What are groups?

Institutional Objects, Reductionism and Theories of Persistence

“…He holds that a set whose members are ordered pairs whose first coordinate is an instant of time and whose second coordinate is a set of concrete entities is co‐localized in space with the relevant concrete entities at the relevant instants (Ib., 257). However, Effingham's thesis seems fairly arbitrary, if not outright ad hoc (Ritchie , 167). Effingham appears to be defending it simply because he wants to identify institutional objects and groups with sets (rejecting extant alternatives) – no independent reasons for the thesis are given.…”

“…IV; cf. Ritchie , 260). So the second notion of a group appears to be self‐referential in Searle's sense .…”

“…Katherine Ritchie (, 268–271) also adopts a structuralist theory of (changeable) groups. But she holds that suitably interrelated individuals (i.e., not sets) “jointly realize” group‐structures consisting of nodes (places) and relations holding among nodes.…”

“…Uzquiano himself apparently rejects counterpart theory (, 147), but it is in any case unclear how the counterpart move is supposed to solve the prima facie difficulty (cf. Ritchie , 264). At present, I regard this issue as unsatisfactorily resolved.…”

The metaphysics of social kinds

“…However, on the assumption that individuals belong to social kinds on the basis of possessing certain properties, my discussion of social kinds is germane to the metaphysics of social properties. Finally, there are also social groups (see Effingham ; Epstein and ; Gilbert ; Hindriks ; and Ritchie and ; Tuomela ) and social structures (see Haslanger , 2015 and ).…”