I read in The Times yesterday that scientists can induce dyscalculia — number blindness — by subjecting a section of the parietal lobe to repeated transcranial magnetic stimulation. It doesn’t hurt, but over time you become innumerate, and I thought, yes, that’s what we journalists are doing right now. Whenever the voter shows any signs of getting interested in policies, we hit them with a whole load of stuff about the personalities of politicians, and gradually the ability to work out anything complicated dwindles.

This, therefore, is roughly what we have been led to think of the leading contenders to be PM in the next few years: Cameron, D. Inexperienced toff with changeable hair leading a Shadow Cabinet that looks like a night out from Brideshead Revisited, but who — Hugh Grant fashion — understands where to find the collective political G-spot of Britain’s women; young and fresh. Campbell, M. Decent but past-it old git with a prostate problem; ancient but game. Miliband D. Bright-eyed geek with hair, sexual magnetism untested; young but unknown.

Brown, G. needs a bit more space because we think we understand him better. Dour, Presbyterian, nail-biting, ambitious amalgam of Stalin and Macavity. (Incidentally this is an unlikely combination, as evidenced by what happens when you substitute “Stalin” for “Macavity” in T.S. Eliot’s poem. “He always has an alibi, and one or two to spare/ At whatever time the deed took place — Stalin wasn’t there”, doesn’t quite work because the whole point of Stalin was that he was always there.)

If all this was a useful guide to how the contenders for high office may carry out the duties of prime minister, then such a concentration on personality might be justified. But it isn’t. There was the case of the graphologist brought in by the Tories to analyse Gordon Brown’s handwriting, and who decided that he was a borderline murderer because he capitalised everything. What she wasn’t told was that the Chancellor has very little sight in one eye. And nor were the readers.

These are just a series of fantasies people have about what these guys are like. We don’t know if they’re true, though we could speculate about them for ever. So it seems far more sensible to me to ask not “Who?” but “What?” What would they do if they were PM? And that’s the thing that we really don’t know.

It is hard to focus. Lost in the current orgy of self-indulgent catastrophism and victimhood by proxy (as in “this country is becoming a fascist state — why only last week a parking warden . . .”), is any sense of how Britain has actually changed in the past ten to twenty years. There is little media or popular memory of mass unemployment, flu crises or of what Gerry Adams might have tried to do to Ian Paisley if he’d met him face to face in 1987.

The truth that no politician should expect to be appreciated was repeated by Mr Miliband in an article at the weekend. “Politics is about ideas for the future, not gratitude for the past,” he wrote, before arguing that some new Labour thinking was “too mild, too imbued with a spirit of continuity rather than animated by an impulse of change”. Hirsute geekboy had that one right.

Let me illustrate this with two items from yesterday’s news. One was the extra demand for maternity and abortion services arising from the huge number of young East Europeans (mostly Poles) who have come here to work since 2004. The other was the increased demand for maternity nurses on the part of well-off career women who had become mothers quite late in life. “Health visitors won’t come out at 3am,” said one woman. You betcha.

Sections of the electorate and of all three main parties want to tailor policies to cope somehow with the present tidal wave of endogenous grumpiness and misplaced nostalgia. But much of that ill-humour may be caused by the speed with which the world is changing. The need to be a great worker, a wonderful parent, possess a lean body and keep up with the latest technology is exhausting. I should know.

The world won’t stop, so it is sensible to ask which putative prime minister and which ideas are likely to cope with what is ahead, rather than what has just gone. At the moment we simply don’t know. Mr Cameron is still in the throes of rebranding, of enthusiastically showing what his party isn’t, and some odd positions are being taken as a result. One consequence was yesterday’s audacious, enjoyable and almost unhinged attack by the former minister Denis MacShane on the new Conservative party for being too old Labour. Why would the Shadow Chancellor say that the Tories were “the party of the public sector”, bellowed Mr MacShane, when any fool could see that the future lay in root-and-branch reform of that sector, and not in defending vested interests? It’s certainly true that the current Cameronian campaign on the NHS is fundamentally defensive, and offers no clue as to how Charles and Sebastian intend to pay for vastly increasing personal health demands. It is also true that sections of the Labour Party who think in exactly the same way seem to imagine that they — not Mr MacShane — represent the party’s future.

In his own article Mr Miliband spoke about how Britain needed to move beyond paternalism, to “break down the divide in public services between producer and consumer . . . to make creativity the driving force of the education system . . . People want to make a difference by taking decisions for themselves and with others.” But what does this actually mean? The Labour ministers James Purnell and Jim Murphy made a few suggestions on this page yesterday. There was a possible pilot for giving pupils a bit of money to develop their talents, which sounded nice, but a bit marginal — more like a programme idea for Channel 4 than a strategy.

Look ahead. I think that the idea that there is still a separate ethos for public and for private sectors should now be discarded as a piece of history. Parties need to start doing some difficult talking about a widespread system of co-payment in public services covering discretionary areas such as GP appointments. They need to consider introducing education vouchers for children in failing schools that would also to be redeemable in private schools that want to keep their charitable status.

You get the idea. And it’s dealing with this stuff, not Gordon’s teeth, David’s parting and Ming’s virility, that should tell us who to back for the top job.

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