ABSTRACT
According to the cluster theory of human nature, it is important to recognize and maintain the distinction between being biologically human and having human nature. As a biological species, human beings are classified by biologists as the species, Homo sapiens in the Animal Kingdom, of the class Mammalia, the order Primate, the family Hominidae, and the genus Homo. The process of biological classification is one that is designed to capture the various relationships amongst different living organisms, and, as such, different systems of classification reflect the special interests and emphases of those who designed them. Recognizing and maintaining the distinction between biological human beings and human nature has some significant consequences that are likely to be met with a great deal of resistance on either religious or moral grounds. Many of the most philosophically challenging cases involve creatures that are part human, in some vague, traditional, commonly accepted sense, and part non-human.
