You're not what you eat any more. Or if you are, I'm a salad. Or a mug of coffee, perhaps - a grande Americano, no room, in the slang du jour.
You're what you wear, I think, instead.
David Cameron and his summer holiday wardrobe of navy polo shirts bears this out. So what: he shops at Boden. Thousands do. So what, either his polo shirt has lasted for many summers or else he has an entire wardrobe of similar tops. Mid-life man is either a creature of habit or a creature of sartorial crisis whose wardrobe would frighten away the lion of Narnia. The Camerons' off-duty attire was scrutinized throughout what passed for summertime. Was Samantha wearing high street? Had she abandoned the high fashion of her own successful career to be a bit less aspirational and a bit more everywoman, a bit more like us? Did Camerons' outfits prove to us that we are 'all in this together'?
And on it goes. Recent scandals aside, there's an entire industry devoted to documenting the fashion choices of Kate Middleton (or, when she's more formally attired, Catherine, Duchess of Cambridge). Labels are sourced and photos dutifully catalogued; some websites and magazines even tactfully indicate how less regal shoppers can emulate Kate's look on a high street budget. There are identity role models for every taste: Cheryl Cole or Jennifer Aniston. Gary Barlow or Gareth Malone. In the summer of 2012, even the Olympic tracksuits and uniforms of many countries were designer - today the red carpet or front row, tomorrow the medal rostrum, dahling. You're someone. You've arrived.
Most of us, when we're shopping, have probably absorbed this stuff, whether we really want to admit to it or not. Most of us are thinking about a mental image of ourselves, based on an image we've seen of someone else.
Picture it. It's an early autumn Saturday; it's early. There are a few lingering tourists, but the locals are back home for the winter: the schools have started their Saturday morning sports again, and the swimming club is back in the water. The shops and cafés are full of waiting mums, digging through the Autumn fashions and then into their cakes and lattes. Promising myself an Americano as a reward, I make my way past the supercilious assistants and scan the rails of the more fashionable end of the Ladies' department of a local store. I can feel my heart sink as I search. If I'm looking for the outfit to make me someone, and I don't want that someone to be just anyone, then where on earth am I going to make a start?
It's impossible. Do I want to be the mid-life stereotype in the mid-calf tweed ensemble? The mutton-as-lamb tragedy in the too-short-for-my-age dress? The girly, approachable Mummy-substitute in pretty florals, or the mid-life goth in the carefully distressed draped cardigan? None of the above. As my shopping trip takes me further, my heart plummets further beneath the paved pedestrian zone, and in my despairing distraction I am almost run over by a delivery van.
But suddenly I see it. The garment which makes everything all right, which redeems my morning and sends me off to drink my coffee happy. It's there. The below-the-knee mid-brown belted shift dress with the purple lining, easily the most hideous item I've seen for years. But it's not as simple as this: this dress and I have history. I saw it first in another branch of the same chain during the summer holidays. I took a quick, covert photo of it on my phone, that day, sent the photo to a friend with the caption, 'Just wait: someone we know is bound to wear this dress this winter. Let's make a deal to try to spot it. First one who sees it wins, and the loser makes them coffee.' Seeing that dress again, I knew that, even if it's hard to find that one defining outfit, and even we're all subjecting one another to endless sartorial scrutiny, it's going to be okay, because I'm still going to be able to share a joke from time to time with people who somehow don't seem to define me by how I dress. And that was something to make me smile.
Perhaps we are what we wear, whether we're all in this together, on a magazine cover or fashion show front row, the pedestals or podiums of influence. The fact that I can still laugh at these things, whether it's at the Prime Ministerial true blue polo shirt or the hideous brown dress which I will never wear, and the fact that I know that other people find it funny too, makes it feel all right.
Because that's the kind of complicity which will never go out of style.