What are the motifs in When Nietzsche Wept by Irvin D. Yalom?

Freedom is recurring idea in the story. The most obvious symbol of this theme is the birdcage full of pigeons in Breuer's study. He has used the pigeons for many years in his laboratory experiments as he has studied equilibrium in the inner ear. When he feels trapped and wants to flee his marriage and his patients, he fantasizes about letting the pigeons go free, allowing them to fly out the window. Of course, he doesn't really set them free, but his desire to do so shows how much he wants freedom from his current situation.