Marion Godman

Natural kinds is a widely used and pivotal concept in philosophy – the idea being that the classifications and taxonomies employed by science correspond to the real kinds in nature. Natural kinds are often opposed to the idea of kinds in the human and social sciences, which are typically seen as social constructions, characterised by changing norms and resisting scientific reduction. Yet human beings are also a subject of scientific study.Does this mean humans fall into corresponding kinds of their own? In The Epistemology and Morality of Human Kinds Marion Godman defends the idea of human kinds. She first examines the scientific use and nature of human kinds, considering the arguments of key philosophers whose work bears upon human kinds, such as Ian Hacking, John Searle, Richard Boyd and Ruth Millikan. Using the examples of gender, ethnic minorities and Buddhism she then argues that human kinds are a result of ongoing historical reproduction, chiefly due to pre-existing cultural models and social learning. Her novel argument shifts the focus away from the reductionism characteristic of research about human kinds. Instead, she argues that they are “multiply projectable” and deserving of scientific study not in spite of, but because of their role in explaining our identity, injustice and the emergence of group rights.

Natural kinds, real kinds, or, following J.S Mill simply, Kinds, are thought to be an important asset for scientific realists in the non-fundamental (or “special”) sciences. Essential natures are less in vogue. I show that the realist would do well to couple her Kinds with essential natures in order to strengthen their epistemic and ontological credentials. I argue that these essential natures need not however be intrinsic to the Kind’s members; they may be historical. I concentrate on assessing the merits of historical essential natures in a paradigm case of Kinds in the non-fundamental sciences: species. I specify two basic jobs for essential natures: 1) offering individuation criteria, and 2) providing a causal explanation of the Kind’s multiple projectable properties. I argue that at least in the case of species historical essences are fit for both tasks. The principled resistance to Kinds with historical essences should also be cleared.

This paper aims to build a bridge between two areas of philosophical research, the structure of kinds and metaphysical modality. Our central thesis is that kinds typically involve super-explanatory properties, and that these properties are therefore metaphysically essential to natural kinds. Philosophers of science who work on kinds tend to emphasize their complexity, and are generally resistant to any suggestion that they have “essences”. The complexities are real enough, but they should not be allowed to obscure the way that kinds are typically unified by certain core properties. We shall show how this unifying role offers a natural account of why certain properties are metaphysically essential to kinds.