Living in a small village, and working from home, there is rarely more than a pane of glass excluding me from the real world. And by that I mean the world of wind and rain, grass and mud, birds and beasts. In fact as I write now a heavy, sleety shower is spattering on the skylight window a few inches above my head. It's strangely comforting, like lying in a tent in a downpour - I'm warm and dry while all around is cold and wet, but I can still smell the grass and hear the birdsong.
And every day there are many reasons to go outside. I feed the hens, walk the dog, dig the garden, cycle to the town. I know I am one of the lucky few, with a job that allows me this freedom.
But every Wednesday I get a taste of what most people, sadly, have to endure every day. I'm doing a year-long course in horticulture, and sit in a neon-lit lecture theatre with the blinds drawn (the equivalent of the office) all morning, with no idea what's happening beyond those four walls. As the morning draws on I feel a creeping numbness, almost inertia, as the room gets stuffier and the lights dimmer.
Later, we emerge blinking into the sun, or wind, or (more rarely, as it is in Edinburgh) rain, to study some real-life examples of the plants we have been learning about, in the Royal Botanic Garden. It always feels like waking up again, or like the feeling you get when you come out of the cinema after seeing an engrossing film - as if you are remembering a different world you had almost forgotten about. And I wonder if there is a cumulative amnesia in those that have to sit in windowless offices and shops, factories and call centres, day after day. Does the indoor world become the only reality, and the outdoor world a brief dream?
Some would argue that this is the real world. The world where the money is made, the money is spent, the deals are struck, the communications communicated. But how can that be, when the air we breathe, the water we drink, the food we eat and the earth we walk on are all beyond the walls that enclose us?
On a planet where more than 50% of the population now live in urban environments there has got to be a move to fling open the doors and windows again, so that people can step outside and remember which world is actually the real one - the one that keeps us all alive.