There's a principle at the heart of historical scholarship known as dissimilarity, but it has much wider application, especially in this Age of Too Much Information.
The idea is simple, really. When historians cast their eyes over past events to assess whether and in what ways they actually occurred, they attribute considerably more weight to accounts from people whose interests were not served by it taking place than from those whose were.
A good example is the case of John the Baptist. Almost every scholar of early Christianity, even the agnostics and atheists among them, agree that of all the stories in the four Gospels, few are more historically reliable than the account of Jesus receiving the rite of baptism from John. Why? Because the narrative, in a sense, places John above Jesus in the theological hierarchy, it is not something later Christians would have made up or tolerated were it not true.
We intuitively understand the principle of dissimilarity when we encounter the opposite; when, for example, we read, then quickly scan past, headlines like "Employer groups slam industrial action" or "Union supports workers". I mean, what else would they say? Dog bites man, plane lands safely, ho-hum.
Ninety-nine per cent of our public discourse, especially online, is made up of these kinds of predictable and self-serving statements.
That's why I sit up straight in my chair on the rare occasion people say the unexpected thing, the thing that runs counter to their interests or traditional alliances. That's where real insights can be found.
This happened yesterday morning when I got a call from a reliably conservative business leader, decidedly no fan of this Government.
For once, though, he had someone else in his sights.
"The Nats have totally lost the plot," he told me, referring to the Opposition's flailing on vaccine mandates. To him, this latest episode was the worst example yet of the party succumbing to destructive populist impulses at the expense of what he sees as the clear national interest.
Both the NZCTU and Business NZ have swung behind the Government's plans for stronger mandates and vaccine certificates, both of which enjoy overwhelming public support. For National, though, this puts them in a familiar bind. If they simply back the Government's approach, they won't get much credit in return for permanently alienating a small but vocal minority already drifting towards the Act Party and threatening their electoral prospects.
It's a similar dynamic to what happened over conversion therapy: unwilling to oppose the ban in light of widespread public support, they instead carved out an indefensible compromise. Yes, they seemed to argue, conversion therapy amounts to psychological abuse and has no place in New Zealand society, but, no, we don't think the abusers should be held to account. In the end, they just infuriated everybody.
The modern politics of grievance is not for dabbling. It is all-consuming. Even if it were possible, it would take someone considerably more fleet-footed than Judith Collins to simultaneously win over the anti-establishment fringe in a party more or less synonymous with the Establishment.
In the early Trump years, millions of column inches were dedicated to the question of how the Republican Party establishment could co-exist with the MAGA forces. It turned out to be entirely moot. There was no accommodation. There wasn't even much infighting. Trump and his supporters simply wiped their internal enemies off the face of the planet, transforming the GOP into an avowedly, unapologetically populist movement. By definition, extremists don't strike peace deals; they either win or they are defeated.
A similar, if more muted, version of this story has happened across the ditch where Scott Morrison, long considered to be on the Liberal Party's far-right fringe, today sits comfortably in its reconfigured centre. Former leaders John Hewson and Malcolm Turnbull are now among the party's most fervent critics from the left.
Are moderate remnants of the National Party similarly doomed? Are we simply witnessing, in excruciatingly slow motion, the same inexorable drift to the right we've seen in like-minded parties in Australia, the US and the UK?
Time will tell, although anecdotally I'm hearing that evangelical Christian forces continue to gain ground within the party. The highly centralised candidate selection process, controlled by a corporate-style board that screams "establishment", may act as a bulwark against the party's radicalisation. But for how long?
As the party wrestles with these competing impulses, and because of that tension, National can't seem to get it out of its own way on Covid.
Meanwhile, even if it sometimes feels as if Labour relies too heavily on a trial and error approach to managing Covid, they tend eventually to arrive at sensible decisions.
I've been particularly impressed of late with Māori Health Minister Peeni Henare, whose presence and national profile allows him to persuasively appeal to Māori values: our sense of collective responsibility; our obligations to whakapapa and whānau.
By calling on Māori to protect ourselves from Covid, Henare often cites the phrase, Tiakina te pā harakeke (protect the pith of the flax bush). In other words, we build resilience and wellbeing from the inside out.
• Shane Te Pou (Ngai Tuhoe) is a company director at Mega Ltd, a commentator and blogger and a former Labour Party activist.