That there are two kinds of people in this world is a truth universally acknowledged; what exactly it is that divides the world is where the disagreements arise. Extroverts and Introverts? Optimists and Pessimists? (Or as famed fictional pessimist Sir Humphrey Appleby would have it, Idealists and Realists?)

Left-wing or right-wing? Liberal or Conservative? North or South of the River? Blur or Oasis? King of Rock Elvis, or King of Pop Jackson? Tea or Coffee?

Is it as a t-shirt of mine proclaims? “There are 10 kinds of people in the world, those who understand binary and those who don’t.”

Or perhaps the crucial distinction is the one that cleaves my own family right down the middle and once nearly caused a family Christmas circa 2004 to descend into a bitter, full scale row: the division between those who think that George Bush did the things he did because he was stupid (myself and my mother), and those who think he did the things that he did because he was evil (my brother and my father).

No. The longer I live, the more I am convinced that all such divisions pale before that which truly divides us. I speak, of course, of the division between people who believe in a thing called “fresh air” and those who believe only in not being cold. Or to put it another way, between those who like their windows closed in winter, thank you very much, and those who insist on opening them at least once a day even when the temperature outside is so far below freezing talk of monkeys getting their balls frozen off is not mere nautical-derived metaphor.

I myself am firmly in the camp of those who believe so-called “fresh air” to be nothing more than an urban myth, no more real than the Ancient Greek’s aether, or the “molecular memory” of homeopaths. If given a choice, I would close my windows in October when Autumn arrives, and open them up again come April, having given spring a month or so to get its feet under the table.

Of course, in matters such as these choice is not always on offer. The picture at the top of the post is the window currently sitting open just to my left, from where it directs a cold draft across my forearms. Yes, having first married a committed member of the “open windows” camp, I’m now working with one too.

Dammit. Maybe I ought to start wearing jumpers.