Thomas Kuhn

Science as a Paradigm

Thomas Kuhn attacks “development-by-accumulation” views of science which hold that science progresses linearly by accumulation of theory-independent facts.  Older theories give way successively to wider, more inclusive ones.

Kuhn was critical of the simplistic picture that philosophers had painted of science. Kuhn looked at the history of science and argued that science does not simply progress by stages based upon neutral observations (e.g. Positivism). 

Like Karl Popper, he agrees that all observation is theory laden.  Scientists have a worldview or "paradigm".  The paradigm of Newton's mechanical universe is very different to the paradigm of Einstein's relativistic universe; each paradigm is an interpretation of the world, rather than an objective explanation.  Darwin is also an example of a paradigm shift in biology.

For Kuhn the history of science is characterized by revolutions in scientific outlook. Scientists accept the dominant paradigm until anomalies are thrown up.  Scientists then begin to question the basis of the paradigm itself, new theories emerge which challenge the dominant paradigm and eventually one of these new theories becomes accepted as the new paradigm.

He believes that we progress intellectually through stages of development.  This can be related to Piaget’s Stage Theory account of cognitive development in children.

During different periods of science, certain perspectives held sway over the thinking of researchers.  A particular work may “define the legitimate problems and methods of a research field for succeeding generations of practitioners.”

Knowledge which does not evolve according to the four stages, according to Kuhn, may not be considered scientific.

Pre-science

• Disorganized and diverse activity.
• Constant debate over fundamentals.
• As many theories as there are theorists.
• No commonly accepted observational basis. The conflicting theories are constituted with their own set of theory-dependent observations.

Normal Science (most common – science is usually stable)

• A paradigm is established which lays the foundations for legitimate work within the discipline. Scientific work then consists in articulation of the paradigm, in solving puzzles that it throws up.
• Puzzles that resist solution are seen as anomalies.
• Anomalies are tolerated and do not cause the rejection of the theory.
• A paradigm is a conventional basis for research; it sets a precedent.
• It is necessary for normal science to be uncritical. If all scientists were critical of a theory and spent time trying to falsify it, no detailed work would ever get done.

Crisis and Revolution

• Anomalies become serious, and a crisis develops if the anomalies undermine the basic assumptions of the paradigm and attempts to remove them consistently fail.
• Under these circumstances the rules for the application of the paradigm become relaxed. Ideas that challenge the existing paradigm are developed.
• Eventually a new paradigm will be established, but not as a result of any logically compelling justification.
• In crisis there will be ‘extraordinary science’ where there will be several competing theories.
  One theory will win because it will get the greatest number of supporters in the scientific community, because it is simple or may solve a social need.

New Paradigm

• Each paradigm constructs “the Universe” and the meaning of concepts and observations in a completely different way.
• Each paradigm comes complete with standards for the assessment of what is to count as scientific.
• Different paradigms are held to be incommensurable.
• The reasons for the choice of a paradigm are largely psychological and sociological.
• There is no natural measure or scale for ranking different paradigms.

A paradigm is a universally recognizable scientific achievement that, for a time, provides model problems and solutions to a community of practitioners.

The enormous impact of Thomas Kuhn's work can be measured in the changes it brought about in the vocabulary of the philosophy of science: besides "paradigm shift", Kuhn raised the word "paradigm" itself from a term used in certain forms of linguistics to its current broader meaning. The frequent use of the phrase "paradigm shift" has made scientists more aware of and in many cases more receptive to paradigm changes, so that Kuhn’s analysis of the evolution of scientific views has by itself influenced that evolution.

For Kuhn, the choice of paradigm was sustained by, but not ultimately determined by, logical processes.  Kuhn believed that it represented the consensus of the community of scientists. Acceptance or rejection of some paradigm is, he argued, a social process as much as a logical process. This means Kuhn is a relativist, although he denies this stating that a scientific theory can be assessed according to its problem solving ability.

Does science make progress through scientific revolutions?  Are later paradigms better than earlier ones? No, Kuhn suggests, they are just different.  The scientific revolutions which supplant one paradigm with another do not take us closer to the truth about the way the world is. 

Successive paradigms are INCOMMENSURABLE.  Kuhn says that a later paradigm may be a better instrument for solving puzzles than an earlier one.  But if each paradigm defines its own puzzles, what is a puzzle for one paradigm may be no puzzle at all for another.  So why is it progress to replace one paradigm with another which solves puzzles that the earlier paradigm does not even recognize? Kuhn used his incommensurability thesis to disprove the view the paradigm shifts are objective. Truth is relative to the paradigm.

Science does not change its paradigm over night. Younger scientists take new paradigm forward. As Kuhn put it "a new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it."

Evaluation: Thomas Kuhn showed contemporary philosophers could not ignore the history of science and the social context which science takes place.  Science is a product of the society in which it is practiced.

Is psychology a pre-science? Was there a cognitive revolution from behaviorism that changed methodology and assumptions? Is cog a new paradigm?  Still reductionist, input – output, still uses experimental method.

Further Information

Karl Popper - Falsification

What is Science

Psychology as a Science

How to cite this article: McLeod, S. A. (2010). Simply Psychology; . Retrieved from