Science is generally perceived as cumulative: researchers continually produce new knowledge which, like a brick wall, is added to existing knowledge to expand our understanding of the world. Thomas S. Kuhn’s epistemological classic The Structure of Scientific Revolutions  tempers this perception. History shows that science alternates between periods of normal research, when scientific work effectively aims to improve the scope and accuracy of existing knowledge, and periods of extraordinary research, also called scientific revolutions, when scientific practice is radically altered: conventional theories and methods are rejected, others are enshrined, and previously unexplored problems suddenly receive new attention. How and why do these revolutions occur? How are they resolved? Why are they so rare? Are they a factor of progress?
Through precise historical examples, often borrowed from physics, and foundational epistemological concepts, the author provides clear answers to these questions. Without calling into question the rigour of the scientific process, he highlights the importance of conformism in its execution: according to him, science is always based on the massive adherence of researchers to a paradigm, which they then constantly enrich and strengthen through the resolution of carefully chosen problems. Crises occur when anomalies, i.e. observations inconsistent with the existing paradigm, arise. They can be addressed either by adjusting the existing paradigm, as long as this is possible, or by rejecting it, when major anomalies are found. A new paradigm must then be established, i.e. new theories, applications and experimental methods to frame scientific practice. For Kuhn, this profound change makes the comparison between two successive paradigms immeasurable: the passage from one to the other does not necessarily constitute progress, in the sense that there would be a relationship of order between the two, but rather a radically different way of doing science, which makes it possible to provide an account of observations that were previously inexplicable.
These reflections allow us to step back from the scope and purpose of our research efforts: the topics we address, as well as the methods we use, are largely conditioned by – and serve – the paradigm in which they are embedded. They can also question the way knowledge is treated in economic models: often in a linear, continuous and one-dimensional way, without taking into account the fundamental ruptures caused by scientific revolutions.
Is orthodox economics on the verge of a revolution? This is a legitimate question, given that its scientific validity and its capacity to grasp climate change issues are now being called into question. Reading the work of Thomas S. Kuhn can help us to understand to what extent and how economic science can evolve to answer these questions.
Mohamed Bahlali, Ph.D. candidate Continuous-time optimal contracts, mean field games and environmental regulation.
 Kuhn, Thomas Samuel, The Structure of Scientific Revolutions, 1962, reviewed 1970. P 284.