Suppose that I know all the laws of physics and the position of all the atoms in the universe. I flip a coin. Obviously I will know with 100% certainty what the outcome will be.
Suppose I am a mere mortal, I will only be able to say that there is a 50% chance of heads and a 50% chance of tails.
So probability is a measure of our ignorance? That cannot be right! Probability is something intrinsic to reality. But how can an uncertainty be intrinsic without reference to a knower?