Portion of Expert in Application & Evidencing by Helpfulness Science (Comparative Study in Iran, USA & French Legal Systems)

In discourse on science and litigation, the expert is a traditional role in legal systems, whether as witness-like expert or as separate evidence. The approach of legal systems is not same as witness-like expert. Developing rational standards along with public acceptance of results and methodologies and principles that are relevant to facts and data is the approach of the US legal system to evaluate the knowledge of the expert opinion. In civil law system, including Iranian civil law, some criteria are emphasized, but the principle of free evaluation of the court is criticized in this article. The question is how the judge can ignore the knowledge gained by the expert opinion if the standard of validation and helpfulness is acquired. The link between two seemingly unrelated proofs - “witness” and “expert” -  opens up some nodes in accepting the “science” in courts. Iranian legal system should take some rational criteria for evaluating experts’ opinion.