IN 1929, the Roman Catholic priest and crime novelist Ronald Knox set out his ten commandments for writing detective fiction. They are a peculiar mix of the practical and the prejudiced: there is an injunction against the inclusion of identical twins or Doppelgängers, and the use of more than one secret passage per novel is ruled out. And commandment five is: "No Chinaman must figure in the story."

I am not sure how many Chinese men appear in James Runcie's Grantchester mysteries; but, in Lent Talk (Radio 4, Wednesday of last week), he reassured us that he kept the other commandments as best he could. Crime fiction is a genre that comes with many strictures, but Runcie's attraction to the form derives from the opportunity for examining characters under pressure. The world that he creates might seem cosy; but, under that cosy, "the pot may be scalding, and the tea poisoned."

This was a splendid start to the seasonal strand, but I could not quite make the leap that Runcie invited us to take, from 20th- century detective fiction to medieval Mystery plays, and then to the story of the Passion. Indeed, the Passion story, as Runcie demonstrated, is a mish-mash of genres: heist movie, courtroom drama, and with a "Tarantino-style" finale. Crucially, the story breaks Knox's second rule: "All supernatural or preternatural agencies are ruled out as a matter of course." The mystery of the resurrection remains a mystery.

If you want a terrifying insight into the future of social interaction, listen on the BBC iPlayer to Analysis: Artificial Intelligence (Radio 4, Monday of last week), which featured a conversation between the presenter, Helena Merriman, and a "chatbot". After no more than three exchanges, the AI stopped attempting coherence in its answers, and closed down the conversation with a stroppy retort. In as much as it replicated the kind of conversations that take place after 30 years of marriage, it might be considered realistic; but, as a guide to the computer's abilities, it seems that AI has a long way to go.

More revealing than the progress science has made in the field was the fact that so many people appear to be excited about the prospect of a computer simulating brain function. Professors from institutions with names such as the Future of Humanity Institute talked with enthusiasm about how many teraflops of data one of these things could process in one second; and how our brains, which had evolved in a prehistoric environment, needed help with an information-heavy world. Hunting and gathering is so last aeon; now you can order a takeaway with the stroke of an app.

Recycled Radio (Radio 4, Wednesdays) is a show that sounds as if it has been put together by an AI. This collage of radio tit-bits feels as if it has been sourced via some sophisticated Google search, and then assembled in an instant by a computer programmed to maximise sardonic humour. The juxtaposition of Melvyn Bragg, Jenni Murray, John Humphrys, and other familiar voices is amusing for about three minutes; but then one longs for an authorial voice. Gerald Scarfe was promised by the blurb, but he hardly featured.