Evaluation of expert's opinion validity in view of Islamic Juris prudence and law

The expert's opinion is a view of a specialist and professional person that a judge usea as useful tools for solving civil and criminal claims. This opinion is not special to nowadays law and before it was noticed as expert's idea for Islamic jurists in the Islamic jurisprudence texts. But today, with attention to specialization of science and fundamentals, it is feeling the importance of the institution more than before; in addition the rate of judge authority in acceptance or denial of the expert's opinion is very important for its effect to the result of claims. The importance of this discussion is more obvious when the expert's opinion is opposite to other reasons. So, the purpose of this paper is analyzing of expert's opinion in frame of legal and juridical presumptions and illustration of judge decides against this opinion that will happen in survey of legal and jurisprudence texts. So, several questions are arising among these discussions, for example is expert's opinion of legal or juridical presumption? How much is judge authority in acceptance of this opinion? With notice of precedent of expert's opinion in jurisprudence texts, what is the idea of Islamic jurists about it? To answer these questions, this survey considers the expert's opinion in analytical and comparative way. As a result, it is surveyed expert's opinion and rate of its credit in law, expert's idea and its credit in Islamic jurisprudence, presumptions and kind of suppositions and supposition of expert's idea and in finally duty of judge in applying of expert's opinion. Finally, the results of surveying the above discussion and answering the questions are: expert's opinion is of juridical presumptions in law and absolute supposition in jurisprudence that it results of comparison of special supposition with legal presumption and absolute supposition with juridical presumption and so the judge is not in force to accept it absolutely, but when he states his reasons, he can refuse to accept it.