A class only becomes a class for itself when its members are fully conscious of the true nature of situation, when they are fully aware of their common interest and common enemy, when they realize that only be concerted action can they overthrow their oppressors, and when they unite and take positive, practical steps to do so.

When a class becomes a class for itself, the contradiction between the consciousness of its members and the reality of their situation is ended. A class becomes a class for itself when the forces of production have developed to the point where they cannot be contained within the existing relations of production.