„Real mastery of a subject is flexibility (among other things) in applying it; and lack of mastery is manifest as rigidity – the need to do the things one can do a certain way, and an inability easily to add new things to one’s repertoire.“
Univ.-Prof. Charles Sabel u.a., „Individualized Service Provision in the New Welfare State – Lessons from Special Education in Finland“ (2011), S. 59