 Do the results of this section thus far imply that relational essentialism is correct? Consider two traditional requirements of essentialism highlighted by Okasha (2002). The membership requirement: the essence of a kind provides the necessary and sufficient conditions for membership in that kind. The explanatory requirement: citing a kind’s essence is central in explaining the properties typically associated with the members of that kind. Given these two requirements Okasha offers the following argument. Because certain relations are necessary and sufficient for membership in a species, such relations satisfy the membership requirement of essentialism. However, those relations do not satisfy the explanatory requirement. According to Okasha, relations such as genealogy and interbreeding fail to explain the traits typically found among the members of a species. Instead, we must cite the “genotype and its developmental environment” (2002, 204) to explain such traits. Despite failing to meet the explanatory requirement, Okasha thinks that certain relations are taxon essences. Okasha writes that there is no a priori reason to retain the explanatory requirement of essentialism and suggests that it should be dropped. With the explanatory requirement out of the way and the membership requirement satisfied, Okasha concludes that species have relational essences.