Moffett's outstanding paper includes an ambitious call for establishing a comparative study of societies, and it offers a theoretically convincing and thought-provoking definition of a human society as a starting point. I will begin by reflecting upon a crucial aspect of this definition, namely that societies are, in essence, identity groups. Then I will dig into two phenomena related to group identity, that is (i) the perceived temporal persistence of the group, and (ii) group schism.

By defining societies as identity groups, Moffett aligns with the social identity approach to group processes and intergroup relations (Reicher, Spears, & Haslam, Reference Reicher, Spears, Haslam, Wetherell and Mohanty2010). According to this approach, people mentally represent the social world in terms of relatively distinct human groups standing in power and status relationships with one another, and include themselves cognitively in some of these groups. Furthermore, a collection of individuals who see themselves as members of the same group may develop shared feelings of identification with the group. Group identification implies a subjective sense of belonging and attachment to the group (a sense of we-ness), and a commitment to embrace the group norms (values, beliefs, rituals, rules). Shared group identification facilitates cooperation, mutual support, and coordination of activities within the group (Ellemers, Reference Ellemers2012).

Importantly, social identity theorists link the process of shared identification to two important and interrelated group phenomena. One is concerned with the perceived temporal continuity of the group. The other regards the process of group fragmentation and schism. It is worthwhile discussing these two aspects of identity groups, which are only briefly mentioned by Moffett.

Moffett's definition of a society includes the fact of being capable to perpetuate its population for generations. However, there is an important subjective dimension to this, namely the fact that groups tend to be perceived by their members as entities that move through time (Sani et al., Reference Sani, Bowe, Herrera, Manna, Cossa, Miao and Zhou2007). There are two main aspects to perceived group continuity. First, members of a group see the cultural group norms as having been trans-generationally transmitted. Obviously, members are aware that the group is not monolithic and that aspects of the group have changed across history. However, the group is believed to possess some core, deeply ingrained cultural elements that remain essentially the same and are not eroded by the passage of time. Second, seeing a group as a temporally persistent entity typically implies the perception that different events and periods in the group's history are causally interconnected and form a coherent narrative. In other words, the group members see the main stages in the group history as parts of an unbroken stream. Importantly, a group that is perceived as having a high degree of persistence through time appears in some ways to be more like an entity, to have a higher degree of “reality,” than those with less or no persistence at all (Lickel et al., Reference Lickel, Hamilton, Wieczorkowska, Lewis, Sherman and Uhles2000). In turn, this enhances the perceived validity of the group norms and affords the group members with meaning, structure, identity, and positive self-regard (Sani, Bowe, & Herrera, Reference Sani and Reicher2008). For all these reasons, people tend to promote and protect the temporal continuity of the groups with which they identify, and feel threatened when thinking that this is in jeopardy. Furthermore, a perceived threat to the temporal endurance of the group is typically at the basis of group fragmentation and schism.

Social groups tend to be very dynamic wholes. Members of a group engage in a constant and incessant process of discussion and argumentation about the group norms. Complete uniformity is rarely achieved, and some differences are accepted as inevitable and therefore tolerated. However, there may be circumstances in which members of a subgroup consider a new norm that has become predominant in the group, or that has been officially ratified by the group establishment, as denying the group history and tradition, and therefore as breaking the temporal continuity of the group. Members holding these perceptions sense that the group has been transformed beyond recognition, which typically lead to dis-identification. These members may therefore decide to join a schismatic group that, in their own eyes, holds to the values that the parent group has lost. This allows these members to maintain a sense of group temporal continuity and identity integrity (Sani, Reference Sani2005). On the other hand, those group members who fully endorse a new norm obviously deny that the norm radically transforms the group identity. In fact, they typically claim that, not only is the new norm consistent with the group history and tradition, but it reinforces the group identity and makes it stronger vis-à-vis the new challenges imposed by larger contextual transformations.

As a concrete example of a schismatic process within an identity group, consider what happened within the Church of England when its synod voted in favour of the ordination of women to priesthood, in 1994. A substantial minority of members saw that vote as going against tradition and as transforming the Church of England into a completely different entity, that is, into a protestant sect. They felt betrayed, disillusioned, and detached, and as a result many of them left the Church of England to join another church. The supporters of the new legislation, however, claimed that women priesthood, far from changing the nature of the Church of England, made explicit some values, such as equality of men and women before God, which had always been implicit in the Church of England (Sani, Reference Sani2005; Sani & Reicher, Reference Sani, Bowe and Herrera1999).

To conclude, I think we should be grateful to Moffett for his exceptionally thorough and insightful theoretical proposal. I fully endorse Moffett's definition of human societies as first and foremost identity groups. A human aggregate cannot be a society if its members do not share a subjective feeling of identification with the aggregate itself. This definition has great heuristic value and may represent the beginning of a fruitful intellectual endeavour. I suggest that further developments of this theory pay close attention to the ways in which two important phenomena such as perceived group continuity and group schism manifest themselves in societies.