A scientific revolution? The prion anomaly may challenge the central dogma of molecular biology.

Science, Thomas Kuhn argued in The Structure of Scientific Revolutions (1962), proceeds at two different paces. One is what he called “normal science”, which professionals, the general public, the press and politicians generally understand as “research firmly based upon one or more past achievements that some particular scientific community acknowledges for a time as supplying the foundation for its further practice.” This stepwise progression towards a better understanding of Nature, by building on established knowledge, has been described in a myriad of textbooks, dictionaries and scientific papers. However, Kuhn distinguishes this form of knowledge creation from so-called “puzzle-solving science”. The latter results from anomalies—experimental observations or other evidence—which do not fit into the widely accepted theoretical framework of how Nature functions. Puzzle-solving science, according to Kuhn, can therefore trigger a scientific revolution as scientists struggle to explain these anomalies and develop a novel basic theory to incorporate them into the existing body of knowledge. After an extended period of upheaval, in which followers of the new theory storm the bastions of accepted dogma, the old paradigm is gradually replaced. Perhaps the best example of such a paradigm shift in science is the Copernican revolution in cosmology: the move from a geocentric to the heliocentric view of our solar system. Curiously, although Aristarches had already laid the seeds of heliocentrism in the third century BC, it took another 18 centuries before Nicolaus Copernicus proposed that the Earth moves around the sun and not vice versa. Many anomalies, such as the orbit of Mars, were already known at that time, but the power of the Aristotelian dogmas, including the geocentric view of the universe, was too strong to be overcome easily. Truly speaking, however, the notion of a paradigm, as defined by Kuhn, does not have exactly the same meaning in cosmology, physics, chemistry, geology and biology.