Passage A:

Historians of science have argued that the Copernican revolution succeeded not because heliocentric models made substantially more accurate predictions than the Ptolemaic system they replaced — for decades after Copernicus, they largely did not — but because heliocentrism offered greater theoretical simplicity and coherence, eliminating the need for the ad hoc equants and epicycles that Ptolemaic astronomers had accumulated to save the appearances. On this view, scientific theory choice is frequently driven by aesthetic and explanatory virtues that outrun, and sometimes precede, decisive empirical confirmation.

Passage B:

The simplicity narrative undersells how much Copernicus's own system still relied on epicycles to match observed planetary motion, since uniform circular motion around a stationary sun could not, by itself, reproduce the irregularities astronomers had long recorded. Copernicus's heliocentrism was simpler only in certain qualitative respects — explaining retrograde motion and the ordering of the planets without additional assumption — while remaining comparably complex in its detailed predictive machinery. The revolution's real work was done later, by Kepler's elliptical orbits and Galileo's telescopic observations, which did deliver the predictive and observational advances the simplicity account wrongly credits to the original heliocentric proposal itself.