Seen from outside : the professional identity of librarians

A profession has a strong social identity when it controls these three points : the practical and theoretical knowledge it leans on ; the unity and force of conviction of its representative authorities ; its reflections and practice towards its public. With the use of the methods of reflection and the lessons of science in information and communication, how can the question of the identity of libraries be read ? How can the knowledge of science of information and communication contribute towards the constitution of a library science ? What are the analyzing tools it offers to speak about the professional identity between training and practice or about the relation with the public ?