Claim. Rodney Stark’s sociological theory of religious growth: a religion grows in proportion to the number of attachments its members have to non-members — but only if the religion constitutes an open network (no in-group barriers that would prevent non-members from being welcomed as full participants).
Elaboration. Per expand-your-social-surface-go-native, Stark’s original formulation: “as movements grow, their social surface expands proportionately. That is, each new member expands the size of the network of attachments between the group and potential converts. However, this occurs only if the group constitutes an open network.”
The Christianity-in-Rome case Stark cites: early Christianity grew because (a) it allowed members to abrogate Jewish dietary laws and intermarry with non-Christians (open network); (b) it granted full membership and leadership positions to women, servants, and slaves (broader social surface); (c) Christians stayed in plague-infested cities to tend to non-Christian sick (extended care across the network); (d) all races and national origins shared the same communion (no in-group ethnic gate).
The diagnostic implications:
- A religion can have many members and still fail to grow if its network is closed — each member’s relationships are with other members rather than with non-members.
- Closed-network communities can be high-trust and high-commitment internally while shrinking in absolute terms.
- The “growth lever” is not mostly evangelism intensity per member but the openness of the network as a whole.
For UC application: 1970s UC growth occurred when the Creative Community Project presented an open network — converts entered through ordinary friendship networks. Later UC institutional patterns (heavy in-group time commitments, member-only marriages via Blessing, paranoid screening of outsiders) tend toward network closure. Stark’s theory predicts the growth consequence Hendricks documents.
See also. populist-church