For the past 500 years, to varying degrees, the processes of religious
secularization have been occurring in what today are the wealthy, highly
educated, industrialized nations of the world. They are causing organized
religion, as a social institution, to go from being a very important influence on
the lives of people and the nations in which they live to being a smaller
influence, or almost no influence at all. Various disciplines from theology to
psychology to sociology have tried to explain secularization, each discipline
contributing something unique. One discipline that has not contributed has
been biology. From a biological perspective, based on observation and
reasoning, at least one of the ultimate functions of the physical forms
associated with religion appear to be that of in-group marker for a breeding
population, which, as will be shown, is how all religions start. Religions
structure larger human populations into smaller “clusters” that are separate ingroup
breeding populations. The clustering into smaller in-group breeding
populations prevents the spread of contagious diseases and creates inter-group
competition and intra-group cooperation, both of which have contributed to
human eusociality, a very rare type of social organization that will be
explained. As the physical forms of religion are losing this in-group-marker
function of clustering populations with modernity, a general biological
principle comes into play, which is “form follows function, and as function
wanes, so does form.” When applied to religion, “form” means the physical
components by which all religions are built. The specific meaning of
“physical,” as used here, will be explained in the article. This biological
perspective, which is counter-intuitive and can generate testable hypotheses,
should complement, not compete, with perspectives from other disciplines.
Physical forms in biology can and often do have more than one function, so the
same form with a biological function can also have psychological and
theological functions. The physical forms of religion are its objects of natural
(genetic and cultural) selection. As socio-economic modernity spreads through
the world, the evolutionary biological trajectory suggests that religion, as a
social institution, will eventually become extinct.