“New opinions are always suspected, and usually opposed, without any other reason but because they are not already common.”

-John Locke, 1690

Revolutions are usually considered bloody affairs. In science, this is rarely the case, as those white lab coats do stain easily. It would seem crazy to think of science as having a revolutionary history, a sort of dialectic that puts one theory in the red corner and another in the blue. Science is normally thought to involve thousands of tedious hours of hard work gradually adding to our understanding of the world.

Yet we have already encountered the ‘Black Swan’ – that piece of evidence that refutes a hypothesis, and we have struggled with how to proceed from there. Standard practice would be to reject the hypothesis, and continue further research, and in fact, that is how the majority of science is conducted.

What happens when someone develops a new theory though, one that fully explains all the existing observations, but in a novel way? Sometimes, this shakes the foundations of science – new science can only progress in light of this new idea.

In 1543, Nicolaus Copernicus died in the same year his work De revolutionibus orbium coelestiumOn the Revolutions of the Celestial Sphereswas published (it’s possible he got to see a copy on his death bed). In this, he proposed that the Earth and other planets revolved around the Sun: a quite heretical idea for its day. Prior to this, increasingly complex models for a geocentric (Earth at the center) explanation of the movement of the planets and the Sun had been accepted.

It would take some 200 years for this idea to be fully concluded by Isaac Newton, but Johannes Kepler and Galileo Galilei largely resolved Copernicus’ ideas very early in the 17th Century.

It could be argued that a century or so of observing and theorising does not qualify as a ‘revolution’. However, it is clear that scientists post-Copernicus were transfixed with his new idea, and it would soon become foundational to astronomy.

Thomas Kuhn, in The Structure of Scientific Revolutions proposed that science goes through stages. Normal science is highly productive, but, curiously, results that don’t conform to accepted theory (the Paradigm) are often challenged as error by the researcher. But these anomalous results build up and the science reaches a crisis point at which radical new theories explain the data better – revolutionary science – and thus a new Paradigm is accepted. A ‘Paradigm Shift’ has occurred.

Paradigm shifts can be observed in the histories of many sciences, for instance in astronomy (as above), biology (evolution by natural selection) and geology (plate tectonics).

Kuhn further argued that the new paradigm was so different that the old paradigm could not be understood through the lens of the new. This is a subtle philosophical point that has been hotly debated (critics tend to see it as a form of radical postmodernism or cultural relativism) however it seems clear that there is a revolutionary aspect to the history of science. The shifts in thought that followed such work as that of Copernicus or Darwin for instance make this much obvious.

So, occasionally, a radical idea shifts the foundations of science, and it is never the same again. This revolution occurs despite scientists working within their strict rules of hypothesis and evidence, and despite their nerdy lab coats. Just how strict are scientists with their rules? Science is not an authoritarian state after all. Thus we must meet Paul Feyerabend: next time…

This article first appeared in print in my column in Woroni, the student newspaper of The Australian National University, 1 August 2013.