Something is known Beyond a reasonable doubt if the laws of cause and effect make it impossible for it not to be true.
I KNOW with certainty that a 2 headed coin will come up heads if flipped.
If the coin has a heads and a tails then I dont know what it will come up as but I KNOW the probability is 50/50.
If I have 3 coins in my pocket, one with 2 heads, another with 2 tails, and another with one head and one tail and I pull one out at random and, without looking at it, flip it then I dont know the probability but I still KNOW the bayesian probability is 50/50.