Does consensus serve as a sufficient legitimation of knowledge?
This question pertains to today’s debates because debaters sometimes posit consensus as a criterion for truth or even as a reason to end the debate. Sometimes these debates surround questions where scientists, historians, or other experts conclude disproportionately on one side of the debate (or appear to do so). Debates over global warming, consequences of vaccinations, and Shakespearian authorship come to mind.[i]
Of course consensus does not equal truth: one cannot logically conclude from a general or even a universal agreement about a proposition that the said proposition is true or false. What everybody knows may be dead wrong, and as Joseph Sobran notes, “often what ‘everybody knows’ today is directly opposite to what ‘everybody knew’ a generation earlier.”[ii] Sobran observes that we often repeat what everybody knows without really knowing what we are repeating. We repeat without understanding. We repeat without having a real basis for repeating other than the fact (or fiction) of consensus.
Consensus as a criterion for legitimation or validation has become more suspect in the postmodern age. Postmodernists such as Jean-François Lyotard depict the scientist as operating within imaginative linguistic narratives. Like everyone else, the scientist is a teller of stories, but one “duty bound to verify them.”[iii] Like every other storyteller in the postmodern age, the scientist does not have recourse to the grand narratives, but only to the little narratives that allow room for paralogy, dissent, undecidables, catastrophes, conflicts of interpretation, unknowability, and disagreement about the meaning and method of science.
For Lyotard, consensus is “only a particular state of discussion, not its end.”[iv] In making consensus the end of discussion, we risk making consensus – the communal story – into a grand narrative, a narrative that violently totalizes, that offers no hospitality to other narratives and no room for paralogy or difference. Positing consensus as a reason to end the debate closes us off to the generation of new ideas and what might actually be the truth.[v]
When consensus is popularized, the fact of consensus supplants knowledge of what the consensus concerns: the agreed upon conclusions join the endlessly repeated and little understood body of what everybody knows.
[i] Consensus also plays a legitimizing role in the processes of democracy and trial by jury. Democracies imply a trust in the democratic process: justice will be reached through the political process of deliberation and discussion. Our legal system presupposes a basic faith that consensus among the jurors will correspond to the guilt or innocence of the accused.
[iii] The Postmodern Condition, 60
[iv] 65
[v] Politicians eager to enact their policies may look to consensus as reason to move forward in the enactment, and while political policies need not have certain knowledge as their basis to be prudent policies, the politicians and the public should maintain a healthy skepticism of the consensus or, at the very least, an openness to alternative conclusions that may call into the question the prudence of a political policy.
Posted by Kyle R. Cupp 
