Who is Muslim ?

Today Muslim world in general and Pakistan in particular is watching lot of religious intolerance. Each one of us is trying to define every other as infidel on the basis of his/her own definitions. There is some issue with either our education system or may be with our moral upbringing that inspite of being educated we are unable to tolerate others. This is not only related to religion but to every other walk of our society also. We should give it a deep thought.