Difference between supervised and unsupervised learning?

well , in supervised learning there must be a human (a teacher) to intervened , i.e. the desired response of the system is already known so the network is make the system to respond as the desired one. in unsupervised learning is the exact opposite of the supervised, in whichThe outputs are not known, so the network is allowed to settle into suitable states by discovering special features and patterning from available data without using an external help