Bayes Theorem, and epdaws where have you gone?????

[Worm75]

So I was kinda bored today sitting at work, and going through some old favorite posts that I have on my homepage, when I got the idea to look at some posts from my favorite posters. I started looking at some of the last posts that epdaws had, when I came across him referencing Bayes Theorem in this post Bayes Theorem

Wondering if any of you SSNL geniuses out there can shed some light on this for me. I looked it up in Wikipedia and couldn't make heads or tails from it.