This thesis is on Cognitive Science of Religion (CSR) and its relevance for the rationality of religious beliefs. An epistemical model for rationality is developed according to which: a person (or group of persons) is rational to hold a certain belief a) if this belief can be assumed to have been generated by one or more reliable cognitive mechanisms, b) applies whether or not she is aware of what these mechanisms are, but c) only as long as it does not exist or arise some reasons (defeaters) to question the belief; if they occur, she must d) reflect on it and find other reasons or grounds to hold the belief in question.      Two different positions are examined, namely: 1) negative relevance: the findings and theories in CSR undermines the rationality of religious beliefs; 2) positive relevance: religious beliefs need not be irrational in the light of CSR, in fact CSR may actually support the rationality of religious beliefs.      Two lines of argument can be distinguished among those who argue for a negative relevance: a) the natural explanations that are provided by CSR are preferable; and b) religious beliefs are irrational because they are caused by unreliable cognitive mechanisms.      Among those who argue for positive relevance two arguments can be distinguised: a) religious beliefs seem to come naturally to humans and therefore are probably true; and b) CSR confirms empirically that we are equipped with a "divine mechanism" that there are reasons to believe is reliable.      The conclusions are: CSR has negative relevance to beliefs in "finite supernatural agency", but not for the faith of "infinite supernatural agency". First, the first type of beliefs is easier to explain by being generated by unreliable cognitive mechanisms; secondly they are difficult to integrate with what we otherwise know about the world. A category that falls outside the scope of CSR and thus not even potentially can be affected, is beliefs in "supernatural non-agency". / The Impact of Religion – Challenges for Society, Law and Democracy