Nietzsche: "Those Who Dance Are Considered Insane by Those Who Can't Hear the Music."
I think the entire movie revolves around this sentence of Nietzsche. This movie operates in two levels: philosophical and sociological. Sometimes these two are completely intertwined.
Bahram, the protagonist of the movie, is a writer who is surrounded by a culture that fetishizes sorrow and death (mostly because of religious beliefs). Exposure to this vicious circle of sorrow (with the assumption that reward is in the afterlife) have made Bahram numb. He can't write. Because in a sense he is dead! He is surrounded by death (death of friends, religious rituals of a neighbour, the depressed son, etc).
Then, all of a sudden, due to a rare encounter, he starts to hear the music of life. As a result, he can't stop dancing (while others called him insane). He sees life to a greater depth. He feels and hears the music that resides in everyone. However, because of the challenges in the everyday life (that one may refer to them as samsara) and the dominant culture of sorrow, people forget about this music. Except for children!
Children are innocent. They are the embodiment of life in its purest. That's why they can hear the music.
I finish this review with another quote from Nietzsche:
"Remain faithful to the earth, my brothers, with the power of your virtue. Let your gift-giving love and your knowledge serve the meaning of the earth. Thus I beg and beseech you. Do not let them fly away from earthly things and beat with their wings against eternal walls. Alas, there has always been so much virtue that has flown away. Lead back to the earth the virtue that flew away, as I do-back to the body, back to life, that it may give the earth a meaning, a human meaning."