The Structure of Scientific Revolutions

Citation

Kuhn, T. S. (2012). The Structure of Scientific Revolutions (4th ed., 50th anniversary edition; introductory essay by I. Hacking). University of Chicago Press.

Chapter Summary

The book first appeared in 1962 and was extended with a postscript in 1969. This fourth edition keeps Kuhn's text and adds an introductory essay by Ian Hacking, which the publisher describes as clarifying terms such as paradigm and incommensurability and as keyed to the separate sections of the book. The main text consists of a preface, thirteen short chapters and the 1969 postscript, so the book is short enough to read in a few sittings.

Context and Argument

Kuhn argues that science does not grow by the steady accumulation of facts. A mature science works within a shared paradigm; its normal activity is puzzle-solving; persistent anomalies can produce a crisis; and a revolution replaces one paradigm with another in a way that cannot be settled by logic and experiment alone. The chapters follow this cycle in order.

Chapter I: Introduction: A Role for History

The opening chapter argues that history can change the image of science. Kuhn sets aside the picture of science as a linear accumulation of facts and the sharp separation of the context of discovery from the context of justification, and proposes to look at actual episodes of research.

Chapters II–V: The Route to Normal Science; The Nature of Normal Science; Normal Science as Puzzle-solving; The Priority of Paradigms

These chapters describe how a field reaches maturity. In a pre-paradigm period competing schools disagree over fundamentals; a remarkable achievement, often embodied in a text such as Ptolemy's Almagest, Newton's Principia or Lavoisier's chemistry, then draws consensus around it. Normal science works on puzzles the paradigm defines, with confidence that solutions exist. The chapter on the priority of paradigms contrasts shared exemplars with explicit rules as what guides research.

Chapters VI–VIII: Anomaly and the Emergence of Scientific Revolutions; Crisis and the Emergence of Scientific Theories; The Response to Crisis

Anomalies are results that the paradigm fails to accommodate. Most are set aside or absorbed, but when they undermine the practice of normal science a crisis develops. The chapters then describe how scientists respond, including the search for alternatives and the persistence of commitment to the existing paradigm until a credible rival is available.

Chapters IX–XII: The Nature and Necessity of Scientific Revolutions; Revolutions as Changes of World View; The Invisibility of Revolutions; The Resolution of Revolutions

The core chapters argue that revolutions are non-cumulative changes in which something earlier achievements explained may be lost, that scientists after a revolution work in a different world of perception and concepts, that textbooks hide such changes by rewriting history, and that the choice between rival paradigms is made by the scientific community rather than by a rule that compels agreement.

Chapter XIII: Progress through Revolutions

Kuhn asks in what sense science makes progress if revolutions are not cumulative. He argues that a new paradigm must solve outstanding problems and preserve much of the problem-solving power of its predecessor, and he frames progress in evolutionary terms, as improved problem-solving rather than movement toward a final truth.

Postscript-1969

In the postscript Kuhn replies to critics and reworks the term "paradigm," distinguishing the shared commitments of a community (the "disciplinary matrix") from the narrower sense of exemplary problem solutions, and he calls paradigms in this narrower sense the most novel and least understood aspect of the book.

Key Concepts

Normal science

• Paradigm: in the broad sense, the shared commitments of a scientific community; in the narrower sense, exemplary achievements that serve as models for further work.
• Normal science: research based on a paradigm, treated as puzzle-solving.
• Puzzle: a problem whose solution is expected to be possible by familiar methods.

Crisis and revolution

• Anomaly and crisis: a result the paradigm does not accommodate, and a widespread loss of confidence when anomalies undermine normal practice.
• Scientific revolution: a non-cumulative change of paradigm.
• Incommensurability: the claim that rival paradigms differ in concepts, standards and problems so that no neutral comparison is available.
• Kuhn-loss: explanatory achievements that a successor theory does not retain.
• Progress without a goal of truth: improvement understood as increased puzzle-solving power, not nearness to truth.

Critical Analysis

Strengths

• A clear structure. The chapter order follows the cycle it describes, from pre-paradigm science through normal science, crisis and revolution to resolution, so the argument can be followed step by step.
• Range of examples. Reviewing the anniversary edition in Nature, David Kaiser praised Kuhn's "fascinating mix of examples from psychology, history, philosophy, and beyond" and described Hacking's introduction as a helpful guide to some of the thornier philosophical issues.
• Support for readers. Hacking's essay is organized to correspond to the sections of the book and clarifies terms that became common currency, and the 1969 postscript answers criticism and refines the central term.
• A concrete target. Kuhn sets his account against the cumulative picture and against Popper's falsificationism, which gives the book a clear contrast for students to work with.

Limitations

• The picture of scientific change has been disputed. The Stanford Encyclopedia of Philosophy reports Stephen Toulmin's objection that revisionary change is more common and less dramatic than Kuhn supposes, and notes that discoveries such as the structure of DNA do not fit Kuhn's pattern of anomaly followed by crisis.
• Key terms are unstable. Kuhn himself calls paradigms the most novel and least understood aspect of the book, and incommensurability has been criticized as non-existent or as less significant than he claimed; Kuhn's own account of it changed in later work.
• Rooted in physical science. The publisher notes that Kuhn wrote when physics ruled the sciences, and the examples that carry the argument are mainly astronomy, physics and chemistry, so readers from other fields should test the pattern against their own cases.
• Open to misreading. Kuhn's remark that personalities and nationalities can matter in a revolution was developed by some sociologists into the claim that social factors always determine outcomes, a reading Kuhn rejected.

Where It Fits in the Course

This is a primary text on theory change, so it works well after one introductory book and before more specialized ones. Samir Okasha's short introduction and Peter Godfrey-Smith's survey give the setting: Godfrey-Smith follows the century of debate from logical empiricism through Popper, Kuhn, Lakatos and Feyerabend to the sociology of science, so Kuhn appears as one stage in a longer story. Alan Chalmers's book and Alex Rosenberg and Lee McIntyre's textbook both discuss method and theory change and can be used to compare Kuhn with other accounts.

Bas van Fraassen's The Scientific Image is a good partner. Kuhn describes how sciences change and what scientists do within and across paradigms; van Fraassen asks which attitude to adopt toward the theories that result. Reading them together shows how a historical account of theory change and a philosophical account of belief and acceptance can complement each other.

How to Use This Book

The book assumes no technical background, though some acquaintance with the history of science or an introductory philosophy of science course helps.

For a first reading, take the thirteen chapters in order and read the Postscript immediately afterwards, because it clarifies what "paradigm" means and answers common objections. Read Hacking's introductory essay either afterwards, as a commentary, or section by section alongside the book. Chapters II–IV and VI–IX are the core; Chapters X–XI are essential if the course discusses perception, world change or incommensurability; Chapter V can be read more quickly.

A useful exercise is to take a historical episode, such as the shift from Ptolemaic to Copernican astronomy, and place each stage on Kuhn's cycle, then ask which stage is hardest to identify. Compare the result with how Popper's falsificationism would describe the same case, and consider the Stanford Encyclopedia's discussion of criticism of Kuhn's account of scientific change.