Also, Horton is right and not so right in his historical claim. Yes, technically the Copernican system did not actually have more predictive power than the Ptolemaic system at first, at least not until Kepler et al. recorded considerably better observations than Copernicus and Barhe. However, initial objections to the Copernican system were often based on a bad epistemology (e.g., one that placed the Ancients as nearly overriding authorities) and an inane Aristotelian metaphysics (read the Vatican interviews/interrogations of Galileo, for instance, and see how they object). Further, much of, say, Galileo’s much does not have to do with “Theory-building” but with piecemeal experimental projects that turned out to be in conflict with the existing cosmology (e.g., in The Assayer the nature and orbit of comets). So Horton is right but doubly off track in these ways.