 In discussions of the concept religion, this anti-essentialist approach is usually traced to Ludwig Wittgenstein (1953, posthumous). Wittgenstein argues that, in some cases, when one considers the variety of instances described with a given concept, one sees that among them there are multiple features that “crop up and disappear”, the result being “a complicated network of similarities overlapping and criss-crossing” (Wittgenstein 1953, §68).  The instances falling under some concepts lack a single defining property but instead have a family resemblance to each other in that each one resembles some of the others in different ways. All polythetic approaches reject the monothetic idea that a concept requires necessary and sufficient criteria. But unappreciated is the fact that polythetic approaches come in different kinds, operating with different logics. Here are three.