Kuhn lays out the aim of his book: he wants to use history to change the way science is viewed and understood. In particular, he hopes to counteract the simplistic narrative that scientific textbooks present. Kuhn argues that these textbooks tell a linear—and misleading—history of progress, in which scientists move away from error and toward a correct set of tools, techniques and concept.
Right away, Kuhn introduces two key elements of his argument: first, he is pushing back against a dominant narrative of scientific progress, which suggests that scientific discovery moves in a straight line toward truth. Second, he suggests that as a historian, he has an active role in shaping how science is viewed. As the book continues, it is important to remember that Kuhn is always trying to shift the way scientists, historians, and philosophers think.
Recently, historians have been finding it difficult to write this kind of textbook history. For one, scientific discovery is not always chronological, nor is it always easy to ascribe to one person. In addition, current views of nature are not actually any more or less “scientific” than the now-discounted views of the past. Kuhn thus argues that “if these out-of-date beliefs are to be called myths, then myths can be produced by the same sorts of methods and held for the same sorts of reasons that now produce scientific knowledge.”
As he moves through history, Kuhn emphasizes that many currently discredited theories were at one time considered to be highly scientific and precise. If that is the case, then the theories people today hold up as factual might be discredited by future generations and thought of as “out-of-date,” similar to the way that many old beliefs are now thought of as fictional “myths.” Kuhn thus blurs the line between objective science and creative myth.
As historians struggle with this problem, Kuhn suggests that “a historiographic revolution in the study of science” is already underway. Rather than studying scientists’ work in relation to modern science, historians now study that work in the context of its own time. And rather than trying to invalidate past scientists, historians have started to try to understand them.
Though this book has some radical ideas, Kuhn was not alone in doing this kind of work. Many historians in the 1960s (when he was writing) were also trying to view intellectual history less through the lens of the present and more on its own terms. Kuhn’s use of the word “revolution” is also interesting, as it links his project (a “historiographic” revolution) to the scientific revolutions that give the book its name.
Kuhn describes the “new image of science” that he and his fellow historians are trying to create. First, he wants to de-emphasize method as the main criterion of accuracy. Many scientists use legitimate methods, but their results differ because they have different expectations and beliefs. Kuhn then proposes that there is always something “arbitrary” in the expectations or areas of interest that inform scientific discovery. At the same time, that arbitrariness is necessary for scientists, as it allows them to ask focused questions about nature and to build on one another’s work.
As he will continue to do throughout the treatise, Kuhn emphasizes that scientists are always guided by their particular beliefs about which facts are more important than others. These beliefs, grounded in scientists’ particular education and life experience, are always somewhat “arbitrary”; the science that results from them, then, can never be fully objective.
The process by which these arbitrary assumptions are passed down through formal education is, in Kuhn’s words, “normal science.” Normal science “is predicated on the assumption that the scientific community knows what the world is like.” It follows, then, that normal science does not encourage—and sometimes actively suppresses—new or divergent ways of thinking about the natural world.
Though scientists’ beliefs may be arbitrary, they are also often shared by large groups. A major thread of Kuhn’s argument is that science education, built on textbooks and problem-solving, teaches young scientists to adopt their elders’ arbitrary beliefs. But while this textbook education allows for continuity, it leaves little room for invention or new thought. Instead, scientists tend to assume that they already “know what the world is like.”
There are some moments, however, when trying to use normal science to solve a problem is impossible. In these moments, scientists question their received (“arbitrary”) assumptions, and they focus their attention in new ways or go back to the drawing board entirely. This is what Kuhn terms “a scientific revolution.” Scientific revolutions cause scientists (and often the broader population) to view and experience the world differently.
Sometimes, the beliefs or expectations handed down through textbooks blatantly clash with reality (and Kuhn will later provide ample historical evidence to back up this claim). To Kuhn, these clashes—“crises,” as he calls them—are the most important, least studied element of scientific history.
There have been many scientific revolutions throughout history. Several of the most well-known revolutions are associated with scientists Nicolaus Copernicus, Isaac Newton, Antoine Lavoisier, and Albert Einstein. However, Kuhn believes that many less famous scientific revolutions are equally important.
Copernicus argued that Earth revolved around the sun, not the other way around. Newton introduced the idea of gravity and formulated crucial laws of physics. Lavoisier made important contributions to chemistry, particularly around the discovery of oxygen. Einstein is perhaps most famous for his theory of relativity, which linked space and time. Kuhn lists these well-known scientists together to emphasize his point that scientific progress isn’t linear—instead, it’s a constant cycle of revolutions, all of which are important.
Rather than a narrative of incremental progress, then, Kuhn sees scientific history as a cycle: scientific revolutions interrupt normal science, which leads to a new kind of normal science, which is then interrupted again, and so on. Kuhn acknowledges that history is often viewed more as a description than as a field that can cause “conceptual transformation.” Yet he feels that his “circular” understanding of the history of science has “something important to tell us.”
There are two crucial things to note here: first, if textbooks depict the history of science as a straight line, Kuhn sees it as a circle. Second, Kuhn again emphasizes that historians like himself have the ability to alter “something important” about how people understand the present.