@igm,
Logic starts from axioms. It cannot test the validity of those axioms i.e it cannot test "existence"
per se, it can only test inferences from such axioms. Thus "God created the Earth in seven days" can be tested, whereas "God exists" cannot.
Rationality, is about "making sense", in terms of social functionality For example, Evans-Pritchard cited the Azande belief in "witchcraft causing criminal acts" as an alternative rationality to Western ideas of culpability. So when an Azande miscreant was tried by a Western court, the verdict was not accepted by
any of the parties unless the entrails of a ritually slaughtered chicken had been examined. This "rationality" was s
ocially functional in Azande society, just like different religious beliefs are socially functional in other societies.