Drawing on the methods of the natural sciences as well as developing new techniques involving not only structured interviews but unstructured "participant-observation"—and drawing on the new theory of evolution through natural selection, they proposed the scientific study of a new object: "humankind", conceived of as a whole. Crucial to this study is the concept "culture", which anthropologists defined both as a universal capacity and propensity for social learning, thinking, and acting (which they see as a product of human evolution and something that distinguishes Homo sapiens—and perhaps all species of genus "Homo"—from other species), and as a particular adaptation to local conditions that takes the form of highly variable beliefs and practices. Thus, "culture" not only transcends the opposition between nature and nurture; it transcends and absorbs the peculiarly European distinction between politics, religion, kinship, and the economy as autonomous domains. Anthropology thus transcends the divisions between the natural sciences, social sciences, and humanities to explore the biological, linguistic, material, and symbolic dimensions of humankind in all forms.