I think you have to think about the probabilities on the larger scale because there are millions of cases a year. so lets pretend everyone at HLS (about 1600 people) was put on trial and you were right at your level of confidence. at 90 percent you are comfortable locking up 160 people.
What if you had a trial where they said - we are 100% sure the murder was committed by someone who accessed Room X on Sept 22. Def A accessed the room 99 times that day (and was in the room for 99% of the time the room was occupied) and someone else accessed it once. Are we 99% sure it was Def A?
let's be honest, this is about how comfortable a person is with potentially being wrong and sending someone to jail. I don't think every juror who has ever voted guilty has been 99% sure, but I think there's an underlying feeling of "I don't want to risk being wrong"
I wouldn't - I think math is pretty artificial - it's an abstraction of reality, not reality itself. You would have to transalte the percentage to some practical instruction anyway, since you can't actually quantify the likelihood of guilt
If I have to give a number, there's a difference between what I want and realistically what that number is. If the question was what do you want, then my number would be 99% or 100% you need to be extra certain if you're going to have years off of someone's lives by putting them in jail.
A charge is proved beyond a reasonable doubt if, after you have compared and considered all of the evidence, you have in your minds an abiding conviction, to a moral certainty, that the charge is true. When we refer to moral certainty, we mean the highest degree of certainty possible in matters relating to human affairs -- based solely on the evidence that has been put before you in this case.