But there is a
clear need to account for some of the less well-defined forms of religiousness also,
those that have no visible behavioural correlates and hence require methods capable
of eliciting any implicit, or incipient, religious mental states. In other words, the
nature of human populations considered by religious studies, on the one hand, and
modern psychology, on the other, is one of the more salient differences between the
two approaches to the study of religion. Thus psychology presupposes that the
whole human population (i.e., its representative samples) can be compared with respect
to any characteristic that can be observed or measured, and that only systematic
comparisons of this kind permit generalisations. In the case of religion as a psychological
variable, this implies that every living individual can be identified as
more or less capable of acquiring religion rather than being totally devoid of any of
its components. By contrast, the traditional disciplines of religious studies focus on
already selected groups (e.g., practicing Christians or Muslims) and dwell on the
specific cultural and social differences among them, thus arriving at findings of a
more limited relevance to the general population.