Imre Lakatos

Imre Lakatos (1922-1974) was a Hungarian-born philosopher who studied demarcation criteria and theory choice in science.12 A protege of Karl Popper, Lakatos attempted to respond to problems posed by the work of Popper and Kuhn. His Methodology of Scientific Research Programmes (MSRP) offers a holistic approach to theory choice which extends beyond Popper's falsificationism, and instead assesses a particular research program as progressive or degenerative, depending on its overall record of predictive and explanatory successes and failures. Lakatos later entered into a correspondence with Paul Feyerabend, with the goal of addressing Feyerabend’s objections to the MSRP. He met an untimely death due to a heart attack at the age of 51. Some of Feyerabend’s objections remain open to this day.

Historical Context

Much of Lakatos’ work was a response to the problems of Popper’s falsificationism, which was expressed in a series of works published between 1935 and the early '70's. Lakatos rejected the idea that a false prediction was alone grounds for rejecting a theory. Most theories, he pointed out, are born in an “ocean of anomalies” and are therefore falsified from the moment of their inception. For example, Copernican heliocentric astronomy predicts that the stars should change in apparent position as the Earth revolves around the sun, but for three centuries after Copernicus proposed his theory, all attempts to detect this stellar parallax failed. Astronomers nevertheless accepted the theory on other grounds. The failure of Newtonian mechanics to account for the motions of the planet Mercury was known for many decades, during which the theory also wasn't rejected.1 A well known criticism of falsificationism, which Lakatos championed, was that the failure of a prediction could be due to a problem anywhere in the network of theories and auxiliary assumptions responsible for that prediction. Lakatos thus argued that Popper's theory was overly restrictive and inconsistent with much of scientific practice. In scientific practice, Lakatos observed that if a theory is the best available of its kind, it is typically allowed to undergo modifications to account for all data and not rejected.

Lakatos also responded to Thomas Kuhn’s Structure of Scientific Revolutions, published in 1962. He was troubled by Kuhn's incomprehensibility thesis, which asserts that theories with different taxonomies cannot be rationally compared. Lakatos accused Kuhn of depicting the process of scientific change as completely irrational. If there truly existed a problem of incommensurability in science, then there would be no method to demarcate between science and pseudoscience, and no way of measuring scientific progress.3 However, like Kuhn, Lakatos believed that any theory of science must make sense of the history of science.

CANT CORROBORATE THIS PART, OXYGEN IS NOT COMBUSTIBLE Lakatos held that theories employing different taxonomies could be compared provided they were rationally reconstructed in a common, modern language. For example, the phlogiston theory held that all combustible substances contained a hypothetical substance known as “phlogiston”. Today, chemists might identify combustible elements as hydrogen or oxygen. The example of phlogiston and/or hydrogen/oxygen serves to illustrate that a rejected theory in the history of science can be expressed in modern terms despite employing a different taxonomy. Lakatos accused Kuhn of depicting the process of scientific change as completely irrational. If there truly existed a problem of incommensurability in science, then there would be no method to demarcate between science and pseudoscience, and no way of measuring scientific progress.

Main Contributions to the Philosophy of Scientific Change

Lakatos on Theory Choice

Following the Quine-Duhem thesis, Lakatos recognized that scientific theories could not be appraised individually. Rather, all of the theoretical assumptions bearing on an experimental finding had to be assessed holistically, in terms of what Lakatos called a "research program". Within a research program, not all theoretical assumptions are treated equally. It contains a "hard core" of theoretical assumptions, which are its indispensable constituents. Any modification of the "hard core" results in the creation of a new research program. Adherents of a research program attempt to explain an increasingly wide range of relevant natural phenomena in terms of the core. In so doing, they create a "protective belt" of auxiliary propositions. This expansion of the range of applicability of the program constitutes its "positive heuristic". Scientists committed to a research program defend the "hard core" against change by using their ingenuity as needed to make alterations to the "protective belt" of auxiliary propositions to explain phenomena and avoid falsification of the core. This protection of the hard core is a research program's "negative heuristic". For example, the "hard core" of the Newtonian physics research program would consist of Newton's three laws of motion and Law of Universal Gravitation. The protective belt would include propositions such as "the Earth is an oblate spheroid" or "Neptune is 17 times more massive than Earth". In the nineteenth century, astronomers could not explain the movements of the planet Uranus using Newton's theory and known gravitational influences. Rather than modifying the theory itself, which would have obviated the Newtonian research program, they modified the protective belt by positing the existence of a new planet, whose Newtonian gravitational influence was affecting Uranus. The prediction was a stunning success, as the new planet, to be named Neptune, was discovered in 1846.23

Lakatos held that a research programme should be chosen for both its “explanatory power” and its “heuristic power”. That is to say that a theory is accepted for its ability to both explain past and present phenomena, as well as its ability to be applied to and posit the existence of future phenomena and anomalies. Given any evidence against a theory, if the theory possesses both greater heuristic and explanatory powers than its counterparts, its protective belt should be allowed to undergo modifications and avoid falsification. These modifications should be “progressive” and intended to save the research programme from degenerating. This, for Lakatos, represents the difference between falsification and rejection. A research programme is considered “progressive” if it can make predictions later confirmed by experiment, much in line with the Popperian notion of “novel predictions”. On the other hand, if a theory fails to offer such predictions and merely attempts to “save” itself from a disproving instance, it is considered “degenerative”. Lakatos established the following criteria for appraising modifications:

Progressive Modifications	Degenerative Modifications
Increase the empirical content of a research programme by making predictions and increasing its precision	Do not increase the empirical content, make predictions or increase the precision of a programme (ad hoc1)
Add excess empirical content which has been corroborated though experiments and observation	Introduce excess content, but fail to corroborate the excess content (ad hoc2)
Are in organic unity with the rest of the programme	Are not in organic unity with the rest of the programme (ad hoc3)


 The term organic unity is intended to mean that modifications should be contiguous with the rest of the programme. If the research programme is “natural selection”, a modification which adds the proposition “extra-terrestrial beings intervened with human evolution” would not be contiguous – not in organic unity – with the rest of the research programme and is therefore ad hoc₃.


Given any modification to a research programme’s protective belt, any research programme P1 would subsequently become P2. In this way we can track changes to research programme P from P1 to Pn and retrospectively ascertain if the modifications made have been progressive or degenerative. However, the degeneration of a research program doesn't necessitate its dismissal. Rather, given research programmes A and B, where programme A has been degenerating and programme B has been progressing, Lakatos suggests that the scientific community should invest most of its resources into A. The community should not invest all resources into A because there have been instances where a degenerative programme has become progressive, such as heliocentrism and atomism. According to Lakatos, working on a degenerative programme is not prohibited, but it is irrational given that it has ceased to bear fruit.

Lakatos on Demarcation Criteria

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.

Criticisms & New Directions

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.

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Authors

[Jacob MacKinnon], 2016

[Paul Patton], 2016