 Some have claimed that, lacking an essence, polythetic approaches to religion make the concept so vague that it becomes useless (e.g., Fitzgerald 2000: 72–3; Martin 2009: 167). Given the focused example of a “bounded” approach in the previous paragraph and the widespread adoption of polythetic approaches in the biological sciences, this seems clearly false. However, it is true that one must pay attention to the parameters at work in a polythetic approach. Using a properties set with only five elements produces a very focused class, but the properties set is simply a list of similarities among at least two of the members of a class, and since the class of religions might have hundreds of members, one could easily create a properties set that is much bigger. Not long after Wittgenstein’s death, a “bounded” polythetic approach was applied to the concept religion by William Alston who identified nine religion-making  characteristics.[12]  Southwold (1978) has twelve; Rem Edwards (1972) has fourteen and leaves room for more. But there is no reason why one might not work with a properties set for religion with dozens or even hundreds of shared properties. Half a century ago, Rodney Needham (1975: 361) mentions a computer program that sorted 1500 different bacterial strains according to 200 different properties. As J. Z. Smith (1982: ch. 1) argues, treating the concept religion in this way can lead to surprising discoveries of patterns within the class and the co-appearance of properties that can lead to explanatory theories. The second key parameter for a polythetic approach is the threshold number. Alston does not stipulate the number of characteristics a member of the class has to have, saying simply, “When enough of these characteristics are present to a sufficient degree, we have a religion” (1967: 142). Needham (1975) discusses the sensible idea that each member has a majority of the properties, but this is not a requirement of polythetic approaches. The critics are right that as one increases the size of the properties set and decreases the threshold number, the resulting category becomes more and more diffuse. This can produce a class that is so sprawling that it is difficult to use for empirical study.