Learning is finding out what we already know. Doing is demonstrating that you know it. Teaching is reminding others that they know just as well as you. You are all learners, doers and teachers. – Richard Bach
It is no good getting furious if you get stuck. What I do is keep thinking about the problem but work on something else. Sometimes it is years before I see the way forward. In the case of information loss and black holes, it was 29 years. – Stephen Hawking
