 A survey of the different perspectives about biodiversity’s definition and its values suggests new challenges for a coherent philosophy of biodiversity. For example, there has been little work recognising and reconciling two contrasting perspectives. In the “variationist” perspective, biodiversity-as-variety, is justifiably “biological”, and is normatively relevant; it enters broader sustainability practice through trade-offs and synergies with other needs of society. In the “socio-ecological” perspective, “biodiversity” is too “biological”, with no normativity, and it fails us if it is not re-cast to capture as a term all of the things that concern society within the global change and sustainability agenda.