Evolution of music ability has been considered a mystery from Aristotle to Darwin and as no adaptive purpose has been identified yet, making music is still a puzzle for evolutionary biologists. This chapter considers a new theory of music origin and evolution, identifying a cognitive function of music which helps overcoming cognitive dissonance based on the unification of consciousness that is differentiated by language. According to this theory, music is fundamental for cultural evolution. The reason for music strongly affecting us is that it helps overcoming unpleasant emotions of cognitive contradictions, which are conditions of accumulating knowledge. The chapter considers experimental evidence supporting this theory and the joint evolution of music, culture, and consciousness.