The philosopher Thomas Kuhn transformed the way educated people think about the growth of scientific knowledge when he introduced the concept of the "paradigm" in his landmark work "The Structure of Scientific Revolutions" (1962). Before Kuhn, the prevailing view of scientific progress — associated with the logical positivists and popularised by Karl Popper — was essentially cumulative and rational: science advanced through the steady accumulation of verified facts or, in Popper's more sophisticated account, through the systematic falsification of bold hypotheses. On either account, the history of science was a story of progressive enlightenment, with each generation inheriting a more complete and accurate picture of reality than its predecessors. Kuhn challenged this narrative not by questioning the achievements of science but by examining how scientists actually behave — the sociology as much as the logic of scientific change.

Kuhn introduced a distinction between "normal science" and "revolutionary science." Normal science, which accounts for the vast majority of scientific activity, takes place within an accepted paradigm — a framework of assumptions, methods, and exemplary achievements that defines what counts as a legitimate scientific problem and a satisfactory solution. Scientists working within a paradigm do not fundamentally question its premises; they use its tools to solve the "puzzles" it generates, in much the same way that crossword solvers use the rules of the puzzle rather than questioning the conventions of the English language. The anomalies that occasionally appear — results that cannot be explained within the existing framework — are initially dismissed, minimised, or set aside as puzzles awaiting solution rather than as evidence that the paradigm itself is flawed.

Scientific revolutions occur when anomalies accumulate to the point where a growing community of practitioners begins to experience what Kuhn called a "crisis." In a crisis, the normal puzzle-solving confidence of scientists breaks down, foundational questions are reopened, and proliferating theories compete for primacy. The transition to a new paradigm — what Kuhn called a "paradigm shift" — does not happen through the calm application of logical rules. It is more akin to a gestalt switch: a sudden reorganisation of perception that allows the scientist to see the same data in a fundamentally different light. The heliocentric revolution, the Darwinian revolution in biology, and the quantum mechanical revolution in physics all involved not merely the addition of new facts but the wholesale restructuring of the conceptual landscape within which facts are understood and valued.

Kuhn's most provocative claim was that successive paradigms are "incommensurable" — not merely different but incomparable in any straightforward sense, because they carve up reality differently and define the very terms in which evidence is gathered and interpreted. Newtonian mechanics and Einsteinian relativity, for instance, use the same word "mass" but mean fundamentally different things by it. If Kuhn is right, there can be no neutral observation language standing outside all paradigms that would allow us to adjudicate between them on purely evidential grounds. Scientific progress is real, but it is not a simple accumulation; it involves the abandonment of entire frameworks of understanding, and what is gained in the transition is not always straightforwardly comparable with what is lost.

Kuhn's framework has been enormously influential beyond the philosophy of science, shaping debates in history, sociology, literary theory, and political thought. Yet it has also attracted persistent criticism. Critics argue that the incommensurability thesis, taken seriously, would make science irrational — a matter of sociological conversion rather than evidence-driven persuasion. Kuhn himself insisted he was not advocating relativism about scientific truth but simply providing a more accurate description of how science works in practice. The debate he initiated between those who emphasise the rationality of science and those who emphasise its social and historical embeddedness remains one of the most productive tensions in contemporary philosophy of science.

1. According to Paragraph 1, what was the prevailing view of scientific progress before Kuhn?
   • A. That science advanced through the steady accumulation of verified facts or the systematic falsification of bold hypotheses. ✓
   • B. That scientific revolutions were the primary driver of knowledge, with normal science acting as mere consolidation.
   • C. That science was primarily a social activity shaped by the institutional interests of research communities.
   • D. That paradigm shifts, not incremental accumulation, explained the most significant advances in scientific history.

   Paragraph 1 states: 'the prevailing view of scientific progress... was essentially cumulative and rational: science advanced through the steady accumulation of verified facts or, in Popper's more sophisticated account, through the systematic falsification of bold hypotheses.' Option A is a direct paraphrase. Options B, C, and D describe Kuhnian ideas or post-Kuhnian positions, not the pre-Kuhnian orthodoxy described in Paragraph 1.

2. According to Paragraph 2, how do scientists working within a paradigm typically respond to anomalies that cannot be explained by the existing framework?
   • A. By immediately forming competing schools of thought that advocate alternative paradigmatic frameworks.
   • B. By dismissing, minimising, or setting them aside as puzzles awaiting future solution rather than as evidence against the paradigm. ✓
   • C. By publishing anomalies in specialised journals where they accumulate until a critical mass triggers revolutionary change.
   • D. By appealing to foundational principles of the paradigm to reinterpret the anomalies as consistent with its predictions.

   Paragraph 2 states: 'The anomalies that occasionally appear... are initially dismissed, minimised, or set aside as puzzles awaiting solution rather than as evidence that the paradigm itself is flawed.' Option B is a direct paraphrase. Options A, C, and D describe responses not specified in Paragraph 2.

3. According to Paragraph 4, what does Kuhn mean by claiming that successive paradigms are 'incommensurable'?
   • A. That older paradigms are invariably superseded by newer ones that retain none of their original conceptual content.
   • B. That paradigm shifts occur too rapidly for scientists within the older framework to evaluate the new one fairly.
   • C. That successive paradigms carve up reality differently, making straightforward comparison on neutral evidential grounds impossible. ✓
   • D. That only practitioners trained within a new paradigm can understand its claims, making inter-generational dialogue impossible.

   Paragraph 4 states: 'Kuhn's most provocative claim was that successive paradigms are incommensurable — not merely different but incomparable in any straightforward sense, because they carve up reality differently and define the very terms in which evidence is gathered and interpreted.' Option C directly paraphrases this claim. Options A, B, and D mischaracterise or extend the incommensurability thesis beyond what the passage states.

4. What does the author imply by comparing normal science to solving crossword puzzles in Paragraph 2?
   • A. That normal science is intellectually trivial and contributes little to the overall advancement of knowledge.
   • B. That normal science operates within pre-given rules and conventions rather than questioning the framework that generates its problems. ✓
   • C. That scientific puzzles, like crosswords, always have determinate correct answers reachable through sufficient disciplinary effort.
   • D. That scientists are primarily motivated by competitive puzzle-solving rather than by genuine commitment to truth.

   Paragraph 2 compares scientists working within a paradigm to crossword solvers 'who use the rules of the puzzle rather than questioning the conventions of the English language.' The analogy implies that normal science accepts its framework as given and works within it rather than questioning its foundations — matching option B. Option A overstates — the passage does not call normal science trivial. Options C and D draw inferences that go beyond the analogy's stated purpose.

5. What can be inferred from Paragraph 5 about Kuhn's own position on scientific relativism?
   • A. That Kuhn fully embraced relativism, arguing that different paradigms represent equally valid but incompatible perspectives on reality.
   • B. That Kuhn was agnostic about scientific truth, neither affirming nor denying that science makes genuine progress.
   • C. That Kuhn rejected the relativist interpretation of his work, insisting his aim was descriptive accuracy rather than philosophical relativism about truth. ✓
   • D. That Kuhn initially accepted relativism but retreated from it in later work in response to persistent criticism from scientists.

   Paragraph 5 states: 'Kuhn himself insisted he was not advocating relativism about scientific truth but simply providing a more accurate description of how science works in practice.' Option C directly paraphrases this. Options A and B misattribute relativist or agnostic positions the passage explicitly says Kuhn rejected; option D invents a biographical shift not discussed in the passage.