Inferring and Explaining

101 over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations. 10 Notice the challenge she faces. She is making a claim about a very large, and not that well- defned, population—science (“great scientifc uncertainty”). To make matters worse, policy makers and the media dispute her claim. Her frst move is to more carefully defne the population she is interested in. She utilizes a standard reference tool in the natural sciences, the Institute for Scientifc Information (ISI) data- base. In this database, authors are asked to iden- tify certain “key words,” really topics, that their articles address. Professor Oreskes searched for the key word “climate change.” Her team then randomly selected more than 928 articles. Obviously not every article is going to explic- itly endorse or disagree with the consensus view, soOreskes andher teamhad to readand “code” the articles.Teybroke themdown into sixcategories. Te 928 papers were divided into six categories: explicit endorsement of the consensus position, evaluation of impacts, mitigation proposals, methods, paleoclimate analysis, and rejection of the consensus position. Of all the papers, 75% fell into the frst three categories, either explicitly or implicitly accepting the consensus view; 25% dealt with methods or paleoclimate, taking no position on current anthropogenic climate change. Remarkably, noneof thepapersdisagreedwiththeconsensus position. 11 She is also quite candid that a certain amount of judgment and editing of the samplewas required. Some abstracts were deleted fromour analysis because, although the authors had put “climate change” in their key words, the paper was not about climate change. 12 So what do we (none of us trained climate sci- entists) think of Professor Oreskes’s evidence? We possess the tools to make some sort of evaluation. We have a fair amount of data that is being ofered as evidence: statIstICs e 1 . Defnition of the “consensus view” e 2 . ISI database e 3 . Key word: climate change e 4 . 928 articles e 5 . Some articles did not really address cli- mate change and were removed. e 6 . Six potential categories e 7 . 75 percent “implicitly or explicitly” endorsed the consensus view. e 8 . 25 percent took no stand. e 9 . Not one article disagreed with the con- sensus view. t 0 . Almost all scientists working and publish- ing on climate change endorse the consen- sus view. Rival Explanations of the Sample We will begin with two diferent rival explana- tions that attribute the fact that no one chal- lenged the consensus view to pure chance. Perhaps it was just a fuke that all 928 articles either endorsed the consensus view or took no position on it. Perhaps the study tells us some- thing about the articles in the ISI database, but it’s simply a fuke that the articles that the data- base includes are not skeptical but that other peer-reviewed articles not included are skepti- cal. Either of the following sorts of mathemati- cal coincidence is possible: