Background: Reason is one of the main elements of criminal proceedings. Historically, criminal justice systems are usually divided into two general types: in the first type, called the "legal evidence system", the reason is only what is stated in the law, and therefore the judge has the right to document his sentence other than It does not have. In the second category, which is called the "system of persuasion of the judge", in addition to the evidence permitted by law, the judge can study other evidence and even evaluate, injure and modify the evidence presented, but the issue that is important and is very important from a legal and moral point of view is the basis of the judge's knowledge and how to achieve it. Therefore, the purpose of this article is to analyze science and knowledge from a philosophical-ethical perspective from the perspective of evidence of criminal litigation to provide the conditions for explaining the knowledge of the judge and ways to achieve this knowledge as the most important evidence of litigation. Conclusion: The knowledge of the judge is one of the positive reasons in criminal cases that obtained as a result of examination, exploration, and investigation of the judge in the referral cases for him. Science can be valid and cited when the reasons for achieving it are legal and in accordance with judicial ethics. Therefore, personal knowledge that does not have a rational and legal basis and origin cannot be a criterion and document for issuing a judge's verdict.
