 The posterior surpasses .9 once the prior is above approximately .008. In a paternity case, given the mother’s testimony and other evidence, it is clear that the probability of fatherhood before the expert testimony is taken into account should be higher than that, no matter what the prior probability should exactly be. Without settling on an exact value, the interval of values above .008 would guarantee a posterior probability of paternity to be at least .9. This is amply sufficient to meet the preponderance standard that governs civil cases such as paternity disputes (on standards of proof, see later in  Section 5.)