 In its strongest formulation, the tradition of natural kinds leads to the idea of one fundamental species ontology that reflects the structure of the biological world independently of any subjective human interests and values. In contrast, ontological pluralists have argued that there is not only one correct way of carving up the natural world and that different scientific interests and values lead to different but equally valid ontologies. Again, biological species can illustrate the argument. Indeed, biologists discover many details about the structure of the biological world, including an ever-increasing amount of knowledge about the ecological, ethological, genetic, morphological, reproductive, and phylogenetic properties of organisms. However, this knowledge does not culminate into one uncontested and objective division of the biological world. Biologists do not have access to one objective “view from nowhere” but their taxonomies reflect diverging perspectives that are shaped by diverse (e.g., ecological, ethological, evolutionary) research interests and attention to heterogenous (e.g., bacteria, dinosaurs, mosses) organisms. Given this diversity of research questions and reference organisms, biologists pay attention to different properties of organisms and operationalize species in different ways. The reality of biological research practices does not seem to support the idea of convergence towards one absolute scientific conception of the biological world.