(Reading from Appeal to Expert Opinion, by Douglas Walton, p. 19)

Appeal to expert opinion is a complex type of argument because the roles of the two chief parties involved are somewhat at cross-purposes. The user is trying to get some information from the expert. But he, the user, is not himself an expert in the field of the inquiry. Nevertheless, the user has to try to understand what the expert is saying or means to say. The expert is trying her best to impart information or give advice to the user of a kind he will be able to understand, despite his lack of technical knowledge. So the expert is engaging in a kind of scientific or technical reasoning in her field of expertise, and then trying to convey the conclusion of this reasoning (and perhaps explaining how she got it) to the user.

We live in a highly complex and interconnected world with an ever- growing population. Our worldwide civilization is faced with major issues related to supplies of energy, food, and other critical resources. We encounter stories and pictures of very serious environmental degradation that impacts all people worldwide and portents major economic and social dislocation. As citizens of the world and the United States we are faced with making major decisions about highly complex issues involving science, economics, and technology. We are familiar with public discussions concerning science- based issues such as stem cell research, cloning, evolution, climate change, vaccinations and autism, genetically modified organisms, and nuclear power. To this we can add the list of complex economics issues such as the potentially insolvent social security system, the health care crisis, and our deteriorating national infrastructure. I am sure you can expand endlessly on these selections. As citizen of a democratic society we should expect to participate in an informed debate about our national policy options. I worry that we simply are not well enough informed and have a very difficult time discerning when we are hearing from a true expert or simply a paid political hack. All of these issues no matter how they are addressed have the potential of serious economic dislocation as well as dissatisfying faith-based or other values based minorities. These issues are real and they should command our informed engagement. So often the debate in not informed and is clouded by ignorance, dogma or deliberate obfuscation by those with a personal agenda. And this is all complicated by our own individual bias and deeply held and often poorly founded personal opinions. I have come to think about these issues over the past several years mainly because of my personal experiences and observations of the on going public debate concerning Global Climate Change. As I will try to illuminate later in this talk, this particular topic, like so many of the issues facing our society, is one in which "expert opinion" is vital to the publics framing and understanding of the problem and possible solutions. The problem is one that must be investigated and demonstrated by highly specialized experts, in this case a collection of scientific specialties that are broadly covered by the name of climate science, a discipline that has grown up and become recognized in the past 20 to 30 years. The potential solutions to the problem are of a scientific and technological nature but have gigantic implications for the world economy and like all of these issues have serious political implications involving fairness and enforcement. This requires "expert opinion" because of the vast complexity of our highly integrated world economy and the necessity of international treaties and international enforcement mechanisms. One would hope that we could logically separate the issues of quantifying the problem and laying out the solution. So often in public debate the two get intertwined and confused. We have barely formed a consensus on the problem after 20 years of public debate though we seem to be converging and are completely failing in outlining a national program for fixing the problem much less engaged seriously in an international solution. As I will try to demonstrate that when it comes to informed "expert opinion" and how we as a society should deal with that opinion, we should conclude that human caused climate change is on going and as a society we should have been exploring and debating solutions to the problem for the past 10 years and not debating the existence of the problem.

Before I attempt my principal discussion of defining the attributes of "expert opinion" and its philosophical history I would like to dwell for just a moment on some interesting features of human learning and opinion formation that complicate any public discussion of complex issues. There is a significant body of excellent scientific research looking at the natural propensities and limitations of the human mind when it comes to its understanding of the world and how that world functions that should be enlightening of our own limitations in forming opinions. This is important self-knowledge that many of us simply don't incorporate into our understanding of ourselves. In the context of those human limitations it is also important that the general public appreciate the highly structured formal processes that are involved in our worldwide communities of experts and specialists who form bodies of expert opinion by employing structured peer review and criticism. That formal process, while far from perfect, attempts to compensate for individual biases, incompetence and sloppiness. It is appropriately conservative while still open to changing understanding based on new scientific data and resulting insights. And just as democracy should rely on the superiority of our collective intelligence, it actually does so by working hard to identify fraudulence and obfuscation while developing a collective understanding of a given body of expertise. I read an article in the May 18 issue of Science Magazine titled "Childhood Origins of Adult Resistance to Science". The authors claimed that adult resistance to certain scientific ideas could be traced to assumptions and bias that could be experimentally demonstrated in young children and that those things often persisted into adulthood. In particular children and adults resisted scientific information that clashed with common-sense intuition about physical and psychological domains. And I thought, most important, when learning information from other people; both adults and children are sensitive to the trustworthiness of the sources of the information. While this might seem obvious, resistance to science is particularly exaggerated in societies where nonscientific ideologies are somehow grounded in common sense and are transmitted by trustworthy sources. The article pointed out that mind body dualism and creationism were examples of intuitively held beliefs from childhood that directly disagree with a large body of well-established science. These beliefs are particularly likely to be endorsed and transmitted by trusted religious and political authorities. Pew Trust polling data find that 42% of Americans believe that humans and dinosaurs lived together at one time, and even those who accept evolution misunderstand the workings of natural selection. The article reviewed evidence from developmental psychology suggesting that resistance to scientific ideas is really a human universal and derives from what children know and how they learn. The authors discuss childhood predilections toward a flat Earth and purposeful design of the world. We know from the history of knowledge that most adults preferred a flat earth theory to a round earth and that creationist views were the predominant view through most of human history. The authors conclude that people resist scientific findings because they can be unnatural and unintuitive but there is also a very strong cultural component. Simply saying "I believe in evolution" sets a cultural expectation that there are those who don't. While some people might be able to directly evaluate truth in such cases, for most people direct evaluation is impossible. We instead evaluate the source of the information such as our family, our friends, our ministers and our teachers. There is a human predilection to belong and to conform. As a result whole communities of people share common beliefs whether those beliefs are based in fact or not. Specific moral intuitions held by members of a society appear to be a consequence of deference to the views of the community. All of us on some level are aware that this is probably true for ourselves as well.

I have said that expert opinion is critical to our understanding all of the major issues facing human society. What then is an expert and what qualifies as expert opinion? Do we recognize an expert when we see or hear one? How can we meaningfully engage with expert opinion? We have all probably seen and heard expert scientists, economists, historians and many other subject area experts in our college classrooms and in various media outlets such as NPR and PBS. The news programs often give us clips of experts testifying before Congressional committees. Very often the news media trot out two experts each with a different take on the same technical issues providing us with a "so called" balanced presentation of expert opinion. During the period of the "Tobacco Wars" the television networks presented experts explaining nicotine addiction and the potential health risks of smoking and balanced that with Tobacco Company "scientists" explaining the tentative and questionable nature of the medical research. The media outlets have subjected us to the same "balanced" views relative to the Global Climate debates of the past 20 years. We have all read stories about major litigation in which both sides trot out an expert. This has given expert opinion a very bad reputation with the public. Now there certainly are cases where we hear little or no conflict from experts in the media but that usually has to do with purely scientific findings and doesn't involve somebody's pocketbook. We understand that when major economic interests fear the consequences of informed public debate they will engage with all manner of obfuscation including creating or finding a number of contrarians in the expert community. No collection of human beings is ever completely monolithic in their opinions on potentially controversial issues. I have emphasized the inherent conservative nature of a working community of experts. Ideas that are contradictory of the accepted body of opinion may take years to win acceptance particularly if they are subtle or involve out of the ordinary interpretations of existing data. It is what we want from an expert community. They should be open to a new interpretation or a new body of evidence but they certainly should not be jumping on the bandwagon with every new concept that comes along. In science we should never believe that the body of accepted truth would not change as a result of new discoveries and insights. There are many examples of new and revolutionary ideas that took many years to win general acceptance within their communities of expertise. Einstein's photon theory of light that appeared in 1905 was not fully accepted by the physics community for twenty years.

A little over a week ago I was directed to book by a Canadian Academic philosopher, Douglas Walton, published by the Pennsylvania State University Press. The book is titled "Appeal to Expert Opinion". It is a philosophical treatise on the history and development of expert opinion from the early Greeks to modern times. I have attempted to work my way through the book as I was writing this sermon. I have managed to incorporate many ideas from the book. I don't recommend the book unless you are interested in slogging through a dense history of expert opinion that seemed to me somewhat irrelevant to the modern issue. But I am a scientist and not a philosopher logician who dots every i and crosses every t with precise care. It was fascinating to me to discover that the issue of expert opinion goes all the way back to the 5th century BC and was dealt with by Plato and Aristotle as well as many medieval philosophers and theologians. Walton credits John Locke with being the father of modern philosophical discussions of expert opinion and by modern I mean in the sense of Modernism, the philosophical movement associated with the Enlightenment. He treats fairly fully with the problems that Post-Modernism has with expert opinion as a source of homogenize truth, much of which I personally take great exception too. Walton claims that expert opinion is a form of what philosophers would call "argument from authority" that has a very mixed record in terms of its contribution to human enlightenment. In fact many of the theologians and some important philosophers of the middle ages used "argument from authority" as the basic foundation for church absolutism sighting human ignorance and foolishness as warranting the intercession of God's authority through the church into human affairs. Expert opinion on the other hand assumes the listener has a mind capable of entertaining complex ideas and discerning some truth within that opinion. It is an argument from authority that expects a critical listener. Walton does eventually get around to pointing out that expert opinion in its manifestation in modern times is a form of dialectic (that is discussion) rather than a pure authoritarian pronouncement and makes little sense if the hearer can not in some way engage with the expert to fathom the process and basis of the experts arriving at an opinion.

I believe the most important conclusions of Walton's book are examined in Chapter 7, which is titled "critical questions". In this chapter Walton presents a thorough survey of the modern literature on philosophical opinion of how experts and expert opinion should be judged. Through ten sections he performs a close look at the collection of questions that must be posed in the judgment process. I will attempt a simplistic summary of his conclusions in which he attempts to include all the important aspects of the predominance of philosophical opinion in this arena. The questions seem very obvious once you hear them and unless you read the book you might wonder how it took 30 pages to explain them.

1. Is the judgment (the expert opinion) by the authority within their field of expertise? (Is she speaking about something that she is truly qualified to speak about as an expert?)
2. Is the authority truly a recognized expert or just a celebrity? (Think about advertising or talk shows)
3. Even if the individual is an expert in the field is the argument really plausible? Which really means did she explain herself well enough that you can believe what she has said.
4. Is there general agreement on the argument within the field of expertise? If there is disagreement, how serious and prevalent is it? Did the expert give you all sides of the story or explain why there is only one side to the story.)
5. Is there a body of objective evidence on the cited opinion still available and is the opinion still current within that body of evidence? (In another words has the expert community changed its mind and can she site the objective evidence that leads her to her opinion.)
6. If the expert is being quoted rather than speaking herself is the expert's say-so been correctly interpreted?

Walton adds a series of sub-questions under each of these questions but I think this list captures the essence of the arguments. I should point out that it was at this point that I discovered that the book seems principally aimed at helping judges and lawyers in the specific case of expert witness in trial settings but all of the arguments are applicable to the wider issues of expert opinion.

This is really a very straight forward set of questions that in this day and age can be easily verified by most people relative to the testimony of most experts. We would like the media to ask just this set of question of any so-called expert that they parade before the public. Most experts maintain web pages with the their personal biographies on them. Their publications and their standing within their professional community can be readily obtained. The web is full of information concerning most important testimony before Congress and most expert opinion relative to important national and transnational issues.

Let us apply this set of questions to the case of Global Climate Change. If Al Gore was our only source of information we would probably have to say he does not meet the criteria established by this set of questions principally because he is a celebrity, not an expert and he did not directly identify the true sources of the expert opinions he presented in his movie. On the other hand the primary source of expert opinion that has been presented to the world is from the members of the Intergovernmental Panel on Climate Change who wrote the United Nations report. They are all recognized experts in the field. The judgments within the report are well within their area of accepted expertise. There arguments are highly plausible. There is a wide consensus (almost unanimous) within the field of climate science. The body of objective evidence is still current and actually growing daily. The IPCC report has been written and rewritten and is the direct report of these experts. By Walton's criteria for judging credibility great credence should be given to the problem of Climate Change due to human activity and the probability that serious consequence will result for mankind if nothing is done to ameliorate the injection of CO2 into the atmosphere. As I have pointed out with the "Tobacco Wars" there is a small- dedicated core of scientific contrarians who are principally funded by the oil and coal industry who continue to fill the airwaves and Internet with scientific obfuscation and in some cases ad homenum arguments attacking the integrity of an entire community of dedicated scientists. There is even now a contrarian novel, "State of Fear" by Michael Crichton questioning the intellectual integrity of the entire worldwide community of climate science that is rife with technical errors.

As for our total collection of complex socioeconomic problems we need to hear the arguments of the experts so that we may begin to form a society wide consensus on how to proceed to solutions rather than arguing about whether the problems are real or not. As someone who is expecting to receive social security in three years I am very concerned that we are not having a wider discussion on its long-term viability.

It is very interesting to me to realize that most everything we believe we know is based on the opinion of some expert or someone's interpretation of expert opinion. Most information comes to us indirectly through people, through written material and through the media. We live in a highly complex society were each of us is really quite specialized in what we do so our span of real expertise is by necessity quite limited. As time has progressed particularly over the past 200 years the nature of society has forced most people to become more and more specialized. We live in a social setting that surrounds us with so many things that are critical to our functioning that we only understand through someone else's expertise. We simply cannot function without accepting the opinions of some authority. If your car is making funny noises you talk to an auto mechanic. When your tooth aches you visit your dentist. We depend on doctors, lawyers, accountants, investment advisors, plumbers, painters, carpenters, historians, airline pilots, air traffic controllers and a myriad of other experts whose authoritative opinions and actions encompass a vast swath of our lives. We know what is happening at the four corners of the world because newspapers, television, radio, the internet and more all bring information to us from someone else's immediate experience and interpretation. We depend on that information not being overly filtered and manipulated and we should be trying to test its validity any way available to us. We have developed some level of skill in sorting what our doctors, lawyers, and auto mechanics tell us with more or less success, We must remain vigilant to misinformation and propaganda of which there is way to much masquerading as real information and news. A much more difficult task is seeing through our own prejudices and dogmatism and how they color our perception of reality. If we want a realistic understand of the world we must work very hard to detect the distortions in what is coming at us and to prevent the distortions we would introduce ourselves.

[Delivered 19 August 2007. David Simons is a member of the Unitarian Universalist Fellowship of Stanislaus County. He earned his Ph.D. in physics from the University of Maryland in 1974. His doctoral thesis concerned the energization mechanisms of electrons in the Aurora Borealis. He led the atmospheric sciences group at Los Alamos National Laboratory in the 1980's, working on a diverse set of physics and chemistry problems related to nuclear explosions, radio propagation, radiations transport, lightning physics, near earth space plasma dynamics and complex terrain atmospheric circulation. He has worked at the Lawrence Livermore National Laboratory since 2001.]