Preventing human-caused extinctions is a foundational aim of conservation. However, in addition to causing extinctions, humans have moved numerous species to new areas. A considerable percentage of these are threatened in their native ranges. Broadening our conservation ethos to include introduced species is contentious and requires critical thinking in empirical and normative dimensions to negotiate between conflicting conservation goals. Here, we present a series of questions to inspire critical thinking in the negotiation of these conflicts. Empirically, we suggest that conservationists should consider whether the effects of introduced species are due to their non-nativeness per se or are simply a consequence of the organism having a metabolism and taking up space. Importantly, this requires proper scientific comparison to the effects of similar native organisms – otherwise many claims of ‘harm’ are unfalsifiable and could be used to justify the eradication of any organism. We further propose questions to help conservationists sort facts from normative values, which often wear empirical clothes. Through empirical rigor, value transparency and critical justification of these values, we believe that twenty- first century conservation can become a future-facing and pluralistic discipline with a heightened ability to prevent extinctions in an increasingly unpredictable and novel biosphere.

Early human cultural dynamics underpin the Plio-Pleistocene archaeological record and impact how we understand some of our earliest identifiable behaviours. One major outstanding question is whether Early Stone Age material culture represents a single lineage of cultural information, or did we ever lose the knowledge required to make stone tools? No single approach satisfactorily addresses this problem, but to date, objective analyses of temporal data have been absent from the conversation. Here, using a comprehensive database of dated African Oldowan archaeological sites, we demonstrate that there are no temporal breaks large enough, on a relative basis, to infer a loss of stone-tool-making cultural information. Therefore, alongside previously published data, we infer a continuous record of early human stone tool production in Africa from c. 3.3 to 1.5 million years ago. Stone tool-associated behavioural adaptations and evolutionary selective pressures were, therefore, likely to have been ever present during this period.