Any
discussion on the History and Philosophy of Science necessarily involves the
work of Thomas Samuel Kuhn (1922-1996), who authored, among other works, the
book "The Structure of Scientific Revolutions."
In this book, Kuhn explains that
scientific practice alternates between periods of "normal science" –
based on a paradigm – and periods of "scientific revolution," when a
paradigm shift occurs. Let's discuss the meaning of these terms.
Normal Science means conducting research based on established scientific
achievements recognized by a specific community of scientists. Since scientists
are committed to the same way of doing science, they share knowledge and ways
of thinking. Thus, researchers learn how to solve problems through courses,
laboratories, books, and manuals.
Puzzles and Exemplars
The search for solutions to problems, which Kuhn called "puzzles," is
carried out using techniques learned from exemplars. These are the theories that
dictate research methods and provide guidelines for scientific work.
Paradigm
Scientific research is guided not only by theories but by something broader:
the paradigm.
But what is a paradigm?
It is a set of practices that defines
the behavior of scientists during a specific period.
In a given scientific field, you have a
paradigm when you know:
· The established truths.
·
What can be observed and examined.
·
What kinds of questions can be asked and
researched to obtain answers on the subject.
·
How these questions should be
structured.
·
How the results of scientific research
should be interpreted.
Kuhn conceptualized paradigm in 1970 as:
“a
complete set of beliefs, values, techniques, and everything else that is shared
by the members of a given community.”
Later, Kuhn explained that:
“paradigms
[are] actual solutions to puzzles that, used as models or examples, can be
treated as if they were explicit rules and serve as the basis for solving the
remaining puzzles of normal science.”
However, the word "paradigm"
took on a life of its own. In fact, Kuhn acknowledged that the concept escaped
his initial intentions.
In the Brazilian Portuguese translation, the concept of paradigm is
inadequately expressed. It states: “paradigms are universally recognized
scientific realizations that, for a time, provide model problems and solutions
for a community of practitioners of a science.”
Paradigm Shift
Changing a paradigm is not easy. It means "acquiring" new values (an
effort) and erasing old ones (a greater effort).
Changing a paradigm is not about
changing techniques, texts, or equipment, as some think – but rather acquiring
a "new
worldview," which can be shared by an entire
community of scientists.
Ultimately, a paradigm's success depends
on the space it creates for new discoveries. If a scientific achievement can
solve puzzles that previously had no satisfactory solution and is sufficiently
original to attract a group of good scientists to the point of making them
abandon the paradigm they knew, then you are facing a "revolution."
Scientific Revolution occurs when a paradigm shift happens. Following this change,
science evolves normally for some time within the new paradigm. But the force
of a paradigm is powerful.
Most of the time, science exhibits
adherence to the paradigm. The puzzles proposed for scientists to solve are
confined within it. This would explain why scientific revolutions are rare.
Anomalous Cases
Science enters a crisis when confidence is lost in the paradigm's ability to
resolve discrepant cases – the so-called "anomalous cases." This then
paves the way for a scientific revolution and the construction of a new
paradigm.
An Example of a Paradigm Shift
When Christian Barnard replaced one
man's heart with another's, he showed the world that a person could live with
another's heart. He displayed not just a result – but shattered a paradigm
("one must die when the heart dies") and, in its place, another emerged:
"organs can be transplanted."
When a new paradigm emerges, the
structure of the entire scientific community is affected. The acceptance of a
new paradigm – at least for a time – is not due solely to logical resources or
evidence, experimental or otherwise. The truth is that scientists adhering to
different paradigms have different views of the same phenomenon (while one sees
the Sun revolving around the Earth, the other sees the Earth revolving around
the Sun).
Sometimes, it becomes impossible to
justify a scientist's or a group of scientists' preference for a particular
paradigm. Those defending the new paradigm can campaign and seek new adherents
through conversion or simply wait for the most resistant to die out. But there
will always be a period of accommodation. On the other hand, some recognize a
change immediately.
A Recognition of Paradigm Shift
The dentist Horace Wells (1815-1848) was
undoubtedly the first to use anesthesia in surgical procedures. At the time,
the importance of his proposal was not recognized. But, to demonstrate the
anesthetic effect of sulfuric ether, a Harvard Medical student asked the
Professor of Surgery to anesthetize a patient scheduled for a leg amputation at
Massachusetts General Hospital. This was done in 1846. The patient showed no
signs of pain during the operation, and Professor John Warren Collins
(1778-1856) was moved to tears. He immediately recognized the change in the
course of surgical history.
But when this happens – a paradigm shift
– many things also change: how a scientist sees the world; the criteria for
selecting important problems; research techniques; how phenomena are
interpreted; the criteria for evaluating theories.
Scientific activity is critical. Being
critical implies admitting the probability of error. Therefore, since it is
possible we are wrong, we must seek evidence for our judgments about facts.
Furthermore, we must know that what is considered evidence today may not be
evidence tomorrow. After all, we are confined within a specific time and place,
to say the least.
References
1. Kuhn, T. S. The Structure of Scientific Revolutions. 3rd ed. The University Chicago Press, 1996.
2. Kuhn, T. S. The Structure of Scientific Revolutions. 2nd ed., University of Chicago Press, Chicago & London, 1970, p.175.
3. KATZ, J. Experimentation with human beings. New York: Russel Sage Foundation. 1973.
4. VIEIRA, S. e HOSSNE, W. S. Experimentação com seres humanos. São Paulo: Moderna, 1986.
