Via Steinn Sigurðsson’s Dynamics of Cats blog this rather excellent piece of Friday-fodder has surfaced. Philosopher of science Santiago Ginnobili and his colleague Christián Carlos Carman have constructed this awesome demonstration of the power of epicycles.

For those of you not au fait with ancient cosmology, epicycles are a way of explaining the motions of planets using only perfect circles. Assuming planets moved in perfect circles did not explain what was seen in the sky, so astronomers added secondary and tertiary circles, smaller and smaller, to try and create patterns which agreed with observation.

In theory any curve can be constructed using this method, if you’re prepared to add enough circles.

This exercise appears to be tied up with ideas of refutability and falsification in science, but to be honest my language skills aren’t up to translating philosophy of science papers in other tongues. Just enjoy the video for now.