On the issue of the principles of participation of an expert in legal proceedings and operational-investigative activity

The article is presented the importance of the principles of constitutional, criminal, civil-legal proceedings, legal proceedings on administrative violations and operational-investigative activity in activity on the application (use) of the special cognitions (knowledge) of an expert. On the ground of the made analysis it is proposed a content of the conception the principles of participation of an expert and their classification to the followings: 1) the principles, established by the legislator (the rule of law, respect and observance of human and citizens rights and freedoms and others); the principles, formulated by investigative, court, expert practice and they are substantiated by science (reliability, reasonability, sufficiency and others)