“An appellate court can hardly ever overturn primary findings of fact by a trial judge who has seen the witnesses give evidence in a case in which credibility was in issue.”
“[The appellate court] can and sometimes does test the judge’s factual findings against the contemporaneous documentation and inherent probabilities. But where findings depend on the reliability and credibility of witnesses, it will generally defer to the trial judge who has had the great advantage of seeing and hearing the witnesses give their evidence. The question is whether the findings made were open to him on the evidence”