But Supernatural (BBC1) takes things too far. In its attempts to show life through animals' eyes, this series resorts to special effects to an unprecedented degree - computer- generated birds flap across videoed landscapes, moons whizz through night skies, people plod about their business in slow motion. This superabundance of trickery gets irritating.
What's even more annoying, though, is the programme's obsessive urge to find a visual equivalent for every sentence, to convert every idea into narrative. Last night, during a discussion of bird navigation, we heard that pelicans need to locate the best fishing grounds, "like trawlermen": and even as the word was spoken, a couple of trawlers hove into view, and suddenly we were plunged into an underwater maelstrom of beaks, nets and glistening fishes. Also, a perfectly helpful compar-ison between the static electricity generated by a snake and that generated by synthetic clothing was illustrated by a ludicrous sketch about a confrontation between a couple of Lycra-clad cyclists and a rattler.
All this is supposed to make the strangeness of an animal's world more vivid. But none of it is half as forceful as the philosopher Daniel Dennett's attempt to convey how a dog sees things: a bird flying overhead may come across as nothing more definite than the sky going all "birdish" for a while. If Supernatural could convey the notion of birdishness, it would be getting somewhere.
There was more faked up narrative in Great Expectations (BBC2), where Tony Marchant, feeling that Dickens had left out some important stuff, put it back in: Pip, conscious of his ingratitude to Joe Gargery since he became a gentleman, offers to help him out in the forge, but Joe tells him it wouldn't be fitting; Pip tells his dying benefactor Magwitch that he regards him as his father and loves him; and Pip declares his suit to Biddy. Of course, the adaptor has to invent, and some of Marchant's inventions were admirable - Pip reciting Homer to Magwitch in the original Greek, offering consolation through the sentiments and through the proof that he is now a gentleman; and a new ending, in which Pip and Estella play cards together that was more in keeping with the original than the curtain-ripping of David Lean's film.
But the other changes I mention altered and blunted the morals and emotions behind the story. Classics are usually classics for a reason; you need a good reason to mess around with them. So, finally, this version left me unhappy. Not surprising, really: in the nature of things, great expectations tend to finish in great disappointments.