Here's another answer, given by an elderly taxi-driver who listens all day to Radio 5 in his cab: "Dunno, love. Is it music? Only, I hate music."
If you treasure Radio Four and switch on whenever there's a boring job to be done, when you get into a car or a bath or a fit of the glooms, you might find it hard to imagine that there are people out there - people who've found Radio Five, for goodness sake - who don't even know about it.
James Boyle is all too aware of this ignorance. Eight million people listen to his network each week, though half of those only give it 15 minutes. That leaves about 50 million who don't. He'd like to get some of them in.
One of the problems is that people's timetables have become so varied. When the Home Service started, in the good old days before television, it was a fair bet that mothers would be at home ironing along to Woman's Hour every afternoon, and that children would develop a Neighbours-style addiction to Children's Hour - the mere mention of which still stirs the most hardened old buffers into dewy nostalgia. Today, most people listen from 6.30 until 8.45 am, then switch on and off again at lunchtime, and then on and off for The Archers.
What this suggests to Boyle is that the popular Today programme should be extended backwards to 6am, leaving a scant pre-dawn 10 minutes - scarcely time for more than the fatstock prices - for Farming Today. He says that farmers don't listen to it much, that its main appeal is to urban people who like to feel that they are being kept in touch with the countryside. Yet isn't that surely one of the main attractions of Ambridge? And is it not possible, at least, that the larger 6.30am audience won't in fact be awake to hear the start of an earlier Today?
Such arguments present themselves all through the changes that Boyle announced on Wednesday. Another anomaly is his intention to keep Melvyn Bragg but to change the format of Start the Week, cutting out the spontaneous spats. The enjoyable rumour that Melvyn would be interviewing the stars of EastEnders proves to be unfounded: it will be "Nobel prize-winners", we are told - if they can find enough of them. Still, it is hard to believe that the presenter is more popular than the often stimulating arguments that characterise his show.
James Boyle compares the current schedule to a medieval town-plan, and it is easy to see what he means. Historical precedent has decreed that the programmes are of unequal length, and that some have traditional and often unsuitable time-slots.
Yesterday in Parliament is, understandably enough, a literal turn-off (though it should be said that those who sieve the gold from the dross of Westminster do heroic work). The World Service works to a strict and orderly timetable of 15-, 30- and 60-minute programmes, and it is indeed easier to find your way into it when drifting around the dial. It is high time for rationalisation.
So, from next April, we shall become accustomed to similar regularity on R4 - and of course we can do it, and of course it's not a bad thing to tidy it up. It will be nice to know, for example, that we can rely on hearing new drama every afternoon at 2.15. But medieval towns have an appeal that Milton Keynes can never achieve. It's fine to have the access improved and the landmarks clearly labelled, but it's also important to keep the half-timbered buildings which, however impractical, are a lot more attractive than multi-storey car parks.
The dozen or so edifices due to be bulldozed might, indeed, be due for redevelopment. Many of them seem likely to be reconsti- tuted in some new form, and it becomes a matter of personal taste as to which will most be missed. Kaleidoscope, The Afternoon Shift and Mediumwave all needed rethinking, but I am sad that children's radio is finally to be stifled, and sorry to lose some quirky little numbers like On This Day and Ad Lib, while rather dreading the thought of an extended You and Yours.
But the delight, as well as the devil, may yet live in the detail. The broad outlines are fine: it remains to be seen whether or not the interior designers can live up to the ambitions of the architect.