Christianization of the Roman Empire as diffusion of innovation

Christianization of the Roman Empire as diffusion of innovation looks at religious change in the Roman Empire's first three centuries through the lens of diffusion of innovations, a sociological theory popularized by Everett Rogers in 1962. Diffusion of innovation is a process of communication that takes place over time, among those within a social system, that explains how, why, and when new ideas (and technology) spread. In this theory, an innovation's success or failure is dependent upon the characteristics of the innovation itself, the adopters, what communication channels are used, time, and the social system in which it all happens.

In the empire's first three centuries, Roman society moved away from its established city based polytheism to adopt the religious innovation of monotheistic Christianity. Instead of explaining this through political and economic events, this approach focuses on the power of human social interactions as the drivers of societal change. This combines an understanding of Christian ideology and the utility of religion with analysis of social networks and their environment. While there are alternative explanations of Christianization of the Roman Empire, with differing levels of support from contemporary scholarship, this approach demonstrates that the cultural and religious change of the early Roman Empire can be understood as the cumulative result of multiple individual behaviors.^[1]

Christianity was adopted relatively quickly. Five characteristics of diffusion can explain the speed at which this happened: first, if an innovation is seen as having a relative advantage over what it is replacing, it will be adopted more quickly. Christianity's relative advantage over its various competitors can be found in its altruism, its acceptance of those without Roman status, and the specific type of network it formed. Second, its compatibility with the people, society, or culture it coexists with will impact the rate of adoption. Christianity was not highly compatible with Roman polytheism, but it was compatible with the Judaism found in the diaspora communities. Its complexity also matters, since simple is generally adopted faster, and Christian inclusivity made it relatively simple. The next characteristic, trialability, is about how well the innovation allows access to information about itself before someone becomes a full-fledged member, and the conversion process in early Christianity allowed a flexible period of trialability. The last characteristic affecting speed of adoption is observability, because it is more likely someone will convert if the individual believes they have seen results. This is represented by who it was who adopted it, and by the social changes, such as charity and martyrdom, that those different adopters helped create. These qualities interact and are judged as a whole. For example, an innovation might be extremely complex, reducing its likelihood to be adopted and diffused, but it might also be very highly compatible, giving it a larger advantage relative to current tools, so that in spite of specific problems, potential adopters adopt the innovation anyway.^[2]

Sociologist E. A. Judge explains Christianization through this sociological view as having occurred as a result of the powerful combination of new ideas Christianity offered, and the social impact of the church, which he says formed the central pivotal point for the religious conversion of Rome.^[3][4]