Changes

The demarcation between “progressive” and “degenerative” research programmes also serves to demarcate between science and pseudoscience. A scientific theory should not only explain past and present phenomena; it should also have the ability to be applied to and posit the existence of future phenomena. For example, proving that an object falls in an experiment does not make the Newtonian research programme scientific. However, the Newtonian research programme predicted that comets move in either hyperbolas, parabolas or ellipses (contrary to the contemporary theory that they move in straights lines). Using this hypothesis, Edmond Halley successfully predicted the return of Halley’s comet to the minute. Such predictions affirm that the Newtonian research programme was progressive and, therefore, scientific. On the other hand, a research programme such as astrology, which merely provides post hoc explanations and is subject to ''ad hoc'' modifications, is considered pseudoscientific.

|Criticism=Paul Feyerabend pointed out that there exists a serious problem in how one can justify working on a degenerating programme. Lakatos’ response to Feyerabend's criticism was ambiguous. While it is irrational to work on a degenerating programme, Lakatos held that it was not prohibited. Just because a research programme is degenerating does not mean that it should be rejected. Feyerabend's objection, however, remains open because Lakatos failed to provide anything more than stipulation.

Feyerabend also argued that a problem exists with the notion of a time limit. If a research programme has been degenerating for some time, how do we know when to abandon it? Heliocentrism and atomism had degenerated for well over a millennium before being reinvigorated and subsequently accepted. On the other hand, fields such as homeopathy or psychoanalysis, which are nascent in comparison to the aforementioned theories, are easily ascribed the title of pseudoscience. Lakatos’ response was that there is no discernable time limit; but once again, he failed to address the actual problem.

|Related Topics=Mechanism of Scientific Change,