Trying to summon a view on Theresa May’s grammar schools feels pointless. It’s not that I don’t believe she’ll do it, since if there’s one thing this party has proved beyond doubt, it’s its determination to enact ideas about which I initially assumed it was joking. It’s not that I don’t think grammar schools are an appalling idea, nor that I don’t mind when a prime minister ignores reason and evidence in favour of cant and nostalgia.

Rather, it’s the knowledge that this conversation isn’t about education, it’s just a badge that says: “I believe in grammar schools because I’m a one-nation Conservative. Broadly, I think things were better in the olden days, when a grammar school could lift a child from a life of circus drudgery and anoint him prime minister, and I’m prepared to overlook the fact that the grammar school of this parable actually supplied John Major with no more than three O-levels and today would be in special measures. The fact that grammar schools don’t deliver meaningful mobility is less important than what it says about me that I believe in them.”

This is comfort-blanket politics, with debating points as familiar as the seasons. It is a reassuring balm to the faithful, and a closed conversation to which unbelievers aren’t invited.

There’s a similar impetus behind Labour leadership contender Owen Smith’s promise to end the tax breaks private schools enjoy because of their charitable status. This is the classic identifier of the reformer who doesn’t intend to frighten any horses: “I’m not against private education per se. I just don’t think it’s strictly speaking third sector work, to hive off the children of the rich, the better to endow them with a sense of entitlement. I’m not sure this is what charity is supposed to be all about. Correct me if I’m wrong! I’m a reasonable man.”

The reassurance is textured: Smith’s is no simple rejection of elitism, but rather, a promise to tackle privilege in the most modest, incremental and – fundamentally – unarguable way.

Contrast the intentions of Michael Gove, in his time as education secretary. It seems ever plainer, with more distance, that Gove was trying to transmute the UK’s academy system into a wholesale mimicry of American charter schools: local governance was inherently complacent, unions were the enemy, the pillars of decent education were defined by people who thought it could be counted in units.

It was inevitable that, once the people with experience and expertise were sidelined, corruption and incompetence would sneak in. It was only to be expected that teacher morale would be bled dry – the new thinking painted the entire profession as an enemy of ambition.

You can say what you like about all this – I think it’s one of the most destructive things the Conservatives have done, against some awe-inspiring competition – but there was nothing soothing about it. Its platitudes were a mask for radicalism rather than an end in themselves. Gove’s job, which he did magnificently well, was always to hide how revolutionary it was. Any progressive force against that has to marshal the same energy.

This is why Jeremy Corbyn’s proposed national education service, even while its Maoist overtones are so strong, is so impressive. It starts with a principle that sounds like common sense: education is a public good. Learning should be provided from cradle to grave, as health is. An ambitious and courageous state knows the wealth of the nation is in its people.

An ambitious and courageous state knows that the wealth of the nation is in its people

From there, it goes to universal free childcare, an idea that all parties have periodically attached themselves to, and a classic New Labour manoeuvre, where any thought deemed too redistributive found broad acceptability wrapped in a nappy: hence Sure Start, the child trust fund, the child poverty target.

Next, Corbyn pledges decent schools for all, including class sizes of under 30, an idea so universal that the only question it raises is why it’s not already the case. Even free tertiary education, the idea with the leftiest pedigree, does not go against established thinking. The status of tuition fees as the natural order of things is very recent: it’s not long at all since Nick Clegg believed in free universities. It was, astonishingly, only 2003 when Iain Duncan Smith called Tony Blair’s hike of tuition fees to £3,000 a “tax on learning”.

Free tertiary education is also the issue on which progressive movements in Europe have had the most striking success; and in this Corbyn echoes Blair’s breakthrough on the NHS in 2000, when he argued to increase health spending, not because he loved waste, but because if they could afford a higher per capita spend in Europe, why couldn’t we?

It’s a terribly elegant argument, marrying social generosity with a pride in British exceptionalism, which must have something for pretty much everyone. Once you’ve accepted that, the promise of maintenance grants sounds like a detail. Finally, the promise of investment in adult education is a platitude – who could possibly want adults to be less skilled, less fulfilled, than they could be? – that masks a huge shift in priorities. Further education, known in the political class as what happens to other people’s children, has been underfunded for nearly a decade.

FE colleges have been appropriated to become ill-starred academies, and places on English and literacy courses for adults have been slashed. To reverse this would be life-changing for the least privileged: and yet it arrives as a very anodyne notion, that learning should be lifelong, an idea from neither the left nor the right, but the civilised mind.

It will naturally be met with a critique of its affordability, but here the Conservatives have set new mood music that they may live to find rather grating: they have never approached education through an economic lens, never paraded academies as a saving, never brooked any interrogation over how much their reforms cost. Even tuition fees were sold as a fairness issue – why should the bin man pay for the accountant’s daughter to study classics? – rather than austerity. It will be a move of pleasing jujitsu if Labour can use this lofty language to create a new normal.

More bolstering, though, would be a new phase of thinking. I hold out very little hope it will heal the rifts of the party, and am no better persuaded that the existing Labour MPs have to be vanquished rather than included. But as thinking, it is far more interesting than the rather lackadaisical cushion-plumping going on elsewhere.