Abstract
The philosophical problem of the utility andmeaning of essences for chemistry cannot beresolved by Wittgenstein's principle thatessence cannot explain use, because use isdisplayed in a field of family resemblances.The transition of chemical taxonomy fromvernacular and mystical based terms to theorybased terms stabilized as a unified descriptivetaxonomy, removes chemical discourse from itsconnection with the vernacular. The transitioncan be tracked using the Lockean concepts ofreal and nominal essences, and the changingpriorities between them. Analyzing propertiesdispositionally, initiating a search forgroundings strengthens the case for a logicalasymmetry between descriptive and explanatorydiscourses. Taxonomy is now driven byexplanatory concepts, but not including thosefrom quantum chemistry.