Linear Progress vs. Circular History Theme Analysis

From physics to chemistry to biology, science textbooks tend to present the history of science as a linear story of progress. Thomas Kuhn, a historian who first trained as a physicist, argues the opposite: in The Structure of Scientific Revolutions, he suggests that each great scientific discovery ushers in a new way of looking at the world (what Kuhn calls a paradigm), which then prompts a new set of scientific questions and techniques. Rather than building on the last paradigm, each new paradigm completely upends the last. Then, the new paradigm undergoes the same cycle of invention, problem-solving, crisis, and collapse. In viewing the history of science as cyclical rather than linear, Kuhn argues that science is more dependent on historical context than textbooks make it seem—in part because scientists themselves are invested in presenting their work as objective and correct rather than as one of many possible ways of tackling a problem.  

Though textbooks present a linear history of science, Kuhn argues that each new paradigm in fact marks a complete break from the one before it. Textbooks tend to suggest that scientific progress is both linear and coherent—for example, by presenting Albert Einstein’s physics as a direct descendant of Isaac Newton’s. Kuhn, however, feels that Newton and Einstein are actually operating under two completely different paradigms. Though the two men used some of the same terms (“space,” “time,” and “mass,” for instance), those words meant very different things to them, and to force Einstein’s worldview onto Newton’s earlier research is to distort the true meaning of his work. Kuhn therefore sees this insistence on linear history as harmful: “by disguising such changes,” he argues, “the textbook tendency to make the development of science linear hides a process that lies at the heart of the most significant episodes of scientific development.” Kuhn believes that new paradigms—and the new beliefs and experiences that go along with them—are the most essential part of understanding how scientific research grows and shifts. To suggest that each scientist is thinking along the same lines as his predecessors is to erase the messy, more human reality of how science develops in favor of a deceptively neat narrative. Kuhn further argues that, like the textbooks they learn from, scientists also  tell a linear—but inaccurate—version of their field’s history. As Kuhn writes, “looking at the moon, the convert to Copernicanism does not say ‘I used to see a planet, but now I see a satellite.’ That locution would imply a sense in which the Ptolemaic system once had been correct. Instead, a convert to the new astronomy would say ‘I once took the moon to be […] a planet, but I was mistaken.’” Rather than acknowledging that each paradigm has particular values and viewpoints, scientists erase past perceptions by labeling them errors or mistakes. Kuhn’s project is to show how each view (both pre- and post-Copernican, in this example) is different but equally valid.

Kuhn then demonstrates that each individual paradigm goes through the same life cycle—and that the history of science itself is often more circular than linear. Kuhn advocates for seeing “scientific development as a succession of tradition-bound periods punctuated by non-cumulative breaks.” Time still moves forward, so one period must succeed the others. But Kuhn emphasizes that science is “non-cumulative”; each new crisis breaks-up (“punctuates”) a field’s work, causing it to start over anew instead of to continue on. On a larger scale, science often seems to loop backwards rather than move forward. To exemplify this idea, Kuhn traces the idea of motion as innate from Aristotle through Descartes through Newton. Aristotle’s belief that objects had built-in properties of motion was largely discounted by Descartes’ “mechanico-corpuscular” view, which dictated that all motion was created by various (uniform) particles bumping into one another. But a few decades later, Newton conceived of gravity, an innate type of motion that was quickly and broadly accepted. This cycle in history stands as a testament to Kuhn’s non-linear, looping history of science. Even the structure of Kuhn’s book reflects this cyclical view of time: rather than moving chronologically through science, Kuhn moves through the stages of each scientific revolution. As he moves from chapters like “Normal Science as Puzzle-Solving” to “Anomaly and the Emergence of Scientific Discoveries,” Kuhn maps a single pattern that repeats itself again and again over time. He even provides cross-historical examples for each chapter, tracing Galileo and Newton’s paradigms from their beginnings to their crises to their collapses. By focusing on this repetitive structure, Kuhn trains his readers to think of scientific history as circular repetition, not as linear advancement.

Though scientists try to validate their own paradigm by erasing the ones that have come before, Kuhn insists that a true historian of science must always acknowledge the radical differences between various paradigms of scientific thought. He argues that scientists are particularly likely to rewrite history in their favor, in part because science—which positions itself as objective and grounded fully in the natural world—seems to exist independently from historical context. Because scientists are able to prove their ideas through experiments (and because their work so often has real-world applications), it seems unnecessary to introduce any historical complexity or doubt into their research. But Kuhn makes clear that while he sees scientific discoveries as operating within a cycle, “that circularity does not at all invalidate them. But it does make them parts of a theory and, by doing so, subjects them to the same scrutiny regularly applied to theories in other fields.” In other words, by acknowledging that their field is cyclical and dependent on context, scientists are forced to think more critically about their work—without at all abandoning it. Moreover, Kuhn’s view of scientific history allows each paradigm’s questions and findings to remain useful even after the paradigm itself has been abandoned, thereby expanding (instead of narrowing) what counts as scientific knowledge.