 Species pluralists respond to this objection by suggesting criteria for judging the legitimacy of a proposed species concept (Dupré 1993, Ereshefsky 2001). Such criteria can be used to determine which species concepts should be accepted into the plurality of legitimate species concepts. Candidate criteria are the epistemic virtues that scientists typically use for determining the scientific worthiness of a theory. For example, in judging a species concept, one might ask if the theoretical assumptions of a concept are empirically testable. The Biological Species Concept relies on the assumption that interbreeding causes the existence of stable lineages. It also assumes that organisms that cannot interbreed do not form stable lineages. Whether interbreeding and only interbreeding causes the existence of stable lineages is empirically testable. So the Biological Species Concept has the virtue of empirical sensitivity. Other criteria for judging species concepts include intertheoretic coherence and internal consistency. Pluralists can provide criteria for discerning which concepts should be accepted as legitimate. Thus the ‘anything goes’ objection can be answered.