more light
In case the previous hint was too oblique:
Come to my choir's concert tomorrow (if you're reading this the same day as I'm writing it). Church of St Edward King and Martyr, 3pm, Saturday 2008-02-09, about an hour. £7, or £3 if you have the good fortune to be a student and able to prove it.
Which reminds me of a story from many years ago. I was at the railway station in Cambridge and wanted to get a Young Person's Railcard. The rules were something like "you can have one of these if you're N years old or less, or if you're over N years old but a student". So, I go to the window and explain that I'm a student and want a railcard. Do you have the paperwork to prove you're under N years old, sir? Er, um, no, it seems that I don't have the right documents on me. But look, I have this and this and this to prove I'm a student. So can you prove that you're over N years old?
Clearly Bradley (for some reason I have always remembered his name) was a devotee of intuitionistic logic, according to which "A or B" is provable only if either A is provable or B is provable.