 As seen in the “pattern theories” discussed in  section 4.3,  approaches to biological and other scientific kinds are sometimes extended to social categories. Some participants in these debates, including Dupré (1995) and Hacking (2007), argue for a sweeping pluralism about scientific kinds: they contend that there are myriad kinds of kinds, and that it is an error to regard some kinds as more “natural” than others. Others argue for a more modest form of pluralism. Ereshefsky and Reydon (2015) argue that there are several distinct kinds of scientific kinds, including non-causal kinds, functional kinds, and heterostatic kinds. Along similar lines, many theorists of race argue for pluralism with respect to racial kinds: though contemporary race theorists deny “biological essentialism”, they argue that there are many ways racial kinds are constructed and used in contemporary societies (see  section 5.4).