# Statistical modeling of membership in organized Western religion

A recent research paper, “A mathematical model of social group competition with application to the growth of religious non-affiliation”, co-authored by Daniel M. Abrams, Harley A. Yaple, and Richard J. Weiner, applies the tools of statistical mechanics and non-linear dynamics to membership in religious organizations. Unfortunately, based on this mathematical analysis, the authors jump to unwarranted broad conclusions:

People claiming no religious affiliation constitute the fastest growing religious minority in many countries throughout the world. Americans without religious affiliation comprise the only religious group growing in all 50 states; in 2008 those claiming no religion rose to 15 percent nationwide, with a maximum in Vermont at 34 percent. In the Netherlands nearly half the population is religiously unaffiliated. Here we use a minimal model of competition for members between social groups to explain historical census data on the growth of religious non-affiliation in 85 regions around the world. According to the model, a single parameter quantifying the perceived utility of adhering to a religion determines whether the unaffiliated group will grow in a society. The model predicts that for societies in which the perceived utility of not adhering is greater than the utility of adhering, religion will be driven toward extinction. [p.1]

The mathematical analysis appears to be sound — I’m not a mathematician, and not competent to judge this myself, though it seems consistent with what little I know about mathematical modeling of non-linear systems. But the model really only applies to reported membership in traditional Western religious groups. In religion will be “driven toward extinction”, the authors are assuming that membership in a congregation or organized religious social group is equivalent to “doing religion” or “being religious.” While this may be true for certain cultural contexts, e.g., where contemporary Western Christianity is assumed to be normative, it does not hold true in other cultural contexts. For example, in Japan individuals are often not “affiliated” with, or “adherents” of Buddhist temples or groups, yet when a family member dies many people will still turn to a local Buddhist temple for funeral rituals; this type of religion does not equate being religious with group or institutional affiliation or adherence.

Furthermore, in Western society, scholars of new religious movements have argued that some forms of cultural life ordinarily understood as non-religious look so much like religion that they can be usefully understood as new religions or alternative spiritualities. One reference book on new religious movements, New Religions: A Guide [ed. Christopher Partridge, Oxford, 2004], includes entries on the human potential movement, celebrity-centric spirituality, transpersonal psychologies, feminist and ecofeminist spiritualities, raves, sports, etc. Christopher Partridge states that while there is undoubtedly truth in saying that Western societies are becoming increasingly secularized, insofar as “traditional religion is on the decline in the West, it is not the whole picture. Throughout the West there has been a subtle growth of new and alternative forms of spirituality, which seem particularly suited to contemporary Western culture.” [p. 359]

A key concept here is “implicit religion” (which used to be called “secular religion”), which is related to Robert Bellah’s “civil religion,” and Thomas Luckman’s “invisible religion”; religious behaviors that exist outside of the boundaries of traditional Western definitions of religion. Indeed, some scholars of religion have made arguments that religion itself is a flawed concept of Western thought which accepts Western culture as normative. Additionally, definitions of religion have changed over time even in Western culture; some early Christians called what they did disciplina rather than religio.

Thus, while participation in traditional organized religion is dropping in Western cultures, one cannot conclude, as Abrams, Yaple, and Weiner do, that religion will become extinct in the West, except for a very narrow definition of religion. It would be more accurate to conclude that in some places organized traditional Western religious groups are waning in numbers and social influence, while Western religion takes on new forms as Western culture changes and evolves. But claiming the “extinction” of religion is imminent in certain countries, as the authors do, shows a poor understanding of what constitutes religion.

Sigh. This is what happens when physicists try to do religious studies and sociology without learning the basics of the latter two fields: they mix good mathematical models with poor understanding of what it is they’re actually modeling. It’s as awkward as watching most theologians trying to talk about the Heisenberg Uncertainty Principle.

## 4 thoughts on “Statistical modeling of membership in organized Western religion”

1. I am trained as both a mathematician and economist, and yes, this is what you get when the mathematical sciences jump into the social sciences (of which there is too much going on in general.) A mathematical critique of their model – they use a constant for the utility/probability of shifting between one group (affiliated) to the other group (non-affiliated.) This is heroic assumption – that the likelihood of changing stays the same for all time. It ignores exogenous shifts in taste/desire; and it assumes no diminishing/feedback (endogenous) changes. All that on top of your points about what it is they are actually measuring.

This kind of model works more or less OK for epidemiolgy, like the steady state percentage of people with the sickle-cell in a malarial environment (trade-off of sickle-cell mortality versus survivial conferred by the gene) – the object being studied has fixed properties over the longer run. But it’s kind of iffy when it involves human preferences and changing nature of the things being preferred. They should at least have had a modern social economist on board.

2. Dan says:

Tom @ 1 — Thanks for your comment.

I read Jay Forrester’s Urban Dynamics years ago, and thought it was quite brilliant (it helped that I could understand more or less what he was doing with his Fortran models). But as I recall, Forrester was pretty up front about the limitations of his model, besides which his real point was to demonstrate the non-linear nature of urban systems: what he aimed to show was that reality is more complex than the usual simple cause-and-effect relationships that our human brains feel most comfortable with. But what I hear you saying is that Abrams, Yaple, and Weiner are actually using non-linear analytical tools in a way that makes reality seem simpler than it is, and more comfortable to the human brain. I guess this just goes to show how it is possible to use complex analytical tools to make complex reality seem too simple.

3. I just read about this study this morning, and though I haven’t yet had a chance to read the paper itself. Needless to say, I’m skeptical of both their methods and results. Coming from a physics background, I understand the idea of using models to read, understand, and generate data: I used to study statistical thermodynamics. But I also an extensive background in religion: I’ve written extensively on pluralism and secularism/atheism and the idea of theories of models in religion. I believe, when it comes to models, Jonathan Z. Smith’s essay “Map is Not Territory” is the best possible reference. He’s referring primarily to description of religions through anthropological models, but you can extend his theories to sociological trends. His message distills to this: Be wary of whether you are creating maps or using maps, because there are “models of” and “models for” and they cannot always be used interchangeably.

I couldn’t agree more with your last paragraph: “This is what happens when physicists try to do religious studies and sociology without learning the basics of the latter two fields: they mix good mathematical models with poor understanding of what it is they’re actually modeling. It’s as awkward as watching most theologians trying to talk about the Heisenberg Uncertainty Principle.” These mathematicians/physicists are looking at numbers and trends within the numbers. They have no notion or sense of the social trends within the religions. They say they are confident that the spread of Islam in Europe won’t affect the overall drive towards the extinction of organized religion. Needless to say, when it comes to modeling behaviors, physicists should stick to particles. (And theologians should avoid Heisenberg.)

Your commentary on the study is spot on, in my opinion.