Prior to the advent of evolutionary theory the Natural System was generally conceived as based on "distinctions of kind, not consisting in a given number of definite properties" (J.S. Mill). It was considered final and unique, to be arrived at by more than one approach. Evolutionary theory has shifted emphasis to different characters, yet explicitly or implicitly the belief in a final natural system in biology persists in many textbooks and taints research. Allegedly natural systems are shown to be fundamentally (...) arbitrary and artificial, dependent on numerous value judgments and intrinsically conflicting to varying degrees. Because of this and because it has turned into a bar to clear thinking, the adjective "natural" should be abolished. (shrink)