Occasionally, a TV show or a film or a book becomes such a towering mass phenomenon it moves outside its medium to serve as a focus for nationwide arguments on everything from the state of the nation to the likely direction of our children's futures.
We pick apart its morality, its representation of men and women, the impact it has on its millions of followers. Two tribes inevitably develop, as is our naturally adversarial wont. The wider the audience, the more entrenched and fiery the warfare between champions and naysayers. It's a kind of modern gladiatorial battle, and these days, Twitter is its arena.
But enough about Masterchef. Ha, I jest. Though there are some folk who'll say Masterchef has a more credible claim to such significance; at least it's primarily aimed at adults, they'll point out, unlike the programme which dominated the cultural conversation last week; Doctor Who.
As regular readers of this column (hi Alan!) will have noticed, I have no qualms about 'coming out' as a dedicated Whovian, even though the confession often sees me pilloried by sniffy fellow arts journalists.
I'm not particularly drawn to the very earnest (NOT a criticism!) conversations some fans enjoy about the wider meaning of particular plots or characters. There may well be references to the Holocaust, Christianity and Totalitarianism in past episodes but – and it pains me to say it, friends – I do think these issues are rather better addressed by the likes of Primo Levi, Christopher Hitchens and George Orwell.
However, I do think the massive, deeply felt passion that Doctor Who stirs worldwide (the 50th anniversary show was broadcast in 75 countries and broke audience records for BBC America) is a cheering sign of a valuable human trait. The queue of sneerers on Twitter and other media generally focus on the fuss being made by adults over a children's TV programme. Over-16s fans are derided as pathetic/tragic/backwards, out of control slaves of a show in which monsters who look like potatoes are supposed to be taken seriously. Sean Hughes asked on Twitter, while 10 million of us were glued to BBC1, if 'CBeebies' was finished yet.
I understand this argument. I fight the urge to stereotype Top Gear aficionados the same way. But even Top Gear, though I don't get it myself, is part of this human instinct I love; the internal cherishing of an ungainly, irrational, fierce passion for something which gives inexplicable joy, but is ultimately inconsequential.
You could call it a Geek Force. Oddly, women are often regarded as having escaped it. It certainly has roots in childhood, which might be why Doctor Who is such a popular example, being for many forever linked to our earliest memories and able to resurrect, within a few seconds of its theme tune, a primal stir from our past.
Those who 'rise above' such enthusiasms, who still regard 'nerd' and 'wonk' as putdowns, often overlook their own vulnerabilities to comparable compulsions; anyone who's ever cried at a football match, oohed and aahed over a fast car, or travelled miles to locate that final, completing addition to a record collection, should feel a kinship with us Who fans. There is no intellectual defence for our exaltation. But boy does it make us happy.
I have met a few people who couldn't be reduced to a starry-eyed child or an evangelical geek by any subject at all. I found them to be the dullest company I ever encountered. But I must admit they were very grown up. Very grown up indeed.