The opinion rule of exclusion and the use of expert testimony, like much of the law of evidence, developed out of the adversary system of trial. Not until the Eighteenth Century was the opinion rule established, and although the courts had used witnesses with special knowledge to assist them in obtaining needed information, expert witnesses were not used in the modern sense.' There were also inquisitorial hearings in which the inquisitors were all persons with specialized experience, but this was not similar to the use of experts today as the inquisitors determined the issue upon the basis of their own information. This was a special jury or a jury of experts to decide upon matters within their own knowledge. Indeed, much might be gained from the inquisitorial practice by having the experts exchange the information which they had with each other and then determine the conclusions to be drawn. With the rise of the adversary system in which witnesses were looked upon as being called by the parties and expected to represent their position in the case, it was not surprising that the use of scientific proof developed into a testimonal battle of experts.
5 Vanderbilt Law Review
Available at: https://scholarship.law.vanderbilt.edu/vlr/vol5/iss3/7