 Finally, Penelope Maddy (1990) has also developed a sort of immanent realist view of mathematics. Concentrating mainly on set theory, Maddy maintains that sets of physical objects are located in space and time, right where their members are located. But Maddian sets cannot be identified with the physical matter that constitutes their members. On Maddy's view, corresponding to every physical object, there is a huge infinity of sets (e.g., the set containing the given object, the set containing that set, and so on) that are all distinct from one another but which all share the same matter and the same spatiotemporal location. Thus, on this view, there is more to a set than the physical stuff that makes up its members, and so Maddy might be better interpreted as endorsing a nonstandard version of platonism.