I studied Bayesian theorem as part of my "Masters in A.I." curriculum.

Just for your interest, I really struggled with Bayes for the longest of time. This "mathematical rule for inverting conditional probabilities" just wouldn't click with me. Part of the reason was me (of course) but in retrospect, I can also see it was not fully understood by our Lecturer. Because nobody in my class "got it" the first time around!

Decades later, I stumbled upon a YouTube video that used neat graphics to explain Bayes in motion, so to speak. Then I "got it"!

When applied appropriately, Bayes is very powerful, and I understand it has been used by the Insurance Industry for decades already.