Abstract
The author points out the great importance of expert proofing for justice, state bodies and citizens. He points out the historical concepts of the expert's role (expert as a "aide of court or as a " scientific judge").
Today, the expert opinion is considered one of many kinds of evidence, that does not hold any privileged position in the process ofproofing. It is subject to all the usual principles of proofing, namely the principle offree evaluation of evidence.