text: If I remember the jury instructions correctly, "reasonable doubt" is the doubt that it would take for a reasonable person to act. Reasonable doubt is not beyond all doubt.\nIt's a tough standard, and it's subjective.  But I think it's about the best one that can be developed. \nI think it does not matter too much, because in most cases you've got jurors who are _sure_ (99-100% sure), jurors who are sure that the person is not guilty, and then people who are not quite sure (in the maybe 60-70% range).  I don't think defining "beyond a reasonable doubt" helps for most of the jurors. At most, it helps for group (3), but so long as you tell them it's more than "more likely than not", they are able to act on their instinct.