 In philosophy of science, the metaphysical ideal of an absolute conception of the world has often been formulated within the “tradition of natural kinds” (Hacking 1991). Scientists do not invent arbitrary concepts but discover natural kinds that are constituted by objective discontinuities in nature. For example, consider biological species as paradigmatic natural kinds. Biologists do not distinguish between species along randomly selected criteria such as “animals born on a Tuesday” or “plants with beautiful flowers”. Instead, biological taxonomy progresses through empirical discoveries about the structure of the biological world that connects phylogenetic relations between populations with gene flows and reproductive patterns that affect their morphological properties, ethological profiles, and ecological roles. Species concepts reflect empirical insights into these structures and species are therefore natural kinds that are discovered in the world rather than the product of linguistic conventions.