical and contemporary cultural reasons for this in imperfect Oracle, and point to what science must do to establish a stronger cultural authority in society. There is much work to be done.

Can Jim save the world?

James Hansen is the director of NASA’s Goddard Institute for Space Studies in Manhattan. The research mission of the Institute is to study global climate change. Hansen has been director since 1981. He was among the first climate scientists to call attention to the climatic consequences of increasing CO2 levels in the atmosphere, and he is widely regarded in the climate science community as one of the outstanding figures in the field. He collaborates widely with other scientists.

In the June 29, 2009 issue of The New Yorker magazine Elizabeth Kolbert has written a profile of Hansen in a piece entitled “The Catastrophist”. She recounts how Hansen has over the years become increasingly concerned about the threats to society from global warming. As the models have become more sophisticated, as the data regarding climatic change accumulates, the projected effects of climate changes that will occur if humanity continues on its current trajectory of fossil fuel consumption look progressively more ominous. Kolbert relates how Hansen has over the years become increasingly frustrated with the failure of the political system to act on the basis of scientific evidence for the dangers that lie ahead. Political activism is not Hansen’s métier; he is reportedly rather shy, and does not at all enjoy being in the public eye. Nevertheless, he has become one of the most vocal and insistent voices arguing for immediate and sweeping changes on a global scale. During the years of the Bush administration Hansen was repeatedly pressured to restrict his contacts with public media. Instead of buckling under to these pressures, he went public about the pressures being exerted. Today he is frequently at the battlefronts of the climate wars; speaking to groups of all persuasions and sizes, on radio talk shows, testifying before governmental committees, and participating in demonstrations against construction of new coal-burning power plants. All of this activity has brought him a world of headaches.

James Hansen’s story illustrates vividly the distinction between epistemic and moral authority that I have been at some pains to make in Imperfect Oracle. I can’t imagine that there are any credible climate scientists who would challenge Hansen’s credentials or record of accomplishment, even if they didn’t agree in full with his positions on scientific issues. So he obviously has epistemic authority. But he has gone far outside that range in his vigorous advocacy for large-scale societal responses to the threats posed by fossil fuel emissions and other factors that promote global warming. His 2008 testimony before a congressional committee gives the flavor of his advocacy. His statement is replete with the scientific evidences for impending climate change driven by increasing fossil fuel consumption. That is well and good for “This is the way the world is, and where it is heading” – for epistemic authority. But he then goes on to argue urgently for what must be done if we are to avoid what he envisions as a calamitous future. His frustration with the inaction he sees is evident in statements like this: “CEOs of fossil energy companies know what they are doing and are aware of long-term consequences of continued business as usual. In my opinion, these CEOs should be tried for high crimes against humanity and nature.”

I won’t comment here on the wisdom of using such language in arguing for social change on the basis of scientific evidence. It is the case that Hansen has been vilified in the conservative news and opinion outlets , most of which contest the reality of climate change or disagree with the measures proposed to curb CO2 emissions . For example, in 2007, a NewBusters columnist saw strains of hysteria and mis-information in Hansen’s public pronouncements on climate change going back more than two decades . Look at this piece, and ask yourself, whether or not you are a scientist, just what it conveys about the reliability of Hansen’s predictions. We could dissect this kind of critique to our heart’s content, but it is undeniably true that Hansen has been challenged repeatedly over his forecasts of regional climate change, and changes in the global temperature over the past few decades. Note that these challenges, prompted by Hansen’s highly visible advocacy and sometimes strident opining, deny his epistemic authority. For the fans of those sources, Hansen’s status in the scientific community counts for zilch. Beyond this, however, there is a veritable blizzard of stuff out there questioning his motivations, calling him a liar and a fraud and more - for example.

What can we learn from James Hansen’s story? It is, of course, not over by any means, but if offers an object lesson. Scientists are often at a place where they need to decide whether to advocate, as scientists, for a position or policy in the public realm. Even when scientists are not expert in a given subject area, such as climate science, they are in a position to appreciate much more than non-scientists can the depth of research findings, the extensive accumulations of data over time, the continual back and forth within the scientific community on specific research questions - all that goes into forming a reliable scientific opinion on a complex problem such as global climate change. Scientists who are informed can thus in good conscience promote a serious audience for those scientific findings in the halls of government and in the public sphere. Scientists are also perhaps in a better position than most non-scientists to appreciate the consequences of taking an action or not taking it; for example, reduction of fossil fuel emissions. So they can argue for policies that mitigate emissions of greenhouse gases of all kinds, that promote alternatives to fossil fuels, and that make plans for dealing with the consequences of climate change. In short, scientists can attempt to exercise moral authority in the public sphere. I believe, however, that we will make the most progress by a steady reliance on the science, and on continued efforts to inform non-scientists on what the best scientific opinions is telling us. It is not very useful to get caught up in arguments of the sort that contrarians tend to raise, based on details: the temperatures in the Midwest this past summer, year-to-year changes in the thickness of the Arctic ice sheet, and so on. Rather, it should be focused on explaining how the scientific community comes to the consensus embodied in the IPCC reports, and on the bigger, longer-range course of change. That means that we should individually take a look at those documents as they appear. You can find the latest at IPCC.

In the end, science may prove to have little leverage in shifting societal priorities. There seems to be widespread agreement that the climate is changing, in some places more rapidly than was predicted. But actually making sacrifices to deal now with the seemingly distant threats of climate change will not come easily. The science will eventually out; we will just have to keep on keeping on. At a minimum society will need scientific expertise to help it figure out how to cope with the changes ahead. I know that sounds a bit wimpy; a sort of Kurt Vonnegut response. So be it.

Expert vs. Moral Authority

One of the themes developed in Imperfect Oracle is the distinction between various kinds of authority. Depending on the context, people refer to authority via one or another sobriquet: expert, or epistemic, cultural, moral, coercive, and so on. This sometimes creates confusion about what kinds of authority actually operate in science’s interactions with the larger society. The most important contrast, in my view, is that between expert (epistemic) authority and moral authority. To define the distinction in the most general terms: Epistemic authority as it applies to science is the capacity to make statements of how things are in the world that are taken to be true or a good approximation to the truth. A chemist asserts that a particular arrangement of atoms exists in the molecules of a certain substance; a geologist tells us that a geological formation is composed of a particular set of minerals, and that it was deposited in a particular geological epoch; an oceanographer describes the ways in which increasing concentrations of carbon dioxide are affecting the ocean’s acidity, and the effect this may have on development of shell-bearing organisms. Moral authority, on the other hand, is the capacity to hold forth on how the world should be. All sorts of people claim to possess moral authority, to be able to tell us how we should behave in one respect or another. Moral authority can be based on a variety of sources, among them divine revelation (religious leader), election to a political office (the President), traditional authority (a king or queen), appointive authority (a policeman), or expertise ( a garage mechanic or a scientist).

When scientific findings carry implications for the ways in which things are done or understood in the larger society, there is a potential for conflict with other ways of doing or understanding things. Science then must compete with other societal elements in arguing for acceptance of its findings. In these efforts, whether by individual scientists or by the scientific enterprise more generally, science is arguing for acceptance of science’s epistemic, or expert, authority; that science has the capacity to report reliably on how particular things are in the world, and on how things might change as a result of processes that are occurring. So when thousands of climate scientists all over the world report the results of making measurements and developing models of increasing complexity and capacity to make climate predictions, they are exercising epistemic authority. Out of all that work there has emerged what Michael Polanyi long ago referred to as a ‘scientific opinion’, a product of the way in which the scientific world is organized, of the critical evaluative steps taken in validating individual scientists and particular pieces of scientific work.
With respect to global warming, to cite a salient example, The Intergovernmental Panel on Climate Change has employed processes of sieving, merging, comparing and reconciling scientific reports to produce a consensus. Not every scientist involved in these processes agrees with every element of the final report. Some may find it too conservative in evaluating predictive models, others may feel that a particular component of the entire system has been given too little weight. Because the global climate system is excruciatingly complicated, with many interactive elements, the science is not yet at the point where it can predict climate futures with high precision. Yet the vast bodies of data collected to date are consistent with the best models available, and those models have become increasingly sophisticated as a result of dramatic increases in computational capacity. I have followed this field since the early 1970s, when the earliest computer-based models for predicting global temperature changes due to increasing carbon dioxide levels appeared. I find it remarkable that the predicted increases in global temperature caused by a doubling of the atmospheric CO2 concentration have not really changed a great deal over four decades of intensive scientific development. The scientific research on this topic is an example of science working in society to produce the best possible expert opinion on a matter of grave concern for the world’s human population, advice that is sufficiently reliable to form the basis of actions that society might wish to take in response to the findings.

Entities that are directly or indirectly sources of large CO2 emissions can be expected to look critically at the scientific claims. If they were playing by the same rules as science, their course of action would be to look for scientific evidence that contradicts the accepted findings and predictions. Indeed, there have been debates over whether phenomena such as variable sunspot activity are responsible for global temperature changes. However, the mainstream view of the climate science community has been that explanatory alternatives to greenhouse gas emissions as the major source of global warming do not adequately account for the range of climate changes observed.
Lacking viable scientific explanations for the observed warming effects, the next move for some has been to deny that the planet is warming significantly, or to adopt one or another of a set of positions that refuses to accept scientific authority. Science holds the cards in this contest as it really has no competition as far as expert authority is concerned. The opposition can, however, employ other strategies. One is to weaken the epistemic authority of science by flooding the discussion with counterviews that are supposed to be from legitimate scientists. The public has difficulty in distinguishing one set of credentials from another. For propaganda purposes the weatherman for a radio station in Kansas will do as an “expert” on climate. Thousands of signatures from such "experts" are presented as evidence that the scientific community does not buy into global warming. In another strategy, climate scientists are associated with unpopular views, by invoking terms such as “liberal” or “advocate of big government”. The main point is that a favorite tactic of those who oppose a consensus scientific position, for reasons other than doubts about the science itself, is to undermine the notion that there is indeed a consensus, and concomitantly, that those most vigorously arguing a consensus position are tainted in some way.
So when science attempts to exercise expertise in the world outside science, there is often resistance from other interests.

In my next blog I want to look at what it means for scientists or the science establishment to go beyond expertise , to attempt an exercise of moral authority. For example, science or its representatives would exercise moral authority with respect to the climate change issue by making arguments that go beyond simply the evidence for climate change. They would urge that society should act in some way in light of the prospects for climate change. At this point we come to a new set of questions and concerns. It is not entirely clear that science or individual scientists have any special capacity for exercising moral authority, even on an issue they know a lot about in terms of the underlying causations and likely consequences. Put simply, the capacity to tell it like it is does not in itself convey an authority to pronounce on how it should be. Attempts to exercise moral authority on matters fraught with controversy can be risky. It has been well illustrated in the climate change debates that when scientists offer advice on what, if anything, should be done they sacrifice epistemic authority to some degree, and often let themselves in for a rough time.

Science's Authority

I am back to writing in this blog after a long hiatus, mostly driven by the need to complete some writing projects. In particular, I have been completing review of final pages and preparation of the index for a forthcoming book, Imperfect Oracle: The Epistemic and Moral Authority of Science, which should appear on the bookshelves by mid-September or thereabouts. I have also finished up a shorter work, Bridging Divides: The Origins of the Beckman Institute at Illinois, based on experiences in helping to establish the Beckman Institute at the University of Illinois, Urbana-Champaign. That book should be out by about October 1 at latest.

Now I want to return to blogging, to continuing the theme I began with several months ago: the relationships of science with society, with a special attention to aspects of science’s authority. How does science exercise influence in society? What are the grounds for its claims to having an especially reliable path toward truth with respect to questions that concern the natural world? Why does the public, or various groups of people within the larger society, sometimes accord science a high degree of deference with respect to some issue or question and at other times simply ignore or reject what appears to be an established position within science? Imperfect Oracle is my attempt to deal with these and related matters. The notion of authority can be powerful in shedding light on the day-to-day instances of science’s attempts to exercise influence, and resistances to those attempts that are grounded in commitments to competing social forces: government, law, religion, public culture and so on. Although science has been instrumental in shaping the modern world as no other social force, it is for all that just one among many influences that make up the cultural tenor of modern life. To understand how and to what extent science competes with other social forces, the nature of the authority it exercises, and the limits to that authority, must be understood.

Recent surveys by the Pew Research Center provide a good stepping-off place for this discussion. Pew surveyed two groups of adults. One survey consisted of telephone interviews of the general public, with a sample size of about 2,000 adults. A second survey consisted of a random sample of about 2,500 members of the American Association for the Advancement of Science. The survey of the public was designed to ascertain peoples’ perceptions of both American science and scientists, and attitudes toward both. Here are a few results: The public has high regard for science; 84% think that science has a mostly positive effect on society, and only 6% think it has a mostly negative effect. In rankings of different professions, scientists are thought by 70 % of respondents to contribute “a lot” to society’s well-being. Scientists came in third behind members of the military and teachers, comparably with medical doctors, and well ahead of clergy, journalists, lawyers and business executives. A majority of the public (60%) believes that government funding of research is “essential”. These and many other responses suggest that the public has generally positive feeling about science and scientists.

For their part scientists feel that this is a good time for science (76%), though they have some complaints. Predictably, they don’t feel that there is sufficient funding for basic research (87%). They feel overwhelmingly that the public does not know very much about science (85%), that the news media fail to distinguish between findings that are well-founded and those that are not (76%), and that the public expect solutions to problems too quickly (49%).
These results are pretty much in line with those garnered ten years ago in a similar survey, and results from other surveys conducted over the past couple of decades. The comparison of what scientists believe about the natural world with what members of the general public believe is also consistent with past survey results. As examples, only 32% of the public, as compared with 87% of scientists, believe that humans and other living things have evolved due to natural processes. Only 49% of the public believe that earth is getting warmer because of human activity. Surprisingly, even among those who disagree with the scientific consensus - for example, that living things have evolved – a strong majority affirm that scientists have contributed to the well-being of society.

As we think about these and similar survey results in relation to science’s authority in society, the first important point is that science is generally well-regarded by the public, and scientists are deemed trustworthy. Science’s authority rests upon trust in its expertise, and on the feeling that scientists as a group mean to do the right thing. But that general complaisance does not automatically translate into acceptance of scientific findings when they seem to raise conflicts with beliefs anchored in religion, politics or variously derived social understandings. Furthermore, there is ample evidence based on other surveys, one of which was part of the Pew project, that the public has a quite limited understanding not only of accepted science, but also of how science actually works; that is, the means by which science comes to hold what we can call ‘scientific opinion’. These two factors together combine to weaken science’s influence when there appear to be conflicts between broadly consensual scientific opinion on the one hand, and inured beliefs grounded in experiences and teachings beginning in early life on the other. The multiple influences that determine the extent to which any person is inclined to accept scientific authority seem to operate almost independently of educational attainment or adult life situation. For example, I wrote in this blog in February about George Will’s obdurateness with respect to a scientific matter relating to global warming. From a scientific perspective, Will had virtually no ground (ice?) to stand on in his assertion that arctic ice is not thinning, and that the claim that it is serves as one more example of global warming hysteria. I attempted there to address the question of why an intelligent man with little or no expertise in the subject matter would persist in a assertion that conflicts with a strong scientific consensus. I hope to write in following blogs about similar instances in which individuals or groups adopt positions with respect to scientific questions that amount to direct challenges to scientific authority. The easiest cases to understand are those in which the individual has a financial or powerful political interest that would be adversely impacted by implementing policies based on a scientific consensus; think, for example, Exxon Mobil or Senator James Inhofe. We can call attention to their obvious bias and attempt to counter their views with arguments based on science. It is not so easy to deal with the likes of George Will, religious conservatives, political libertarians, and a host of others who choose to follow the dictates of some other authority or cultural inclination than science in determining their views on a wide range of societally important issues. If we are to make progress in increasing science’s authority, we need to recognize the conflicts with other cultural forces represented in these cases and find ways to present science and scientists more effectively.