The Structure of Scientific Revolutions | Study Guide

Thomas Kuhn

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The Structure of Scientific Revolutions | Quotes


In the mature sciences, answers ... are firmly embedded in the educational initiation.

Narrator, Chapter 1

Kuhn identified his philosophy while creating a course for undergraduates and reading primary texts. Therefore, he introduces his reader to his philosophy the same way. He was struck by the way scientific students were taught. They were not instructed in the history of their discipline, but were instead presented with scientific theories and methods as givens, despite a long history of discussion, debate, and change that led to their development.


Examples of scientific revolutions are ... episodes in scientific development that have ... been labeled revolutions before.

Narrator, Chapter 1

Kuhn does not invent the notion of a scientific revolution. He cites many historical examples. Instead, he argues science develops by means of the scientific revolution, not, as the textbooks purport, by means of the accumulation of knowledge in some linear, progressive fashion. Scientific knowledge and methods are continually being overthrown and replaced. That is, in fact, how science works.


'Normal science' means research firmly based upon one or more past scientific achievements.

Narrator, Chapter 2

The activity in which most scientists engage for most of their professional lives is not discovery. Instead, it involves solving problems identified by an already-defined significant scientific achievement.


In the absence of a paradigm ... all of the facts ... seem equally relevant.

Narrator, Chapter 2

Without a paradigm scientists would be engaged only in the accumulation of facts, and their work would result only in a set of reference works, like one great encyclopedia. Paradigms are those scientific achievements that organize and direct normal science. Without one there is no standard by which to evaluate the facts or to determine their significance.


Paradigms gain their status because they are more successful than their competitors in solving ... problems.

Narrator, Chapter 3

The best theories win out because they best explain the phenomena in need of explanation.


[Normal science] seems an attempt to force nature into the preformed ... box ... the paradigm supplies.

Narrator, Chapter 3

The normal science in which most scientists are engaged serves to test the paradigm. It does not so much reveal a truth about nature as it reveals a truth about the paradigm.


A paradigm [provides] a criterion for choosing problems that ... can be assumed to have solutions.

Narrator, Chapter 4

The paradigm not only explains a phenomenon; it also identifies the scope of a scientist's work. In Kuhn's theory scientists do not have infinite choice about which subjects to study. They are bound by the paradigms of their time and can only choose to work within them.


Rules ... derive from paradigms, but paradigms can guide research even in the absence of rules.

Narrator, Chapter 4

A scientific theory typically generates the rules that guide the investigation of puzzles. However, they can also serve as the rules themselves.


Awareness of anomaly [is] the recognition ... nature ... violated the paradigm-induced expectations [governing] normal science.

Narrator, Chapter 6

Confrontation with a phenomenon that is unexplainable under the current paradigm is the potential first step in a scientific revolution. Kuhn calls the unexplainable phenomenon an anomaly.


A novel theory emerged only after a pronounced failure in the normal problem-solving activity.

Narrator, Chapter 7

When working within an existing paradigm consistently yields a failure to explain the anomaly, the paradigm itself is found to be flawed. Only then can a new theory, or paradigm, emerge.


There is no such thing as research in the absence of any paradigm.

Narrator, Chapter 8

Kuhn makes an important distinction between research and what we might call discovery. Discovery is the mere accumulation of facts, such as the existence of the equator or its length. Kuhn does not consider discovery to be science, or what he calls research. Research requires a paradigm, or what Aristotle might refer to as a telos, a description of an end, meaning, or purpose, rather than mechanics or operations. For Kuhn research sets forth a hypothesis within the parameters established by a paradigm and uses its methodology to test it.


The normal scientific tradition that emerges from a scientific revolution is ... incommensurable with [what] has gone before.

Narrator, Chapter 9

In this case "the normal scientific tradition" is equivalent to a paradigm. Paradigms are called into question because of anomalies: facts, theories, or methods that conflict with paradigms. The very existence of an anomaly proves the fallibility of a paradigm. Therefore, a paradigm that explains the anomaly must be incompatible with a paradigm that exposed the anomaly. For this reason paradigms are "incommensurable."


What were ducks in the scientist's world before the revolution are rabbits afterward.

Narrator, Chapter 10

In a famous picture one person sees a duck and another sees a rabbit. Kuhn describes scientific revolutions as altering the perspective of scientists, much like the viewer of the picture who sees it from different perspectives. Both are always present, but the scientist/viewer can only comprehend one perspective at a time.


["Paradigm"] stands for the entire constellation of beliefs, values, techniques, and so on.

Narrator, Postscript—1969

Kuhn reflects upon the vagueness of the term, paradigm. It is one of the central concepts in the book, but is used in myriad ways. Consequently, Kuhn wants to clarify what he means by the term. Here, his focus is on the sociological meaning of "paradigm," where the focus is on the members of the community working within it.


["Paradigm"] denotes one ... element ... which ... can replace ... rules as a basis for the solution of ... puzzles.

Narrator, Postscript—1969

Here Kuhn considers another definition of the term, paradigm. Here his focus is on one of the features of the community's practices, namely the paradigm as a guide to scientific activity.

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