Both Thomas S. Kuhn and Karl Popper attempted to construct a theoretical frame which would explain the differences between science and pseudo-science. According to Kuhn, a scientific theory is born through the general consensus of a community of practitioners. This consensus, or paradigm, evolves from previous scientific data. Inside the paradigm, scientists strive to construct a theory that will serve a solution which is known to exist or even empirical data that needs to be supported theoretically. The value of a certain scientific achievement can be verified, in Kuhn’s view, by the existence of a paradigm. A theory is successful as soon as a considerable number of researchers adhere to the paradigm. By contrast, Popper believes that the success of a scientific theory lies, paradoxically, in its refutability and in the risk involved in the initial predictions. Popper thus compares Einstein’s Theory of Relativity with Freud’s psychoanalysis or Marx’s socialism. The philosopher’s conclusion is that Einstein’s theory is truly scientific precisely because it can be proven wrong by empirical observation. Therefore its truth value is verified by the risk of refutability. As opposed to this, Freud’s theory appears to be always right. Its tenets and principles can be applied to an almost unlimited number of divergent cases. Paradoxically, there is too much proof for Freud’s theory for it to be truly scientific. Therefore, Kuhn’s and Popper’s views of science seem to be opposed: Kuhn argues that a theory is scientific when it becomes paradigmatic and attracts a considerable number of scientists in its sphere, while Popper believes that a theory cannot be scientific if it is impossible to contradict it. As it shall be seen, the two philosophers’ views on science are essentially related, although there are also significant differences between their perspectives. Kuhn’s theory of paradigm shift also implies that a certain valuable scientific theory can be refuted by future generations of analysis and research. However, Kuhn believes that a particular science cannot make any progress if it does not become paradigmatic. Popper emphasizes the minds of geniuses like Einstein, who bring innovation in a certain field through intuition and creativity. The conclusions that Kuhn and Popper reach are ultimately similar: both philosophers believe that scientific revolutions are essential realities of scientific research. The dynamics of scientific research is extremely important. In order to be successful, theories should be susceptible to change and evolution.
Kuhn argues that the most salient aspect of scientific evolution in time is the fact that science does not progress through leaps or through unrelated sets of investigations. On the contrary, scientific research is always conducted under a paradigm, or, to put it differently, all research is based on previous scientific data. The scientific paradigm can be defined as a certain common pattern in scientific research, or a certain set of accepted world views that are held as true for a limited period of time. The paradigm is thus a set of common beliefs about the world, based on past research.
According to Kuhn, there is scientific research without paradigms, but this is a sign of immaturity in a certain scientific field (11). When a scientific paradigm establishes itself within a domain it usually means that the respective scientific field has achieved a theory that successfully, although not completely, matches the observable natural phenomena. The way in which a paradigm imposes itself over other possible paradigms has thus two main characteristics in Kuhn’s view: the paradigm is, first of all, sufficiently innovative and able to explain certain phenomena, so as to have a considerable numbers of adherents and, at the same time, it leaves room for further research, that is, its assumptions have to be valid and to allow further developments from its premises (Kuhn 10). As the author exemplifies, optics did not have a paradigm before Newton, and therefore, did not make any consistent progress until after the seventeenth century (13). The lack of unity within a field of research or of commitment to the same assumptions is clear evidence that no real progress has been made in a certain field.
In Popper’s view, a successful scientific corpus also involves the possibility of change and innovation. He thus gives the example of Karl Marx’s theory which was transformed by its adherents in an irrefutable system of investigation (Popper 38). This is a fatal mistake, since a theory that has unlimited scope of application cannot be valid. Kuhn emphasizes the progress of science both through consensus and through change. Essentially, the two philosopher’s theories meet at this point.
Thus, Kuhn makes a point of highlighting the fact that the notion of “paradigm” is much more apt to describe the consensus existing at a certain time within a scientific field, than would be the idea that research submits to and obeys the exact set of rules. The author speaks of the priority of paradigms over rules, and argues that there can be consensus or agreement with regard to a certain scientific matter, but the scientists might, nevertheless, give a different account of the particular details that lead to a certain solution (Kuhn 44). Popper also states that a theory should not recur to a “conventionalist twist” or a reinterpretation designed to make it infallible to error (Popper 37). He argues that, once it is proven false in some way, a theory should not be transformed in order to match the new findings. Also, the genuine test of a theory is not one that would look for general agreement but one that verifies it sustainability. The scientists should attempt to prove the theory false in order to verify its validity.
Similarly, for Kuhn there is agreement within the field of “normal science” with respect to the problem-solutions, and not to the specific rules used to achieve these solutions. This is why the most important requisite for scientific progress is the existence of paradigms or consensus within a certain field, and these paradigms are always oriented towards the solutions offered, and not necessarily towards a set of applicable rules.
In Kuhn’s theory, the discoveries essentially appear in the form if the acknowledgement of a certain anomaly in the structure of a paradigm. This can be proven with the example of the discovery of X-rays by Roentgen. This discovery was made precisely by noticing something which was wrong, or which did not fit the already known paradigm (Kuhn 57). The next important step in conceptualizing the structure of scientific revolutions is to account for paradigm change and inventions. Kuhn observed that new scientific theories or changes in paradigms occur when this awareness of anomaly generalizes and is acknowledged as a crisis in a certain scientific field. This is thus the structure of scientific revolutions in Kuhn’s view: the essential concept for their definition is the existence of paradigms or world-views that serve as a point of departure first for further development. Research can be added to the paradigms through discovery, without an actual paradigm shift, or the paradigm can be completely replaced through crisis. Scientific revolutions are sometimes so great that it can be said that with the advent of a paradigm shift, the world itself changes. However, as Kuhn sustains, the world does not actually change every time a paradigm shift occurs, although it can be said that the world does become a different place for the ones who perceive it from the point of view of a different paradigm (Kuhn 111). For Popper, a good theory is one that can also be refuted. Both philosophers emphasize scientific revolution as an essential aspect for the progress of science. Popper also believes that a good theory prohibits certain events in the empirical world, even though the theory is not complete. For both Kuhn and Popper therefore, a scientific theory is only valid when it prohibits certain phenomena but also allows for further development of the initial frame.
Kuhn, T. S. The Structure of Scientific Revolutions. Chicago: University of Chicago Press, 1996.
Popper, Karl. Conjectures and Refutations. London: Routledge, 1963.