> a non-expert will have no idea how much weight each fact should have In theory, that is the purpose of the lawyer(s) -- to try to ground the technical expert

> a non-expert will have no idea how much weight each fact should have In theory, that is the purpose of the lawyer(s) -- to try to ground the technical expertise in a way that the jury (and often the judge!) can understand and assign value/import/trustworthiness/credibility to the testimony and exhibits they are given. in theory.