ABSTRACT
To apply a taxonomic criterion is to identify classes newly introduced or modified. Consider Copernicus’ achievement, an achievement that Kuhn himself labeled “revolutionary.” What are the relevant classes? Kuhn suggested that Copernicus introduced a new taxonomic category, the category “satellite.” In Ptolemy’s taxonomy of astronomical bodies there are just “stars” and “planets.” Copernicus augmented this taxonomy by creating a new category for the Moon. On this reading Copernicus did introduce a holistic taxonomic change.
