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.
26.2.23
Musar approach of the Rishonim
I might have just gone with the Musar approach of the Rishonim except that their framework is faith {sinai} with reason {Aristotle}. That works for me to some degree except for the problem pointed out by Berkley that there is nothing of the heat of the fire or the sharpness of the sword that enters the mind to give an idea of heat or fire. To see that point clearly it helps to read Thomas Reid, the common sense philosopher. [There are also problems in Aristotle's Metaphysics.] So the purely Aristotelian approach is not possible except with some sort of modification. Thus, the three critiques of Kant are a necessary development. That leaves me however with some problems in Kant which were noticed almost before the ink was dry. From that emanated a few schools. To me the one that makes the most sense is Jacob Fries and Leonard Nelson. ["Why not Hegel?" you might ask. For me, the reason is the dialectic method is a tool of reason, but not the only way reason progress. Empirical evidence is needed. There is the problem of pure reason alone that Kant pointed out.