James Wilson would have been bewildered and horrified to learn that 150 years later Britain is credited in the Irish folk memory - and general liberal opinion - with callously allowing a million people to starve to death; at the extreme end of the spectrum, in the ghettos of West Belfast and the dumber reaches of Irish-America, she is accused of genocide. He would have been incredulous, also, to hear that a British prime minister has sent to a famine commemoration event a message that says, inter alia: "Those who governed in London at the time failed their people through standing by while a crop failure turned into a massive human tragedy."
Admittedly, Tony Blair's statement last Sunday was cautiously worded. He did not in fact apologise, for that implies retrospective responsibility, but he sadly noted the failure of his government's predecessors. Had New Labour been in power in the 1840s, we infer, everything would have been different: efficiency tempered with humanity would have sorted the problem out.
Mr Blair is too sanguine. Even in these days of instant communications, fast transport and international co-operation, the developed world has still found no way of eradicating famine. The heart directs that immediate needs be met; the head fears worse long-term suffering if peoples give up self-reliance in favour of aid-dependency.
The debate has altered little from that which divided Westminster politicians 150 years ago. The Tory government, under Sir Robert Peel, used its heart, provided cheap food, set up public works and was accused by Whigs such as James Wilson of inviting disaster by giving way to dangerous sentimentality. The Whigs saw the protectionist Corn Laws as having been a major cause of the famine, and enthusiastically supported Peel in bringing about their abolition.
The consequent split in the Tory Party brought the Whigs into office in June 1846, determined on hard-headedness, but confident that a free market in corn would resolve the problem of food shortages. They were not expecting that the potato crop would fall again, and when it did, they had no idea what to do.
On the one hand were the free-market ideologues who believed utterly that government interference was malign: "irremedial ruin and degradation" would follow, explained Wilson, should Ireland not be left to her own devices. What was wrong in principle had to be wrong in practice: "The science which serves only to navigate a ship in fine weather, and is inapplicable in a storm, is unworthy of the name." Yet his friend Lord Clarendon, then President of the Board of Trade and later Lord Lieutenant of Ireland - normally a stout proponent of laissez faire - defended the Whig government's feeble efforts to provide some temporary remedies: "you in fact say do nothing, which is exceedingly comfortable for a gentleman writing by his fireside in London, but not at all practicable for a government having to answer to the humanity and generosity of England for the mortality of Ireland."
The disaster that between 1845 and 1851 caused a million deaths and led about one and a half million people to emigrate was largely a result of desperately bad luck. The population had doubled over the previous half- century; dependence on the potato - the staple food of half the Irish people - was greater than ever before; the fungus that destroyed the crop was unknown (no antidote was discovered until 1882); and Britain had suffered a bad harvest in 1846 and a financial crisis in 1847. The scale and duration of the Irish famine would have made it impossible for any British government to have coped with it, but it was calamitous for the Irish that the Russell government were anti-interventionist ideologues.
Of course, some in the British government were callous, many more were unimaginative and compassion fatigue set in early, but most of the politicians and public servants involved were trying honourably to deal with a disaster way beyond their competence.
The belief among Irish nationalists that the British can be blamed for the famine is founded to some extent on our Irish national inferiority complex. Whether complaining about the Northern Ireland of today or the Ireland of yesterday, nationalists tend to see British cock-ups as conspiracies. And there is, too, a national enjoyment of the culture of victimhood. The Irish people were "more sinned against than sinning", observed Bertie Ahern, the Fianna Fail leader who hopes shortly to become prime minister - a remark which is first cousin to republican propaganda about the Irish having been what the historian Liam Kennedy calls MOPE, the Most Oppressed People Ever.
The Prime Minister mercifully avoided setting a precedent by making an apology based on a false premise. He will shortly be asked to say "sorry" for Bloody Sunday; there are many more grievances to follow. It is time for him to take advantage of his youth and newness and say with his customary trenchancy that then was then and now is now, and that grown-up and equal neighbours should draw a line under their past and get on with making the best of their present.