Science only can go so far - and then ethics must take over.
Translating evidence into policy is done through the filter of discussion of moral implications - or should be in an enlightened state.
How far can we trust scientists with morality? Perhaps it depends on the scientist.
Sir David King, the Merlin to Blair-Brown's Arthur (er, maybe there's something wrong with that analogy), is widely credited with helping to persuade Arthur, er, Blair/Brown that new nuclear power is a good idea.
But here he is today, on the eve of his disrobing of the mantle of Merlin - finishing his stint as Chief Government Scientist - not only complaining that GM crops aren't being grown enough since they'll solve the world's hunger problems in a water-scarce future, but that Blair didn't push for nuclear power fast enough.
He says this is a moral issue.
He did, rightly, say that climate change is a far greater threat to the world than international terrorism.
He told the BBC: "What I have learnt is one can have good scientific advice, and then the decisions are of course made by the politicians; and the politicians have to take a range of factors into account."
Is it moral that the owners of seeds used by families and communities for hundreds of years should be forced to buy seeds with a terminator gene in them every year, owned by a multinational corporation far away?
Is it moral that because nuclear power seems a quick fix solution (a few large plants compared to thousands of distributed renewable plants, plus energy efficiency), life for thousands of years in the future should have to suffer the legacy of our nuclear waste?
He says throughout the interview: "I still feel a sense of frustration about the way government operates where science could contribute to science making."
The Low Carbon Kid says "I feel a sense of frustration that scientists and politicians, having looked at the science and immediate concerns, don't take a much broader perspective."
To switch metaphors, I don't know who the next Dr Who - Chief Government Scientist - will be, but I hope he combines King's astuteness with a wider imaginative and moral vision.