It's actually worse than that, it's more of a popularity contest. Whoever the judge/jury find more convincing. I doubt any of them (judge/jury) would know how to apply probability or likelihood to any of the evidence presented. They just use their "common sense", which is just another way of saying "opinion", to determine who they believe more, and it's usually the more articulate side. Just be clear, I'm not saying he isn't guilty, just that I don't know and neither will anyone outside of those involved.