This paper analyzes the joint dynamics of religious beliefs and scienti
fic-economic development. It emphasizes in particular how this coevolution is shaped by (and feeds back on) political conflicts and coalition formation, along both religious and income lines. As part of our motivating evidence, we also uncover a new fact: in both international and cross-state U.S. data, there is a signi
ficant negative relationship between religiosity and innovativeness (patents per capita), even after controlling for the standard empirical determinants of the latter.
To shed light on the workings of the science-religion-politics nexus and its growth and distributional implications, the paper develops a model with three key features: (i) the recurrent arrival of scientifi
c discoveries which, if widely di¤used and implemented, generate productivity gains but sometimes also erode existing religious beliefs (a source of utility for some agents) by contradicting important aspects of the doctrine; (ii) a government that can allow such ideas and innovations to spread, or spend resources to censor them and impede their diffusion; (iii) a religious organization or sector (Church or churches) that can, at a cost, undertake an adaptation of the doctrine that renders it more compatible with the new knowledge.
The model leads to the emergence of three types of long-term outcomes. The fi
rst is a Secularization or Western-European regime, with declining religiosity, unimpeded scienti
fic progress, a passive Church and high levels of taxes and secular public spending. The second is a Theocratic regime with knowledge stagnation, extreme religiosity, a Church that makes no effort to adapt since its beliefs are protected by the state, and also high taxes but now used to subsidize the religious sector. In-between these two is a third, American regime, which generally (not always) succeeds in combining unimpeded scienti
fic progress and stable religiosity within a range where the state does not block new discoveries and the religious sector fi
nds it worthwhile to invest in doctrinal repair and adaptation. This regime features lower taxes than the other two, but with positive revenue or tax exemptions allocated to religious activities. We also show that, in this American regime, a rise in income inequality can lead the religious rich to form a religious-rightalliance with the religious poor and start blocking belief-eroding discoveries and ideas. Inequality can thus be harmful to knowledge and growth, by inducing obscurantist, anti-science attitudes and polices.