There’s a guy with lilac hair sat diagonally opposite, a sort of silvery-lilac glimmering, and I look away to scowl, because he just put his feet on the seats. Outside the train window the Hertfordshire scrubland rolls mistily past; I don’t know whether I’m annoyed with the young man’s feet-on-seats selfishness, or (be honest) with the colour of his hair. Be honest, indeed: a bit of both. “Ridiculous way to look.”

The ticket inspector comes through. Lilac puts his feet on the floor and shows his ticket. “Surprised he’s got one,” I think, smugly, holding up my season card. The inspector doesn’t acknowledge my smile: few people do once you hit middle-age, I find. Or maybe she read my thoughts. But what’s this? “I like your hair!” she trills at Lilac. He grins, and I see him, properly, for the first time, and realise: in another life, I would have found him beautiful.

But not in this one. What’s going on? Leave this middle-aged scowling fool for a while. We’ll come back to him, but I’m hungry now, so let’s grab something to eat.

How about a Gregg’s? Sausage roll, yum yum. Except I’m vegetarian, and don’t eat (porky) sausages. (Insert puerile joke here). But on Tuesday Gregg’s launched a rather nice-looking sausage roll that’s free from any animal products. A bona fide vegan roll is on the High Street: Listen To Your Belly Groan!

This age of semiotics is breaking us By John Gray

Surely, in a country ripped apart by Brexit, on a planet choking in its plastic waste, lost in its unimportant corner of a coldly indifferent universe: surely the arrival of a sausage roll that vegetarians can eat is a simple Good Thing.

No. Because: vegan. Plant-based foods invoke the same reaction in many that lilac-dyed hair does in me: a sign-based trigger, and on social media (where else?) all hell broke loose. Piers Morgan: “No-one was waiting for a vegan sausage, you PC-ravaged clowns.” Danny Baker: “Call it a vegetable extract mush roll”. The kerfuffle over the insertion of processed soya into a puff pastry blanket led UnHerd writer Julie Bindel to remark, caustically: “This is a major atrocity and human rights violation.”

Choices we make, about hair colour or food or many other things, have developed a meaning that transcends their actuality. This is very, very weird, if you think about it: the food I eat should have literally zero bearing on my views about politics. Your hair colour should contain literally no information about your vote.

But the statistician in me, who looks for patterns and imbues them with meaning for a living, won’t accept that. It’s simply not true that a randomly-selected vegetarian is as likely to be Tory Graeme as he is to be Labour Jeremy; the vegan activists who annoy Brighton’s restaurant customers are hard-Left ‘social justice warriors’. Equally, I’d be pretty confident that while the link between dyeing one’s hair pink and choosing to march through central London screaming about “austerity” would be weak, it would still, however, be positive.

This age of semiotics is breaking us By Graeme Archer

We all do this – imbue meaning to signs – what’s more, we must, because without them you can’t draw a map to navigate life, and without learning the meaning of the signs on the map, you’d just be blundering around in a life-long game of blind man’s buff. Willfully to understand nothing beyond immediate sensation, and never to recall similar sensations from the past, is never to learn from experience.

But it’s gone wrong: a vicious circle has taken hold. Because of the mild correlation between signs and politics, irrelevant facets of our make-up are fashioned into the armour of our caste: signage as tribe. I’ve heard myself in recent years apologising to guests for my diet, not because I worry they’ll dislike lentils, but because of what I fear they’ll infer about my politics.

I’d call this the age of semiotics, and it has terrible consequences. As more and more signs are tribalised, so the deconstruction of signs – semiotics – has become our chief political diagnostic: Pink hair? Vegan? Probably a Corbyn supporter, so probably anti-Semitic. Safely hated. Or: England flag in window? White working-class? Probably a Leave voter, so probably a racist. Safely hated. I haven’t even mentioned the hijab. Or the saltire. It’s like looking at a street sign and deliberately believing that name tells you everything about the infinitely-varied human life on the street itself. Everything.

This age of semiotics is breaking us By Graeme Archer

When signs become politics, everything suffers, including – of course – art. What Sarah Phelps, the writer of ‘The ABC Murders’ this Christmas, seems unable to understand is that it’s not her politics that enrages (most of the writers I revere are of the Left), but her lazy signage, that ahistorical projection of Brexit onto 1930s fascism.

Agitprop writers aren’t angry young men kicking against the class system for its iniquity and waste of talent, in the hope of changing society, as in the 1950s. Rather, they’re complacent middle-aged men and women, flagging their politics for the adulation of everyone else in their tribe, and to hell with the rest of you. That’s not art; it’s political painting by numbers. (Read Niall Gooch’s superb review here.)

The solution to this isn’t ‘big’, but it does require courage. Once, in a more innocent time – all of thirty years ago – my father was driving me down Great Western Road to my student digs in Glasgow, and we passed a green-haired girl pushing her bike up from the Kelvin river-path (to feel the city air rush past her body, in the words of the beautiful song.) Isn’t it great, mused my dyed-in-the-wool Conservative father, isn’t it great that there’s a space for everyone to be themselves?

Even at the time I knew he was speaking to me and about me, his newly gay son. My father had the ability to note signs but not to be skewed by them; to see them, but never to assume that life is no more than its visible surface. He never reduced me to the sum of my labels.

No more should the rest of us. Look up from the rolling countryside outside, Graeme. Look at the man across from you on the train, and smile. Who knows? Maybe you can share a vegan sausage roll. Next stop: Stevenage, where this train terminates. All change, please.