Occam's Razor and competing models of the universe

I was at the history of science museum at Oxford last Tuesday. These lovely armillary spheres of the solar system compare the Ptolemaic (left) and the Copernican (right) views. Made c 1700, "no serious astronomer would have doubted which was true." (stimulus for this post from James McGrath here.)

An orrery c 1800 2010-09-21