A 21st-century enlightenment

The fact that an opinion has been widely held is no evidence whatever that it is not utterly absurd; indeed, in view of the silliness of the majority of mankind, a widespread belief is more likely to be foolish than sensible. - Bertrand Russell

A story about Albert Einstein dates to his time at Princeton. It seems the great physicist had fallen into the habit of posing the same examination questions every year. Confronted by the Dean for his apparent laziness, Einstein explained that his questions were the same-but the answers kept changing. This story is doubtless apocryphal, yet it makes a vital point; science is always unfinished business. As they used to say on the old X-Files TV show, "The truth is out there," but we never quite get to it. Our knowledge is always provisional. The best we can hope to achieve from the advance of science is a closer and closer approximation to the truth.

Curiosity, independence of judgement, and scepticism are the drivers of scientific progress. Of the three, scepticism is the most powerful. As sociologist Robert Merton noted, "Most institutions demand unqualified faith; but … science makes scepticism a virtue." Questioning prevailing beliefs is the way scientists progressively deepen their understanding.

Scientific scepticism is different from mere disbelief. Any idea can be rejected no matter how much evidence exists to the contrary. Donald Trump claimed that exercise is bad for you and that asbestos "got a bad rap." Former South African President, Thabo Mbeki, rejected any connection between AIDS and HIV, which he considered a harmless virus. US Presidential candidate, Mike Huckabee, described evolution as "just another theory." Robert Kennedy Jr. believes that vaccines (not just the anti-covid variety) cause more harm than good. These opinions are not examples of scientific thinking. At best, they are a form of dogmatism, a stubborn clinging to a point-of-view while rejecting the vast preponderance of the evidence. At worst, the critics of science adopt an attitude of postmodern nihilism. Objective reality is an illusion, so the evidence is irrelevant, and one view is as good as another. Scientific inquiry is different. It employs a particular type of scepticism called constructive dissent.

Constructive dissent

In 1968, Lord (Eric) Ashby, Vice-Chancellor of Cambridge University, delivered an address to the Association of Commonwealth Universities in Sydney. In his speech, Ashby suggested that academics take an "oath" like the Hippocratic Oath once taken by doctors. This academic oath would describe researchers' values and ethics, including "the discipline of constructive dissent."

According to Ashby, constructive dissent "must shift the state of opinion about a subject in such a way that the experts concur." It is not enough to reject a connection between HIV and AIDS, condemn all vaccines or reject evolution. To make a valuable contribution to knowledge, dissenters must use their expertise and observations to convince experts in their field to change their views. Critics who have no expertise, make no observations, and do not even try to persuade experts, are pseudo-sceptics who carefully select bits of evidence to defend their preconceived positions.

The road toward scientific truth is neither straight nor smooth. Few scientists are capable of what the mathematician Henri Poincaré called "flawless reasoning." There are always unexpected twists and turns, which is why the answers to Einstein's questions keep changing. Still, history records many examples of how constructive dissent advances our understanding: Copernicus, Galileo, Pasteur, the list of scholars who struggled against various dogmas is long and glorious. One particularly moving story concerns a Hungarian doctor named Ignaz Semmelweis.

Disinfecting hands

Ignaz Semmelweis was an early 19th century obstetrician. His career was devoted to the care of mothers and babies. In Vienna, where he worked, he was troubled to find that one mother in 10 died of "childbed fever." Today, we know bacterial infections caused these deaths, but no one had heard of bacteria in Semmelweis' time. Pasteur's pioneering work was still decades in the future.

Semmelweis was a careful observer of hospital routines. He noticed that doctors often went directly from dissecting corpses in the morgue to examining mothers and delivering babies in the maternity ward. He wondered whether doctors were transferring disease from the cadavers to the mothers. Semmelweis asked the other doctors to wash their hands with a chlorine solution before touching the mothers to test this hypothesis.

Semmelweis' colleagues were not impressed. How could a nobody, not even Austrian, dare to suggest that his experienced colleagues are killing their patients? Anyway, most doctors washed their hands with soap and water when they left the dissecting room. Their hands looked clean when they entered the maternity ward. If there were something too small to see on their hands, it would surely be too small to cause the death of a mother during childbirth.