Belief in God is rational.
Everything has a cause. So unless there is a first cause, then you would have an infinite regress. And then nothing could exist. Therefore there must be a first cause. Therefore God, the first cause, exists. QED. (You could prove the first step a priori that everything has a cause by noting that nothing can come from nothing. This makes it a priori, not just an empirical observation).
One problem I have noticed is דורש אל המתים. I do not know why people think it is OK to go to the graves of tzadikim when this seems to be contrary to an open verse in the Torah in Leviticus 20. Do not seek after the dead.