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Epicycle science - September 05, 2008

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.

Posted by Daniel Cressey on September 05, 2008
Categories: Neat technologies | | Comments (1) | TrackBacks (0)

Comments

Hello, first of all I want to thank you for the citation. Nevertheless, to be fair I must say that the demonstration belongs to Hanson (1960) and the animation to Christián Carman and Ramiro Serra. The paper you mention, written by Christian Carman and myself (2008), is about the refutability of natural selection. We compare this theory with a version of the Ptolemaic system of epicycles and deferents in order to show that the theory of natural selection is not trivial in a sense in which the Ptolemaic theory is. Now, Christian Carman has changed his mind and he believes that Ptolemy’s theory is not trivial at all.
Sincerely,
Santiago Ginnobili

- Ginnobili and Carman, (2008) “Epiciclos, deferentes y adaptaciones” in Roberto de Andrade Martins et al. (eds.) Filosofia e história da ciência no Cone Sul. Seleção de trabalhos do 5º Encontro. Campinas: Associação de Filosofia e História da Ciência do Cone Sul (AFHIC), 2008, ISBN: 978-1-4357-1530-1, pp. 399-408.
- Hanson (1960), “The Mathematical Power of Epicyclical Astronomy”, Isis 51, pp. 150-158

Posted by: Santiago Ginnobili | September 17, 2008 01:32 AM

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