I respect you two immensely but you seem to think that judges get their ideas from thin air and that somehow a judge is free to make opinions from fiat.
Do you understand anything about the process whereby precedents are laid down and laws are made? I suggest that you start reading your history. Start with Maine's Ancient Law, then move on to his Early History of Institutions, After that pick up Either Blackstone's commentaries on the laws of England, or Coke's Institutes.
In brief, the use of precedent to create a new interpretation does not come from thin air. This is not an either/or situation think of it as both/and. The process of adjudication is inductive. First one considers the facts of the individual case. Next one looks at precedent to see how similar cases were handled in the past. After that a judge has to consider the changes in customs from the precedent in question to the present. Lastly one must think about the impact of a potential decision and the possible precedents created by a ruling.If you argue that both are true, then you have just proven my point about absolute power -- the judges are free to either look at the original intent or freely interpret it based upon modern situations. Any interpretation they want can be justified, and there are no checks or balances over them.
Think of the process of adjudication as reconciling societal conceptions of justice with statute law. One small precedent at a time. The process is one of gradual evolution not one of drastic change.