The Soviet economic system is based on the principle of public ownership of all means of production. Consequently, private enterprise in Soviet socialist economy as a rule is not tolerated, allegedly to exclude unearned income and to prevent “exploitation of man by man”. From the Soviet point of view, private enterprise is a disturbing and unpredictable element in their system of central planning, command economy and Party control. If it is not considered an outright crime it is characterized in the Soviet Union as a parasitic, socially unnecessary activity undertaken primarily for personal profiteering and for obtaining unearned income – all unacceptable activities in a socialist society.