The presumption of evidence is a multifaceted concept in the interplay of probability, burden of proof, standard of proof, and equity. In a general section, the author analyzes the relationship between empirical rules and scientific concepts of probability, highlighting the limitations of proof based on objective probability data. In the medical malpractice section of this work, the application cases of the presumption of evidence are examined, and its prerequisites are explained. By placing the presumption of evidence within the evidentiary system developed by jurisprudence for medical malpractice cases, the author discusses the consideration of probability judgments in medical liability lawsuits. Finally, alternatives to easing the burden of proof in medical liability law are explored.