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| Thomas Kuhn |
As Thomas Kuhn pointed out, from time to time there are shifts in the scientific paradigm that cause sharp deviations in the direction of research. These shifts can occur in any of the sciences. Here are some important historical examples:
Puerperal fever was for centuries the leading cause of death in women giving birth. In 1795, the Scottish obstetrician Alexander Gordon claimed that the disease was transmitted by doctors and midwives. In 1842, the English physician Thomas Watson, known for his description of the aortic pulse, recommended that doctors wash their hands with diluted lye before attending a birth. And in 1847, the Austrian physician Ignaz Semmelweis advised the same, based on data showing that the incidence of puerperal fever was higher in hospitals than in births taking place at home, and higher among women in labor attended by doctors than by midwives. Semmelweis' proposals were violently rejected by contemporary physicians, who were outraged by the idea of being blamed for infections caused by themselves, to the point that Semmelweis was committed to an asylum where he only survived two weeks. His death is believed to have been the result of a beating by the asylum guards when Semmelweis, who was 47 years old, tried to escape. His proposals were confirmed by the discovery of the germ theory of infectious diseases by Louis Pasteur, according to which diseases are caused by microorganisms, and not by miasmas transmitted by air, as previously believed. This caused an abrupt change in the scientific paradigm applied to medicine.
In 1854, in connection with the same paradigm shift
and on the occasion of a cholera epidemic in
London, the English doctor John Snow discovered that the disease
caused more victims in areas where drinking water was contaminated by feces.
Faced with the rejection of his idea, Snow made the drastic decision to remove
the lever from the water pump at a well in Broad Street, Soho, forcing the
inhabitants of the neighborhood to look for water in other wells. His action
put an end to the epidemic, although Snow was unable to explain the reason,
because when he died, Louis Pasteur was still a few years away from formulating
the germ theory of infectious diseases. One year earlier, Snow, who was Queen
Victoria's personal physician, had helped her during her eighth and ninth labors
and was a pioneer in the use of chloroform to achieve painless labors, which
made him famous, although the use of anesthetics was not well regarded by many
doctors, or by the Church of England.
At the end of the 19th century, it was often said that
physics had discovered everything that could be discovered. Only two small
phenomena remained to be explained: the negative result of the
Michelson-Morley experiment and blackbody radiation. Once
this was achieved, theorical physics would be closed. But between 1890 and
1927, the discovery of radioactivity, quantum theory and the theory of
relativity revolutionized this science and opened up vast fields of research,
changing the scientific paradigm so drastically that from then on, standard
physics is defined by the two theories mentioned above.
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| Niels Bohr |
The new paradigm was not easy to accept. One of its
creators, Albert Einstein, always refused to accept Niels Bohr's quantum
theory, even though he himself was one of its precursors, and even received the
Nobel Prize for his quantum explanation of the photoelectric effect.
A century later, the controversy continues, as I explained in a
recent post.
Even now, a century after Bohr formulated his theory,
many physicists prefer to cling to the many-worlds interpretation of Hugh
Everett III, which I consider to be one of the most absurd theories ever
concocted by physicists. They will say that I am resisting their paradigm
shift, but I claim that they are resisting the previous paradigm shift caused
by the Copenhagen interpretation of quantum theory.
For most of the 20th century, doctors insisted that stomach and duodenal ulcers were caused by
stress and excess acid in the stomach. During the 1980s, Australian doctors
Barry Marshall and John Warren demonstrated that ulcers are caused by infection
by the bacteria Helicobacter pylori, making it possible to cure
them with antibiotics. Many doctors opposed the idea, as did some
pharmaceutical companies that made huge profits from the sale of antacids, but
the new paradigm eventually prevailed and the two discoverers were awarded the
Nobel Prize in Physiology or Medicine in 2005.
Here are three quotes on these issues, taken from the
book Radical
Uncertainty: Decision Making Beyond the Numbers by Mervyn King and John
Kay. One is by a famous physicist, another by a business manager, and the third
by the authors of the book:
A new scientific truth does not triumph
by convincing its opponents and making them see the light, but rather because
its opponents eventually die, and a new generation grows up that is familiar
with it. (Max Planck, Scientific
Autobiography and Other Papers, 1968).
Gentlemen, I take it we are all in
complete agreement on the decision here. Then, I propose we postpone further
discussion of this matter until the next meeting to give ourselves time to
develop disagreement, and perhaps gain some understanding of what the decision
is all about. (Alfred Sloan, General Motors CEO, 1923-1946).
The willingness to challenge a narrative is a key element not only in scientific progress but to good decision making. (King & Kay, chapter 16).
Thematic Thread about Science in General: Previous Next
Manuel Alfonseca
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