Should Scientific Truth Be Subjected to a Vote?
With public controversies over issues from vaccinations and disease outbreaks, to climate change and genetically modified foods, politicians and journalists on all sides have lately grown fond of citing scientific “consensus.” They do so with a view to buttressing some policy prescription or other. The idea is that scientific consensus, like aces, always trumps. If “scientists all agree,” then one had better not disagree.
But the view that scientific truth is a matter of consensus, expedient though it may be – for politicians and pundits no less than scientists themselves – is misleading at best. Appeals to “consensus” often reflect a simplistic picture of scientific inquiry that purports to end the need for critical reflection, much less debate, on the part of non-scientists.
Those who promulgate the rhetoric of consensus rightly want to preserve the integrity of science in the eyes of the public. The empirical, precise, and collaborative method of natural science remains – despite the current reproducibility crisis – our most reliable source for knowledge about the natural world. And it often facilitates tremendous technological achievement. No surprise that its practitioners enjoy a high degree of what sociologist Pierre Bourdieu called “cultural capital.” They ought to.
Of course, there is broader agreement – "consensus" – among natural scientists about the fundamentals of their subfields than there is among literary critics, philosophers, or even social scientists. Economists, for their part, can’t even agree on how to measure income inequality; philosophers can’t agree on what philosophy is.
Those who appeal to “consensus” are also right in the claim that non-scientists should be careful when criticizing scientific findings. These latter presuppose complex methods of testing and analysis, which require years of education and practice few have the capacity, time, or interest to acquire. One should no more ask a priest or politician for the latest in nuclear physics than a nuclear physicist for guidance on things spiritual or political.
But none of this means that the lay public must accept uncritically every scientific finding for which there is a purported consensus, much less the alleged policy implications. "Consensus" may be the privilege of science, but critical thinking is a common good and should be open to and practiced by all.
Those who appeal to consensus in order to shut out dissent enjoy the psychological comfort that the illusion of certainty provides along with the political expediency of discrediting one’s opponents by fiat. In doing so, they stand at the threshold of an ancient sophism, which holds that truth is whatever man fashions it to be – or what the experts fashion it to be.
Several millennia ago, Plato criticized Protagoras – a leading “sophist,” or expert on philosophy, rhetoric, and statecraft – for defending such a view. For Plato, truth is not what we are told or what the majority believes but rather something we discover for ourselves through philosophical inquiry.
Aristotle, who was not as skeptical of expertise as his teacher, sought a middle way. Universal agreement may not be sufficient for truth, but it is good reason to take the matter seriously. Thus Aristotle often begins his treatises by setting out the received view – what the “consensus” is – for a given topic. Even if the consensus is wrong, Aristotle thought, it likely contains a kernel of truth and hence must be subject to critical analysis.
Our public discourse about science swings from Protagoras to Plato and back; we suffer for want of Aristotle’s sagacity.
Leave to one side this ancient philosophical dispute, about which there remains no philosophical consensus. The real problem is that consensus rhetoric obscures the nature of modern scientific inquiry and indeed human sociology.
Scientists, it should go without saying, are, like all people, fallible and subject to selfish and ideological biases. Any textbook on the history of twentieth century science will quiet any doubts on that score. A frightening number of disturbing policy prescriptions, from compulsory sterilization to racial war, at one time boasted a scientific "consensus" as justification.
What’s more, scientists, like all people, can be flat out ignorant about issues that exceed their expertise. The average scientist is a dilettante like any other citizen when it comes to topics outside of science – or even outside his or her immediate research area. Modern natural scientists are, increasingly, hyper-specialists, not generalists.
Try asking a geneticist to explain the various subtleties of quantum field theory; or a particle physicist to update you on the latest in germline engineering. Of course, such specialists might be knowledgeable beyond their subfield – and very likely possess the requisite skills to become so. But so too might any well-educated and curious citizen. The point, obvious though often forgotten, is that there is nothing about scientific expertise in one area that guarantees expertise, eloquence, or brilliance in others.
As the celebrated scientist and philosopher Thomas Kuhn pointed out long ago, scientists are inculcated into particular subfields that require their own specialized knowledge and skills, nested within a vast array of other such subfields, and typically do not interact. Scientists are not all equally skilled and objective practitioners of a single research field.
To be sure, the subfields of natural science take for granted a range of fundamental hypotheses and assumptions, for example about what constitutes proper methodology or standards of evidence. But that does not amount to truth by consensus. Rather, it is a feature of the collaborative and piecemeal approach to problem solving that makes natural science unique. Scientific inquiry may be collaborative, but that does not mean that scientific truth can be obtained by polling scientists about the issue du jour and cherry-picking whatever outcome receives the most votes.
Moreover, as history shows, even the most basic suppositions of natural science – from the indivisibility of atoms to classical determinism – are not immune to revision on the basis of experiment. Consensus, for what it’s worth, is a moving target. That presents a challenge for policymakers. And yet scientists too should be wary of hitching their cart to the vagaries of partisan politics; for here too everything is subject to revision, not on the basis of experiment, but rather political opportunism. Politicians are subject to vote. Scientific truth is not.
At its core, scientific truth is not democratic; or rather, it is like a representative, not a direct, democracy. It depends upon a class of rational agents that the public has invested with a certain power, in this case, to inquire into the essence of the natural world. But the public has the right or obligation to remain critically engaged with that undertaking, lest democracy become demagoguery.