There is a painters' and decorators' supplier not far from where I live. I went there early this morning to get some white spirit and a paint brush. I needed to paint some book shelves I had just bought to accommodate my most recent acquisitions – the consequences of a book addiction that buying a kindle was supposed to cure.
It's not really the kind of store that targets the general public. Instead it caters for professionals and at that time of day it was full of tradesmen on first name terms with the guys behind the counter, putting in bulk orders and loading up their vans. But as I waited my turn to be served, two middle aged men in paint stained overalls walked past me.
'You know just before he died,' one of them was saying, 'Einstein was working on a theory of everything.'
'What does that mean, exactly?' his companion asked, a half-smoked cigarette dangling from his lip.
'A single equation that would reconcile relativity with quantum mechanics,' the first man said.
That was all I heard. They disappeared somewhere amid the aisles of exterior masonry paint. I went to the counter and asked for a brush.
'What size?' the man asked.
I hadn't thought of this. I held out my thumb and first finger, about a finger width apart. 'Maybe this size?' I suggested.
The man turned, took a brush from a rack behind him and handed it to me without a word.
I felt distinctly out of my depth.