For practical purposes the last word on "nature" was uttered by John Stuart Mill in his essay of that name 140 years ago. Mill demolished the tendency to believe that what is natural is good by pointing out that few torturers inflict as much pain as nature unthinkingly does on millions of the sick and dying.
As to the view that we must - as Prince Charles has it - work with nature rather than against her, the answer is that we have no choice. Human action uses some of the forces of nature to control or thwart others of those forces. Rationality is a matter of doing so in ways that - within the limits of human foresight - don't come back to plague us.
So the ethics of policy-making are interesting in a quiet sort of way. Given the uncontroversial thought that governments should secure the general welfare on fair terms, while respecting the human rights of the citizenry, most policy issues are instrumental, and most difficult questions are factual.
But some ethical issues are certainly more than instrumental - transparency and openness not only make for good policy and bring the public along with that policy, they also embody the moral view that a grown-up public must be treated as such.
And there are concepts, such as "the precautionary principle", that badly need rethinking. If it means we may never do anything that might go wrong, we'd never get the car out of the garage. If it only means we ought to be careful, it has no bite - nobody ever advocates thoughtlessly blundering ahead. Somewhere in between lies good sense.
GM crops have replaced paedophilia as the focus for public panic. Thus far, neither Government, nor press, nor the consumer and environmental lobby has emerged with credit.
The incapacity of most discussants to stick to one issue at a time has been impressive, but gloom-inducing. Friends of the Earth's, the Consumers' Association's and Greenpeace's style has moved from "it might damage your health" via "it might kill ladybirds" through "Monsanto is a nasty monopoly" to "we need to know what we're eating" and then back again.
No anxiety can be laid to rest, as the stirrers-up change the question as soon as it shows signs of being answered - confusing every issue.
But there are four truths worth noting. First, the idea that we should only allow people to produce what there is a real need for, is dotty. If every inventor had to show a need for what they'd invented, we'd be using packhorses and walking, and our life expectancy would be about 35. GM crops so far are dispensable, though they have saved farmers money in the US and have probably been good for the land by reducing ploughing.
Second, the environmental damage done by industrialised farming should be tackled by rebuilding the subsidy regime - Europe's Common Agricultural Policy is the target, not GM crops.
Third, too much theology is about: the Soil Association was created by upper-class ladies in the 1900s as an affiliate of spiritualism, and its adherents behave like a religious sect today: calling a small amount of possible cross-breeding "pollution" is just as superstitious.
Fourth, consumers certainly ought to know what they are eating: when they were offered GM tomato paste that was less watery and cheaper, they bought it. Monsanto may or may not be greedy, but, if its managers are rational, they won't destroy the business by poisoning the customer - hundreds of millions of whom have been eating GM soya for several years - or by producing seeds that have no advantages over those from conventional breeders.
But it is unlikely commercial interest alone will drive research in the direction of what would do the environment most good - fixing nitrogen in the roots of cereals, for instance. It is an irony of Government policy that there are now almost no much-needed, public plant-breeding facilities.
And the public - the victim of Guardian mendaciousness as much as Daily Mail and Express silliness - has been let down by people who ought to know better.
The writer is Warden of New College, Oxford