I was saying earlier that it's really strange - you can almost step outside yourself and observe yourself running, and that's what I was doing.
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.
If you're old enough to have a job and to have a life, you use Facebook exactly as advertised, you look up old friends.

