My poetry has been called polyphonic, which is to say that I have always been full of voices speaking; in a way I consider myself an instrument, a medium. My friend Jeanne Hersch, who introduced me to the existentialism of Karl Jaspers, used to say, “I have never seen a person so instrumental,” meaning that I was visited by voices. There is nothing extraterrestrial in this, but something within myself. Am I alone in this? I don’t think so. Dostoyevsky was one of the first writers, along with Friedrich Nietzsche, to identify a crisis of modern civilization: that every one of us is visited by contradictory voices, contradictory physical urges. I have written about the difficulty of remaining the same person when such guests enter and go and take us for their instrument. But we must hope to be inspired by good spirits, not evil ones.
Czeslaw Milosz (InterviewThe Paris Review) From here