Overview & Questions on Thomas Kuhn's 1969 Postscript to The Structure of Scientific Revolutions
Thomas Kuhn's 1969 postscript to his The Structure of Scientific Revolutions was intended to answer critics of the book primarily in regards to three charges:
  1. That the book suffers from a lack of development and clarity as to its primary metaphor, "paradigm;"
  2. That Kuhn's position is relativistic;
  3. That Kuhn confuses descriptive and normative analysis of science.

The majority of his time is spent in answering the first charge. He does this by centering in on two meanings of "paradigm" and the implications of these meanings to his theory:

On the one hand, it stands for the entire constellation of beliefs, values, techniques, and so on shared by the members of a given community.  On the other, it denotes one sort of element in that constellation, the concrete puzzle-solutions which, employed as models or examples, can replace explicit rules as a basis for the solution of the remaining puzzles of normal science.  The first sense of the term, call it the sociological . . . [while the second is] devoted to paradigms as exemplary past achievements.

To show the value in these two approaches, he refines a number of aspects in his analysis:

  • While the scientific communities can be discussed without reference to their paradigms, those paradigms are what the members share and, therefore, are what set them apart.
  • Scientific communities are demarcated at various levels--from the most global to the  subdisciplinary. 
  • Community structures do change over time; for example, the content of a single discipline now may have at points in the past been distributed over a number of disciplines.
  • A "disciplinary matrix" is made up of those elements that are required for professional inclusion.
  • "Symbolic generalizations" are those assumptions that can be expressed in logical expressions which are shared by the discipline and that function as "laws" but more often as "definitions" or tautologies. Revolutions tend to call into question what were previously tautologies.
  • The "metaphysical" elements of paradigms simply means the shared beliefs that provide a community its unquestioned metaphors, analogies, and models.
  • A scientific discipline's values include a commitment to simplicity, self-consistency, plausibility, and so forth in evaluating its theories, even though these values work themselves out differently in each individual person's application.
  • This difference in response is what makes both the stability of normal science and the questioning of anomalies possible.
  • Training new scientists through shared exemplars is what makes it possible to acquire the faculty of seeing a current problem as like another one. This knowledge, then, is made possible through concrete situations not through learning general laws.
  • Group intuitions are what make group membership a working reality, and such knowledge is analyzable because it is embedded in its shared exemplars.

Kuhn's answer to the second charge is to stress that just because differing paradigm communities are incommensurable, it doesn't follow that communication is impossible. Things shared in common permit communication, but one should remember that the shared vocabulary of the differing communities may also reveal a fundamental difference in understanding. Likewise, the process of translating between the differing viewpoints doesn't commit someone to internalizing the other viewpoint as one's own, but it does create a situation in which the gestalt switch from one way of seeing to another is made possible. Using an "evolutionary tree" image, Kuhn insists that he is not a relativist if that commits him to saying that no scientific progress is possible. However, he also admits that he is a relativist if this means that "[t]here is, I think, no theory-independent way to reconstruct phrases like 'really there'; the notion of a match between the ontology of a theory and its 'real' counterpart in nature now seems to me illusive in principle."

To the third charge, he insists that the descriptive and the proscriptive overlap in best practice. A study of the history of science carries with it an attempt to understand the most successful.


  1. Is Kuhn a relativist? Is he an antirealist? Explain.
  2. Does a removal of a telos from science give up too much? Why would it not?
  3. Does Kuhn's defense of exemplars contradict his analysis of how textbooks and scientific education give an illusion of singular discoveries and of cumulative findings?
  4. Why does Kuhn seem to distance himself from the his earlier language of "metaphysics," "mystical aesthetic," and "conversion experience"?
  5. Has Kuhn, by using his evolutionary tree image, reversed himself in regards to his views of scientific progress?
  6. Is Kuhn's notion of a paradigm shift applicable to other fields? Has it rightly been adopted?
  7. Is it possible to separate out the normative and the descriptive? Explain.

"All manner of thing shall be well/ When the tongues of flame are in-folded/ Into the crowned knot of fire/ And the fire and the rose are one." -- T.S. Eliot, Little Gidding