Almanacs: The Oldest Guide to Everything, Radio 4Reasons to be Cheerful, Radio 4

Almanacs should have been able to predict their own demise

Today we have science, but we also have horoscopes and homeopathy and religious hysteria.

Humankind has always liked to mix fact and fiction: how else to explain the Daily Mail? In the 16th and 17th centuries they had almanacs, 400,000 of which were sold annually in their pomp. Ben Schott, of Miscellany fame, charted their super soaraway trajectory in Almanacs: The Oldest Guide to Everything – which recalled among other things the sex tips of the day: "Embrace Venus honestly" in May, but "Entertain Venus daintily" in November.

They became associated with buffoons – Bottom consults one in A Midsummer Night's Dream – but aside from the astrological claptrap, they were full of useful info such as the dates of trade fairs, law terms and rent days, tips on planting crops and how to draw up legal documents. Then there were the medical ads: "The cordial pill – the grandest, the most excellent preparation of all the opiates ever invented". And after all those Venus-related shenanigans there was always "the safest, speediest and surest cure for gonorrhoea".

Pepys liked to take the previous year's editions down the tavern with his mates and have a laugh comparing the predictions with what actually happened. And in the end, real life did for almanacs: they failed to foresee the execution of Charles I or the Restoration, not to mention the Civil War, the plague and the Great Fire of London. Rabelais parodied them: "This year the blind will not see much, the deaf will hear rather poorly, mutes will not talk much and the healthy will stay better than the sick."

Weakened by satire, undermined by bad predictions and besieged by the Enlightenment, they faded. They live on, though: printers began inserting blank pages for readers to write their own notes, and our desk and pocket diaries, full of information such as tides, lighting-up times and public holidays, are direct descendants – even if they don't dispense advice on what to do about Venus.

Venusian matters might well have figured in Douglas Kennedy's paean to the upbeat, Reasons to Be Cheerful. Part one of the new series, in which the comedian and actor attempts to convince a pessimist he's got it all wrong, didn't get round to rumpy-pumpy, concentrating instead on team sports, nanotechnology and cycling. This week's misery-guts, John O'Farrell, comic writer and Grumpy Old Men stalwart, wasn't impressed by any of them. He hated sport at school, and is a fan of Fulham FC, a singularly thankless task until recently. Don't get him started on life-extending modern technology – "Pensions time bomb," he muttered. "I miss rickets." And as for cycling, "If you think that's a reason to be cheerful ..."

The nanotechnology bit was fascinating: at University College, London, they're creating nanodiamonds, which are put in a cell culture with neurons. The nerve cells attach themselves to the diamonds, grow, connect and start to communicate. Personally, I think that might be a reason to be terrified.