ABSTRACT
Scientists divide the particulars that they study into kinds and classes. Chemists classify particular pieces of gold, as members of the class gold. We cluster things together and find this useful for the purposes of prediction and explanation. For example, we think we can study one piece of gold and learn things about other pieces of gold. Debates about classification in philosophy have traditionally focused on the delineation of natural kinds of substances. More particularly, we ask whether these natural kinds reflect real natural divisions in nature or whether alternatively they merely reflect the theoretical interests of the scientists that use them. The discussion has more recently invoked a more generous notion of natural kind, going broader than substances to consider whether we can have natural kinds of processes, relations, and/or property clusters (Ellis, 2001).
