Developments in genetic engineering may soon allow biologists to clone organisms from extinct species. The process, dubbed “de-extinction,” has been publicized as a means to bring extinct species back to life. For theorists and philosophers of biology, the process also suggests a thought experiment for the ongoing “species problem”: given a species concept, would a clone be classified in the extinct species? Previous analyses have answered this question in the context of specific de-extinction technologies or particular species concepts. The thought (...) experiment is given more comprehensive treatment here. Given the products of three de-extinction technologies, twenty-two species concepts are “tested” to see which are consistent with the idea that species may be resurrected. The ensuing discussion considers whether or not de-extinction is a conceptually coherent research program and, if so, whether or not its development may contribute to a resolution of the species problem. Ultimately, theorists must face a choice: they may revise their commitments to species concepts or they may recognize de-extinction as a means to make progress in the species problem. (shrink)