Shades of Arbitrary Definition.

As a writer, one of the questions that always intrigued me was the difference between twilight and dusk. Or I suppose it would be more precise to ask at what point one turns into the other.

There seems to be a consensus that twilight starts after the sun has set and the daylight begins to fade, and that dusk ends when the night becomes as dark as it’s going to get. Right, but where does the demarcation lie?

I was standing by the greenhouse this evening, pondering whether it was still twilight or whether the dusk was gathering. (‘Gathering’ goes almost as well with ‘dusk’ as it does with ‘gloom,’ even though it lacks that extra alliterative thrust.) I realised that the foxglove close to where I was standing was still recognisably pink, and I decided henceforth to make that my definition. If colours are still clearly recognisable, it’s twilight; if detail is recognisable but the colours are fading to grey tone, it’s dusk.

But that depends on the quality of your eyesight, and colour vision in particular, which is all about the variable sensitivity of an individual’s rods and cones. Isn’t life complicated?

*  *  *

On a related, though less wholesome, theme, I knew a Customs officer once who had worked at the ports seizing printed matter that was deemed to be pornographic. I asked him how he defined pornography. ‘Well,’ he said, ‘if it puts me off me tea, it’s pornographic.’

See what I mean?