How should journalists and programme-makers report contentious scientific debates? Traditionally, the answer is to seek to be impartial.
What does that mean? Well, if a news report or a documentary is impartial, then, for one thing, it includes opposing points of view.
But what subjects require the inclusion of opposing views? Not simply those, surely, on which opposing views exist: we don't seek out flat-earthers every time we refer to flying around the world.
Would a subject's being 'controversial' define the need for this kind of impartiality? Or, to put the same thing negatively, are balancing views required when there is no consensus?
Well, maybe. But this is where Professor Brian Cox feels broadcasters have sometimes gone wrong.
Giving the Hugh Wheldon Lecture on BBC2 on Wednesday, he argued that, in the context of science, impartiality should mean finding a balancing view when what is being said runs counter to the scientific consensus. Not simply when it is a subject on which public opinion is divided.
So, for instance, the safety of MMR vaccines was accepted by doctors, and therefore was not 'controversial' by the criterion he would want used. But broadcasters persisted in suggesting it was, and included the mavericks who thought otherwise in the name of impartiality.
Similarly, when he referred to astrology in one of his programmes as "a load of rubbish", he wasn't happy with a BBC statement to offended astrologers which said he was expressing a personal opinion. The scientific consensus was on his side.
Fearlessly, in his lecture, he waded into the same debate again, referring to those who had complained as "the irrational community".
He isn't against polemic in scientific matters, and defended the right of those behind Channel 4's The Great Global Warming Swindle (which he described as "total bollocks") to put their point of view - so long as the programme had been clearly labelled in a way that left viewers in no doubt it wasn't to be viewed like a traditional Horizon.
Cox's hero is Carl Sagan, whose Cosmos series in 1981 was a formative influence. And not only, it seems, on his passion for science. Sagan, as we saw from clips, had a complicated dress sense: an orange anorak over a white shirt and tie for his final piece to camera.
Cox gave his lecture in a T-shirt beneath a smart pin-striped suit jacket. When it comes to choosing between formal and casual, great TV science gurus need to know how to display sartorial impartiality.
