Today I'm going to tell you about a formative experience of my childhood. (I can't prove that it was a formative experience, but it's one of the few I can remember from its time, so it's probably fair to assume that it had some effect on me.)
One day in primary school, we were all told to draw pictures of rivers. (Presumably, in that time before the National Curriculum, it was permissible for the teachers to select tasks according to their educational value rather than by government diktat. I don't know whether today's children learn to draw pictures of rivers. Perhaps they don't need to.)
I was, I suppose, a child of modestly wide experience. I had seen rivers on more than one occasion-- notably, the Thames, in my then home town of London. I knew what rivers look like: they are wide, and they are brown:
So I drew a wide, brown river.
When the teacher came round, she criticised my work, on the basis that rivers are made of water, and water, as any fule kno, is blue.
I responded that, whereas rivers may be made of water, I had seen rivers and they are not blue. Rather, they are brown, as I had drawn. By way of reply, she told me that I was wrong; that I was being petulant; and that she would prove me wrong by showing me a picture of a river.
Which, after some time she did, calling me to her desk and saying -- I paraphrase, as I cannot remember her exact words -- ``Look at this picture of a river. See how it is blue.''
She had a photograph of a river. I can call it to mind easily. It was an A4 glossy print with a white border about a centimetre wide; a picture of the sort of riparian paradise you might associate with Three Men in a Boat or The Wind in the Willows. It was a picture of a pretty, graceful river, wending its way through tidy, attractive countryside.
The river pictured was not as wide as the river I had drawn. But it was just as brown.
I pointed this out, saying, ``But it isn't blue. It's brown.'' I imagine -- though I cannot remember -- that the argument raged awhile in the manner of USENET; and I cannot remember its conclusion, if any was reached. The river in my picture remained brown, of course -- what is drawn in wax crayon cannot be undrawn, at least not without solvents of a type prohibited to primary school children -- and my opinion of the colour of rivers remains unchanged to this day.
There's a moral here, but I'll leave it to you to decide what it is.