The Structure of Scientific Revolutions
The Structure of Scientific Revolutions is a 1962 book about the history of science by the philosopher Thomas S. Kuhn. Its publication was a landmark event in the history, philosophy, and sociology of science. Kuhn challenged the then prevailing view of progress in science in which scientific progress was viewed as "development-by-accumulation" of accepted facts and theories. Kuhn argued for an episodic model in which periods of conceptual continuity and cumulative progress, referred to as periods of "normal science", were interrupted by periods of revolutionary science. The discovery of "anomalies" accumulating and precipitating revolutions in science leads to new paradigms. New paradigms then ask new questions of old data, move beyond the mere "puzzle-solving" of the previous paradigm, alter the rules of the game and change the "map" directing new research.
For example, Kuhn's analysis of the Copernican Revolution emphasized that, in its beginning, it did not offer more accurate predictions of celestial events, such as planetary positions, than the Ptolemaic system, but instead appealed to some practitioners based on a promise of better, simpler solutions that might be developed at some point in the future. Kuhn called the core concepts of an ascendant revolution its "paradigms" and thereby launched this word into widespread analogical use in the second half of the 20th century. Kuhn's insistence that a paradigm shift was a mélange of sociology, enthusiasm and scientific promise, but not a logically determinate procedure, caused an uproar in reaction to his work. Kuhn addressed concerns in the 1969 postscript to the second edition. For some commentators The Structure of Scientific Revolutions introduced a realistic humanism into the core of science, while for others the nobility of science was tarnished by Kuhn's introduction of an irrational element into the heart of its greatest achievements.
History
The Structure of Scientific Revolutions was first published as a monograph in the International Encyclopedia of Unified Science, then as a book by University of Chicago Press in 1962. In 1969, Kuhn added a postscript to the book in which he replied to critical responses to the first edition. A 50th Anniversary Edition was published by the University of Chicago Press in April 2012.Kuhn dated the genesis of his book to 1947, when he was a graduate student at Harvard University and had been asked to teach a science class for humanities undergraduates with a focus on historical case studies. Kuhn later commented that until then, "I'd never read an old document in science." Aristotle's Physics was astonishingly unlike Isaac Newton's work in its concepts of matter and motion. Kuhn wrote: "as I was reading him, Aristotle appeared not only ignorant of mechanics, but a dreadfully bad physical scientist as well. About motion, in particular, his writings seemed to me full of egregious errors, both of logic and of observation." This was in an apparent contradiction with the fact that Aristotle was a brilliant mind. While perusing Aristotle's Physics, Kuhn formed the view that in order to properly appreciate Aristotle's reasoning, one must be aware of the scientific conventions of the time. Kuhn concluded that Aristotle's concepts were not "bad Newton," just different. This insight was the foundation of The Structure of Scientific Revolutions.
Central ideas regarding the process of scientific investigation and discovery had been anticipated by Ludwik Fleck in. Fleck had developed the first system of the sociology of scientific knowledge. He claimed that the exchange of ideas led to the establishment of a thought collective, which, when developed sufficiently, separated the field into esoteric and exoteric circles. Kuhn wrote the foreword to the 1979 edition of Fleck's book, noting that he read it in 1950 and was reassured that someone "saw in the history of science what I myself was finding there."
Kuhn was not confident about how his book would be received. Harvard University had denied his tenure a few years prior. By the mid-1980s, however, his book had achieved blockbuster status. When Kuhn's book came out in the early 1960s, "structure" was an intellectually popular word in many fields in the humanities and social sciences, including linguistics and anthropology, appealing in its idea that complex phenomena could reveal or be studied through basic, simpler structures. Kuhn's book contributed to that idea.
One theory to which Kuhn replies directly is Karl Popper's "falsificationism," which stresses falsifiability as the most important criterion for distinguishing between that which is scientific and that which is unscientific. Kuhn also addresses verificationism, a philosophical movement that emerged in the 1920s among logical positivists. The verifiability principle claims that meaningful statements must be supported by empirical evidence or logical requirements.
Synopsis
Basic approach
Kuhn's approach to the history and philosophy of science addresses conceptual issues like the practice of normal science, influence of historical events, emergence of scientific discoveries, nature of scientific revolutions and progress through scientific revolutions. What sorts of intellectual options and strategies were available to people during a given period? What types of lexicons and terminology were known and employed during certain epochs? Stressing the importance of not attributing traditional thought to earlier investigators, Kuhn's book argues that the evolution of scientific theory does not emerge from the straightforward accumulation of facts, but rather from a set of changing intellectual circumstances and possibilities.Kuhn did not see scientific theory as proceeding linearly from an objective, unbiased accumulation of all available data, but rather as paradigm-driven:
Historical examples of chemistry
Kuhn explains his ideas using examples taken from the history of science. For instance, eighteenth-century scientists believed that homogenous solutions were chemical compounds. Therefore, a combination of water and alcohol was generally classified as a compound. Nowadays it is considered to be a solution, but there was no reason then to suspect that it was not a compound. Water and alcohol would not separate spontaneously, nor will they separate completely upon distillation. Water and alcohol can be combined in any proportion.Under this paradigm, scientists believed that chemical reactions did not necessarily occur in fixed proportion. This belief was ultimately overturned by Dalton's atomic theory, which asserted that atoms can only combine in simple, whole-number ratios. Under this new paradigm, any reaction which did not occur in fixed proportion could not be a chemical process. This type of world-view transition among the scientific community exemplifies Kuhn's paradigm shift.
Examples from applied microbiology
In 1860 Louis Pasteur published experimental results proving that fermentation was caused by microorganisms, instead of some self-starting chemical reaction, which was the reigning theory. As summarized by science writer Charles Mann, "Pasteur’s work led to a pitched intellectual battle—and the eventual triumph of germ theory, which overturned earlier ideas about infectious disease." Mann continues:
Pasteur’s work on the role of microorganisms in infectious disease inaugurated the modern discipline of microbiology—and led to a host of about-faces in previous medical beliefs. German researcher Robert Koch, often considered microbiology’s co-founder, then discovered the microbes that caused anthrax, cholera and tuberculosis. All cast aside earlier ideas. For instance, many in Koch’s Germany believed tuberculosis was a hereditary disease passed down through families until 1882, when the scientist unveiled Mycobacterium tuberculosis, the bacterium responsible for the disease.
While paradigm shifts in the physical and chemical sciences can greatly affect how technologies evolve in societally impactful ways, anything pertaining to the wellbeing of human bodies can easily become politicized. Mann offers examples pertaining to the decades long controversy over the age threshold recommended for regular breast cancer screenings and to the initial World Health Organization pronouncement in 2020 that COVID-19 could not be transmitted through the air. Government policies and mandates issued to thwart the COVID-19 pandemic were in part impelled by scientific understandings that were later overturned.
Copernican Revolution
A famous example of a revolution in scientific thought is the Copernican Revolution. In Ptolemy's school of thought, cycles and epicycles were used for modeling the movements of the planets in a cosmos that had a stationary Earth at its center. As accuracy of celestial observations increased, complexity of the Ptolemaic cyclical and epicyclical mechanisms had to increase to maintain the calculated planetary positions close to the observed positions. Copernicus proposed a cosmology in which the Sun was at the center and the Earth was one of the planets revolving around it. For modeling the planetary motions, Copernicus used the tools he was familiar with, namely the cycles and epicycles of the Ptolemaic toolbox. Yet Copernicus' model needed more cycles and epicycles than existed in the then-current Ptolemaic model, and due to a lack of accuracy in calculations, his model did not appear to provide more accurate predictions than the Ptolemy model. Copernicus' contemporaries rejected his cosmology, and Kuhn asserts that they were quite right to do so: Copernicus' cosmology lacked credibility.Kuhn illustrates how a paradigm shift later became possible when Galileo Galilei introduced his new ideas concerning motion. Intuitively, when an object is set in motion, it soon comes to a halt. A well-made cart may travel a long distance before it stops, but unless something keeps pushing it, it will eventually stop moving. Aristotle had argued that this was presumably a fundamental property of nature: for the motion of an object to be sustained, it must continue to be pushed. Given the knowledge available at the time, this represented sensible, reasonable thinking.
Galileo put forward a bold alternative conjecture: suppose, he said, that we always observe objects coming to a halt simply because some friction is always occurring. Galileo had no equipment with which to objectively confirm his conjecture, but he suggested that without any friction to slow down an object in motion, its inherent tendency is to maintain its speed without the application of any additional force.
The Ptolemaic approach of using cycles and epicycles was becoming strained: there seemed to be no end to the mushrooming growth in complexity required to account for the observable phenomena. Johannes Kepler was the first person to abandon the tools of the Ptolemaic paradigm. He started to explore the possibility that the planet Mars might have an elliptical orbit rather than a circular one. Clearly, the angular velocity could not be constant, but it proved very difficult to find the formula describing the rate of change of the planet's angular velocity. After many years of calculations, Kepler arrived at what we now know as the law of equal areas.
Galileo's conjecture was merely that – a conjecture. So was Kepler's cosmology. But each conjecture increased the credibility of the other, and together, they changed the prevailing perceptions of the scientific community. Later, Newton showed that Kepler's three laws could all be derived from a single theory of motion and planetary motion. Newton solidified and unified the paradigm shift that Galileo and Kepler had initiated.