Evolution or Revolution?

Art by Inez Januszczak

In 1927, twenty-nine of the world’s leading physicists gathered in Solvay, Brussels for a conference on “Electrons and Photons.” Seventeen attendees went on to become Nobel Prize winners. Although invitations were only extended to those considered leaders in their fields, it is striking that the enthusiasts of such a confined scientific discipline received such repeated honour at science’s most prestigious awards. It may not seem so surprising however, given some of their pivotal discoveries.

Twenty-seven years earlier in 1894 Albert Michelson, a distinguished physicist himself, bravely asserted, “The more important fundamental laws and facts of physical science have all been discovered”. Nine years later, in his famous Annus Mirabilis papers, Einstein revealed the “Principle of Relativity,” “the equivalence of mass and energy,” and described light as made of “discrete quanta.” What followed this was a rapid period of profound and pervasive scientific upheaval and discovery that saw many scientists celebrated for their contributions. The pace of scientific discoveries such as these, led philosopher’s to begin wondering how the nature of scientific discoveries is best described.

Karl Popper was one such philosopher who developed his own theory on scientific discovery. He was heavily influenced by Einstein’s papers, whose theories he felt had a real audacity which the works of his philosophical contemporaries lacked; Einstein’s claims had the potential to be refuted with simple observations. This inspired Popper to produce his theory of scientific discovery (see Bang! Michaelmas Term 2010, p7). The idea, which proved extremely influential, was that scientists contributed refined theories which were tested by experiment and then either corroborated and integrated into the scientific model, or falsified and discarded. Through this distillation, a more accurate theory of the world crystallised.

However, such a steady, accumulative model of progress does not seem to tally with the quite extraordinary, and surprisingly rapid, advancements made by small groups, such as those at Solvay in 1927 . Thomas Kuhn realised this and so, in 1962, published his seminal work The Structure of Scientific Revolutions, which offered a starkly contrasting alternative to the Popperian view. Kuhn believed that by treating Popper’s philosophy as a realistic pattern of scientific development, people were overlooking what could be learned from the history of scientific progress.

Kuhn had noticed some problems with Popper’s theory. First, since all theories are inherently imperfect, they would be falsified. This would leave Popperian adherents with no theories to believe in. On the other hand, if the Popperians clung to a theory until a sufficient ‘degree of falsification’ was provided, Popper’s absolute analysis would be reduced to a probabilistic judgement.

Kuhn’s suggestion was that ‘normal science’ was instead conducted within a framework or ‘paradigm’ of assumed facts which provided a structure of common beliefs and language. This common structure is what allows scientists to collaborate without becoming bogged down by the imperfections of the current theory, or their personal scientific views, allowing them to collectively pursue research within the framework.

However, Kuhn recognised that the intrinsic rigidity of a paradigm would lead to its inevitable failure. An accretion of experimental evidence calling the assumptions of a paradigm into question would cause the community to enter a tumultuous and unguided ‘crisis’ period. In this time, new theories would be tried and old ones revisited in desperate attempts to search for some kind of understanding. If unresolved, this crisis would eventually culminate in a shift to a new paradigm; leaving the old paradigm to die, for, “to desert the paradigm is to cease practising the science it defines.”

In the 1840s the discovery of peculiar motion in the orbit of Uranus led Urbain Le Verrirer to suspect a fault in the accepted theory of the solar system. Rather than question the paradigm of Newtonian gravity, Le Verrier suggested that an additional trans-Uranian planet was causing the perturbed trajectory, an idea that was validated with the discovery of Neptune. An additional planet was discovered, and faith in the Newtonian paradigm was strengthened by the success. Turning his attention to similar misbehaviours in the motion of Mercury, Le Verrier postulated an intra-Mercurial planet, even naming it Vulcan. No such planet was ever found. Increasingly concerned by the unexplained data, scientists attempted other explanations including an aspherical sun and some awkward corrections to Newton’s theory. Ultimately though, the Newtonian paradigm had been stretched beyond its limits and the ‘crisis’ eventually precipitated the shift to a new paradigm, that of Einsteinian Relativity.
Kuhn’s hypothesis provided an appealing explanation for these “scientific revolutions,” but was at odds with the Popperian view. Kuhn maintained that the process of a paradigm shift, for example, from Newtonian to Einsteinian physics, is not achieved by a gradual merging process. This inter-paradigm rift proposed by Kuhn emphasised that the two philosophies of Kuhn and Popper were so fundamentally different that they could not be reconciled.

These clashes contributed heavily to the somewhat rocky reception of Kuhn’s work. The consequence seemed to be that it is impossible to judge which of the two paradigms is better. But the shock to the scientific community went deeper. During the 17th Century, great minds such as Isaac Newton started to replace the then widely accepted ideas of the Ancient Greeks with radical new scientific views. Kuhn’s theory saw this as a scientific revolution, or more specifically The Scientific Revolution—the period which marked the transition from primitive to mature science. Many scientists and philosophers did not warm to the possibility that such discontinuous paradigm shifts could be a feature of progress in mature sciences, and maintained that intellectual development was a process of refinement. By daring to contradict this, Kuhn was perceived to be dragging science back to the dark ages, claiming that the scientific endeavour had not only not progressed towards the goal of a complete understanding, but that since paradigms will always fail, even the notion of such a goal was preposterous.

Thus, without attempting to undermine the reputations of those twenty nine at Solvay in 1927, they are, in terms of Kuhnian philosophy, differentiated from leading scientists of any era mostly by the fact they were working in a time of scientific “crisis” when discoveries were there for the taking.
Criticism of Kuhn’s stance claimed that he had swung too far in opposition to Popper in claiming that Popperian refinement was completely invalid. Duly, with age, Kuhn softened his stance, conceding that progress may not require a total breakdown of scientific framework, and later even attempted to reconcile his views with a Darwinian evolutionary tree model of scientific thought. The reactionary nature of Kuhn’s initial stance can easily be understood as the product of the context of his work. Kuhn was fighting to challenge what he perceived as a misguided understanding; the establishment defended itself as vigorously as Kuhn claimed it would as he instigated his very own paradigm shift.

Kuhn’s The Structure of Scientific Revolutions is now one of the most cited academic books of all time, and his contribution to scientific philosophy unquestioned. As for the scientific community, notable for failing to heed the importance of historical study, it learned some valuable lessons; in Kuhn’s own words, “history, if viewed as a repository for more than anecdote or chronology, could provide a decisive transformation in the image of science by which we are now possessed.”

Philip Crowley is a 3rd year undergraduate studying Physics at St. Hugh’s College.