Portman illustrated this point with a story about preparing for 'Black Swan,' the film that won her the Academy Award. She trained obsessively in ballet for a year, pushing herself to a level that no one — including her trainers — thought possible. She arrived on set believing she could do things that professional dancers told her were impossible. The magic, she said, was in the not knowing. If she had understood how difficult the dancing truly was, she never would have attempted it. Her ignorance of her own limitations gave her a kind of accidental courage that produced extraordinary results. The lesson wasn't to remain ignorant forever, but to recognize that the window of naive confidence — before you learn all the reasons something can't be done — is a precious resource that should be exploited rather than feared.