과학증거의 자유심증주의 제한에 대한 비판적 고찰

Recently, scientific evidence has been a substantial challenge on korean criminal justice system. Korean supreme court has produced some decisions in which a judge's discretion can be restrained by some sorts of scientific evidence, such as DNA evidence, blood type analysis evidence, etc. Korean supreme court seems to open up a new era of reliability of scientific evidence which just has been considered in relation with admissibility of evidence. Most of all, access to reality is not substituted by scientific and statistical certainty. Truth in criminal justice system is the truth that exist in distribution of right, limit of perspective and system, and often many errors. Although scientific achievement can partly help cure legal system, its exaggeration must lead to another unreasonable outcome. Particularly, even a DNA evidence suffers from many error and misunderstanding. For example, many decision-makers in court process misunderstands a source probability of DNA analysis as a matching rate of a DNA sample with that of defendant. Also, sometimes, judges and jurors accept a shown probability of DNA as a probability of a defendant's guilt. Unlike those in common bias, probabilities regarding DNA analysis results from subjective considerations of relevant facts. Science in nature is also partly subjective and uncertain in nature. Also, weight of an individual evidence is not simply determined by its scientific method but also by a constructive argument of entire picture of past events. Any evidence may be a mere part of a narrative about facts argued. That is, fact-finding process of criminal process is largely different from that of science. Therefore, simple application of probabilistic certainty contained in a scientific evidence to fact-finding process in a criminal process is a serious error. In addition, proof beyond reasonable doubt tells us that scientific evidence by itself cannot be used to prove a defendant guilt but may be useful to disprove it. Because, with scientific evidence that is uncertain in nature and different from fact in law as a matter of its purpose, guilt-proof beyond reasonable doubt cannot be achieved.