Scientific Consensus

The phrase “Scientists agree that …” is ubiquitous in the popular press. Such statements are employed to sell pharmaceuticals, inspire conservation efforts, and alert the public about health emergencies. Only rarely are these politically or economically motivated statements entirely true, and even when scientists do agree, the assertion that “scientists agree” masks the considerable effort made to achieve agreement.

Still, scientists are motivated to achieve consensus. The concise definition, the identifiable single causal agent, and the elegant proof are the anticipated ends to frenzied, even messy searches or years of deliberate and tedious investigation. The excited conversation, the multiple theories, and the competition are expected to eventually subside, leaving the simple factlike statement—X is the cause of Y, or X is Y—distributed in textbooks and protected from unraveling by that hard coating of grammar. This grammar is ideally reserved for only those conclusions that have gone through the rituals of community agreement and demonstration. Or, at least, the community expects factlike statements to be what they seem to be—indications that the frenzied or tedious search has come to an end and a consensus has been achieved.

Yet just as agreement is the goal, disagreement is the catalyst of scientific progress. While every scientific discipline contains a set of core observations, procedures, and theories generally agreed to be accurate, useful, and true—the textbook knowledge of the discipline—no discipline would progress without disagreement. All good scientists hope to identify an unsolved problem, an undiscovered agent, a new disease, a new method that will disrupt and challenge consensus. And all good communication scholars examining agreement in science hope to identify the ways scientists convince each other that their challenge to the consensus, from the modest alteration to the heretical, is credible.