“I want you to frame a question, as sharp and clear as possible—one to which you do not yet know the answer, but desperately want to know, and expect someday to know. Pretend to be David Hilbert. The Millennium is approaching. Issue a challenge to the quantum theorists of the 21st century. List the key questions they should seek to answer. Hard questions, but not hopelessly hard, questions whose answers could transform our understanding of how the physical world works. I need to know what the question is. Then, perhaps, I can be more engaged in the search for the answer.”