While literature on comparative criminal procedures considers the relative merits of adversary and nonadversary procedures, it is argued that both adversary and nonadversary systems are rooted in the classic scientific method. Nonadversary procedures emphasize separate investigations conducted by different personnel, such as police, prosecutors, magistrates, and judges. Adversary procedures make a sharper distinction between the investigative pretrial stage of inquiry and the proof stage of trial. The classic scientific method of proof assumes that needed evidence is collected and that a theory of proof is developed in a detached, value-free way. This method has been challenged, however, and a central criticism is that police resources available to assemble a case and question witnesses, weigh evidence in favor of the prosecution. The dialectic method of proof is based on the idea that participants in criminal proceedings be free to engage in dialogue with themselves and others and not be constrained by forces that may prejudice the inquiry result. It is not easy to apply the dialectic method to legal fact-finding procedures when there is a clear need for an ultimate court of appeal to insure a decision is reached and when there may be other values apart from fact-finding that compete for importance. What seems to be required is that the dialectic method work throughout the entire fact-finding process and that all process participants justify their inquiry methods. 69 references.