Please could politicians stop referring to "the science" which guides our understanding of coronavirus?
We all know that there is no such thing as a single, universally agreed scientific viewpoint on this new disease, never has been, and possibly never will be.
What we have instead - and, believe it or not, this is a good thing - is a broad range of opinions based on theoretical modelling (educated guesswork, which is of limited use) and the gradual emergence of verifiable medical evidence (which is much more informative and reliable).
Disagreement and dispute between scientists is beneficial, indeed it's essential, because this is precisely how science progresses: through testing hypotheses, interpreting data, scrutinising research. Anyone who behaves as though the science of Covid is settled, definite and absolute is in danger of turning science into religion: a matter of moral belief, not established fact.
Take the question of face masks. Having informed everyone that masks were not especially useful in controlling corona, Boris Johnson's government has now belatedly decided, at the tail end of the pandemic, to force shoppers in England to wear face coverings, under threat of a £100 fine.
Here in Northern Ireland, the Infrastructure Minister Nichola Mallon is keen for Stormont to bring in the same rule. We already have mandatory mask-wearing on public transport. Her argument is that if "the science" - yes, there's that bogus phrase again - supports mask use on public transport, then they should also be worn in shops. Health Minister Robin Swann agrees, and is reportedly preparing to bring a proposal to the Executive.
So do masks or face coverings make a significant difference to the spread of Covid? Nobody knows for sure.
Many scientists and clinicians, such as the president of the Royal society, Sir Venki Ramakrishnan, believe that masks are important. The World Health Organisation recommends their use in public. Even to lay-people like the rest of us, it sounds like common sense: covering your nose and mouth in order to avoid spraying potentially bug-ridden droplets over the person sitting beside you on the bus, or standing in the checkout queue.
But like everything corona-related, it's not that simple. There is a difference, for instance, between high-grade, fitted surgical masks, used by professionals, and the common-or-garden cloth ones that most people use and re-use without disinfecting them. The existing evidence for cloth masks is of limited quality. Indeed, some distinguished scientists think that they may even do more harm than good, by becoming a sort of portable petri dish for germs.
Professor Carl Heneghan of the Centre for Evidence-Based Medicine at Oxford University, is emphatic: "Let's be clear, the high quality trial evidence for cloth masks suggests they increase your rate of reinfection." Prof Heneghan says that if masks are going to be mandatory, they must be disposable ones - but he points out that this will bring a new inequality to society, because so many less-well-off people cannot afford them.
So will the government provide free masks to people on low incomes? How do Robin Swann and Nichola Mallon propose to address such an inequality, here in one of the most impoverished parts of western Europe?
And then there's the fact that science itself is not immune from politics. This week, BBC Newsnight's health correspondent, Deborah Cohen, reported that the World Health Organisation committee, which reviewed the evidence for face coverings in public, did not advocate their use. But after political lobbying, the WHO now recommends them. Coincidence? Clearly, Cohen thinks not.
The sudden push for mask-wearing is, in my view, far less about protecting public health than about governments being seen to take action in the face of high levels of public anxiety.
So why not be upfront about it?
Why not say: 'right, for the next two months, we're going to ask everyone to wear disposable masks, which we will provide free of charge, when they go into shops or on public transport. It may or may not make much difference to the spread of Covid, but it will help worried or vulnerable people feel more comfortable about going out again.'
I don't enjoy the claustrophobic sensation of wearing a mask, and I don't feel it's necessary for my personal protection because I'm not in a vulnerable category. But I would be willing to sign up to such a plan, on a temporary basis, if it helped to restore confidence in others.
Appealing to people's sense of social responsibility - amply demonstrated during the pandemic - is a far better approach than force, diktat and the threat of fines.
Instead of hiding behind "the science", whatever that's supposed to mean, politicians should trust people with the truth.