What happens when we die? That was the big question asked by Paul Heiney late last Sunday on Believe it or Not (R2). He had assembled three believers to answer him: to everyone's credit, they did their very best.

Angela Wood, speaking for Judaism, was the vaguest. Jews say there is a "something" - but it could be physical resurrection, or reincarnation, or even just a lingering memory in the minds of the living. Nicholas Coote, for the Roman Catholics, was the most profound, speaking of a mystical union with God as the consummation most devoutly to be wished. Angela Tilby, for the Church of England, was the most accessible. She said that we all have a deep homesickness within us, a longing for eternity - and she mentioned a common experience, a moment when time had suddenly seemed to stand still for her, when she had glimpsed perfection.

This is a remarkable series. It is rare to hear such enormous issues tackled so frankly yet so briskly. Heiney moved steadily through Dante's agenda, lingering in Purgatory, noting the probable emptiness of Hell, advancing to the sublime ecstasy of Heaven - and drawing in other religions and supernatural experiences on the way. Best of all, he dared to take seriously the possibility of the existence of the soul, and of the Incarnation which we are all, in various ways, about to celebrate. Only the rather naff music let it down. Heiney is married to Libby Purvis, whose R4 series about Christianity, Mysterious Ways, ended strongly this week: there must have been some pretty serious conversation in their house lately.

When you consider A Miracle in No Man's Land (R4), you probably think of the Christmas truce of 1914. But Alex Jones's play was set in December 1917. He himself played Joe Taylor, a man who walked out of battle claiming to have seen a vision of Christ. Expecting to be shot as a deserter, Taylor won a reprieve because the army didn't want a martyr - but then he toppled the argument and admitted that he had made the whole thing up, having simply fought through one battle too many. The miracle was that it worked. This was a splendid play, complex and intelligent: its sinuous plot kept you breathless until the very end.

And spirits haunted another play this week. Dante Gabriel Rosetti may well have been Clever as Paint (R4) but, in Kim Morrissey's view, he was a pig. William Morris, here depicted as a cuddly toy, tried ineffectually to help poor Lizzie Siddal, Rosetti's muse, model and tremendously ill- treated wife (well-played by Imogen Stubbs). Alas, she suffered his abuse, died of an overdose of laudanum and was buried with his poems. When he couldn't quite remember the one to his mistress - and got someone to dig up the book - Lizzie came howling back, most satisfactorily, to haunt him.

On Tuesday afternoon I thought I'd found yet another session with the supernatural, catching these few words: "a soul is easily overlooked ... it ascends from obscurity to glory ... order up your soul with pride." But no, it was fishier than that. Filet de Sole Veronique (R4) told a gloriously barmy story about the invention of this famous dish, in Paris at the end of the last century. Delicious.

That sly pun is the kind of thing to delight Bill Bryson, whose series Mother Tongue is custom-built to irritate R4 listeners, a race of purists and pedants. As a paid-up member, I must express outrage at his invitation to an expert to read the two most famous bits of Eng Lit as they might have been pronounced. This man was no Olivier. His rendition of "To be or not to be" made little sense, while Chaucer's Prologue to the Canterbury Tales was actually misquoted (and Aprille, in Middle English, has to have three syllables: only think of "I sing of a mayden", and you'll see what I mean).

Enough nit-picking. Bryson's genial enthusiasm eventually dissipated my rage - and his journey through the years of the Great Vowel Shift and out to the colonies was highly entertaining. Long before English even twinkled in the eye of Beowulf, writing was invented in a place often thought to have been the site of the Garden of Eden, in other words between the Tigris and the Euphrates. The World Service's huge new series Civilisation began there, in Mesopotamia - or Iraq. It's very good - thorough, steady and scholarly, though not always exactly PC. I mean, who's to say that the "blazing genius" who first wrote the sounds of words on clay tablets was a man? Wasn't society in the fifth millennium BC generally matriarchal?

Let's leave the nits and lower the tone. Ads R Us (R2), introduced by Lorraine Chase, surveyed the phenomenon of television advertising. Chase whistled through the Murraymints and the fruit gums quite cheerfully, before settling down to interview the worthy Henry Cooper, who really did wear Brut and believes you should always endorse the product you advertise. Harry Enfield is the opposite. He'd do just about anything for money, he said - but he must be tough to work with, insisting on rewriting all the little playlets created by the advertisers. No shrinking violet, he used this programme to promote himself: "The sales of the things I advertise are really very good and I couldn't recommend highly enough that advertisers use me." I suppose the BBC charter doesn't frown on self-advertisement.

Finally, back to hauntings and a new series in which Ian Burnside visits Literary Houses (R4). He began with Max Gate, the last home of Thomas Hardy. Hardy's gloomy spirit hovered over the tour, despite Burnside's refreshing disrespect. A programme like this is seldom exactly fair, but it does present a new angle on celebrity. "This looks to me awfully like a loo," said Burnside, flushing to learn that the wretched gardener had to pump the water up to it 200 times daily, more if there were visitors. Hardy fancied a woman called Agatha and took up cycling with her. His first wife, Emma, joined in and now the Bicycle Room houses her bike, mysteriously named the Grasshopper. Finally came the chilling story of Emma's lonely death in a tiny attic room and the discovery of her notebooks, entitled "What I think of my husband". He burnt them, but that didn't help. None of us thought much of him by then.