Obviously Kepler's astronomical model is superior and that line might have been rhetorical flourish but the Ptolemaic, Copernican and Tychonic models were by no means "rough approximations" that don't "work very well". Epicycles worked very well which is part of why it took so long to get rid of them- the deviations of theory from actual planetary paths were so small that they were only detectable over long periods of time or unprecedented observational accuracy (before Brahe).

(I don't understand the grandparent's point either and agree that mathematical reduction to set theory is a different sort of thing from physical reduction to quantum field theory-- just pointing this one thing out.)