Last Night's TV: Inside the Medieval Mind, BBC4<br />Sex, Lies and the Murder of Mereditch Kercher, CHANNEL 4

If you believe the camera on Inside the Medieval Mind, life in the Middle Ages was a weird and scary trip: the invisible men shimmering around the place, the dog-headed people lurking in the shadows, the women in glowing white robes popping up behind you when you're trying to play chess with your doppelgänger. The Renaissance must have come as such a relief.

I don't believe the Middle Ages felt like that at all; actually, life probably was scary, but in banal ways. Most people were too worried about hunger, cold, disease, the fact that everything was damp and smelled funny, wild things making noises in the dark, and the prospect of being beaten or maimed by their fellow human beings to give much thought to dog men. Still, it's not often that my main problem with a television programme is that it's too interesting, and I'm prepared to overlook the colourised, glossy look inflicted on the scenery on the grounds that they've left Professor Robert Bartlett alone. He is a large man who looms at the camera, and he is, if not dishevelled, not exactly shevelled. He projects a reassuring impression of a man who's been asked to do this because he knows about it and has interesting things to say.

The theme of this programme was the emergence of rational thinking from a world of superstition. The thing that distinguishes our minds from medieval ones is that we are more likely to ask questions and look for evidence. In the Middles Ages, knowledge was, essentially, received. If it was in the Bible, it had to be true; and if you heard stories of green children emerging in Suffolk from a marvellous underground country, of wild fish men being caught at sea, of far, distant regions inhabited by men with faces in their chests or giant feet they could use as umbrellas, well, given that you hadn't heard any different, you might as well take those to be true. Professor Bartlett quoted a report by the abbot Ralph of Coggeshall, about the netting of a fish man, who refused to utter a sound, even when hung upside down and tortured for information. For Bartlett, what was disturbing here was that Ralph worried less about whether the story he'd heard was true, than about what category this creature fell into (did it have a soul? In which case, ought it be converted to Christianity?). For me, what was disturbing was the casual mention of torture as a means of extracting information. Didn't they even have the decency to pack them off to a friendly power to get the torturing done?

There was quite a lot of entertainment in this vain: stories about people chucking spears and arrows at the moon during an eclipse, or about beavers, who would fool the huntsmen after them for their scent glands by biting off their own testicles, then cocking a leg to show off the blank space. Similarly, medieval bestiarists pointed out, we should be biting off our own vices, so that the Devil can see there's no point hunting us. Why doesn't David Attenborough give us useful stuff like that?

Sadly, all this picturesque counter-knowledge was being slowly picked apart by advances in thinking: Thomas Aquinas promoted reason, so long as it was compatible with the Bible (Bartlett got in a good story about his parents trying to dissuade him from the clergy by locking him up and sending in nubile young women); Roger Bacon promoted experience as the measure of knowledge; the conquest of Moorish Spain gave Western Europe possession of Aristotle's philosophy, as well as Arabic numerals – so much easier to calculate with. Meanwhile, travellers such as Marco Polo were establishing that the Eastern fringes of the known world were not inhabited by dog-heads – in fact, the Easterners assumed that the dog-heads all lived in the West. Occasionally, Bartlett left gaps that needed filling. His account of the invention of the mechanical clock implied an impressive industrial-technical infrastructure, with metalworkers who could make complicated and precise components. Clearly, there was something he wasn't telling us. But there are another three hours to go, and I'm looking forward to looking back.

Just in case you were getting all smug about our rational, evidence-based thinking, Channel 4 had Sex, Lies, and the Murder of Meredith Kercher, a Cutting Edge film about the British student who was killed in apparently scandalous circumstances in Perugia, Italy, last November. Peter Bate's documentary made it clear that the real scandal here was the eagerness of the police and the media to propagate unsubstantiated theories about drug-fuelled orgies and sexual violence, though the film itself wasn't altogether untainted by prurience or speculation. In fact, the guilt of Amanda Knox and her boyfriend, Raffaele Sollecito, treated as fact at the time, is far from established. They and a third suspect, Rudy Guede, have been in jail for five months without being charged. It makes a 90-day limit seem quite moderate.