At the centre of nineteenth-century imperial authority sat the British Museum, which set the standard for discourse about natural history. This paper examines the meaning of those standards, exploring their important but little-understood role in ending the nineteenth-century species debate. The post-Reform Bill political assault on the authority of the British Museum is examined in the light of the ‘species problem’, and a surprising solution by John Edward Gray, keeper of the natural history collection, is seen as both a mediation and a closure of disputes over the meaning of species and the competence of naturalists. Gray's strategic solution – revealed in his copious notes on the parliamentary commissions investigating the affairs of the BM – embodied competence in institutional discourse and set the stage for the supposed ‘cynical’ definition of species later adopted in Darwin's Origin of Species, namely that species are merely what competent naturalists say they are.