I thought Thatcher a blight but Mandela was a blessing

It's not reality, not in the deepest sense. It is probably no more than shorthand for the idea that sometimes a single event can catch the attention of an unusually large number of people. The event itself might turn out not to have mattered much, or it might be remembered long afterwards for consequences profound, troubling or cheering. You never know for sure.

Reactions of the death of Diana, Princess of Wales, now seem less important than utterly peculiar. The hysteria, especially in London, was very real; the historical significance of a single awful accident was slight. In contrast, the shockwaves from 9/11 are still being felt in every corner of the planet. Whole societies have been altered, perhaps permanently, not for the better, by one atrocity.

Journalists, and this is not news, have no prophetic gifts. Sometimes, though, you can see "historic" approaching and you can prepare. When well-known people grow old, obituaries and TV packages are made ready. Questions and answers are anticipated, with luck. Images and statements are selected. The jury of peers is rounded up, often long in advance, to offer praise or blame.

Neither the death of Margaret Thatcher nor the passing of Nelson Mandela came as a surprise. Both of those tenacious people had me sketching out my efforts at paragraphs and pages long before their ends came. But, even with forewarning, the simple fact of death made every prepared word seem provisional. Some answers were still hard to come by.

Something needed to be said, for all that. Wasn't my writing calendar for 2013 shaped by the disappearance of these two individuals? Didn't a big enough part of my working life rest on what they were supposed to have represented? Thatcher and Mandela: contrast, compare and choose. Easy enough, in one sense, but no aid if you are puzzled by mysterious questions.

I didn't care for Margaret Hilda Thatcher as a human being. In all the years of writing down opinions I found not a word that would have counted in her favour. When her government fell upon mining communities in the middle of the 1980s it seemed to me, and still seems to me, that something vile and ruthless was loose in the world.

Later, I spent an entire year, so it seemed, making fruitless phone calls to the London paper I worked for repeating that "this poll tax thing" was a monstrosity, a story about to happen, and one of those famous defining moments in the life of a government. My colleagues caught up with the argument in due course. In Scotland, it appeared to me that some pretty basic notions of democracy were under threat.

But I also knew that some, perhaps many, adored Margaret Thatcher. They called her an emancipator. They admired what they saw as her courage. They found her resolute, heroic, clear-eyed, and devoted unflinchingly to a belief in a better society. Someone was wrong. What's more, one group of people understood the world in a way that was incomprehensible to others. Crudely, two utterly opposed views of human nature were at work.

Despite all the frantic attempts to rewrite history after his passing, Margaret Thatcher had not the slightest understanding of Nelson Mandela. The "typical terrorist" remark was, if you like, typical. The notion that she spurned him publicly while working for his release behind the scenes was fanciful enough to remind you that even Tories who venerate our only woman prime minister were uneasy, let's say, over her attitude towards apartheid and her selective definitions of freedom.

Margaret Thatcher saw the world through a single prism. I still contend that her view was utterly distorted; her adherents say the opposite. That fact leaves us with a few tricky questions about the world, and therefore about politics. If I said then, as I would say now, that Nelson Mandela was a Marxist freedom fighter with a larger idea of what it means to be human than most people in the 20th century, where does that leave the adored Tory leader?

It is hard to split hairs over a question like that, though plenty have tried. It is harder still to get away with the usual party-political platitudes, to advance the claim that Mandela and Lady Thatcher both believed in "freedom", but in different yet somehow parallel ways. The circle isn't squared. The eulogies sound empty. What can't be denied is the sincerity of belief on either side of the argument.

If that's true, it means that much of what passes for political debate is a waste of time. Conversions are few; minds aren't often changed. The socialist who becomes a Thatcherite (or vice versa) doesn't bear much examination. Nelson Mandela might have compromised over economics to keep South Africa intact after he assumed office, but his embrace of Fidel Castro was sincere. Margaret Thatcher, famously, did not believe in consensus, or in compromise.

She liked to think of herself as a conviction politician. Mandela, few would deny, earned the equivalent distinction many times over. Yet on his passing his former enemies fell over themselves to praise his capacity for forgiveness and reconciliation, as though that had been his life's only purpose. It seems he understood there was only one alternative: warfare, political or actual. Oddly enough, Margaret Thatcher had the same belief. But she enjoyed the contest.

Mandela understood, acutely, that winning the combat in South Africa would not solve the country's problems. Lady Thatcher was only too delighted to call her fellow Britons the enemy within and to "take them on", whatever the damage or the cost. Yet she won no hearts and precious few minds worth winning. Instead, she reminded us that sometimes convictions cannot be reconciled.

This might be why people are prone to saying that all modern political parties are more or less the same. In that truth hides an unspoken agreement. A Thatcher and a Mandela represent two wholly opposed views of what it means to be human. That cannot be argued out or settled with a little good will among sensible folk. So the ones who regard themselves as sensible take power to themselves and ignore reality.

A good question to ask when this year's calendar is discarded might involve what is still possible in political affairs. Could we have the luck to encounter another Mandela, the misfortune to face another as mad as Thatcher? Across the world, people in suits cut deals to ensure such things no longer happen. In "the mainstream", politicians and their parties are much of a muchness. It's no accident.

It amounts to a deceit, nevertheless. I thought Margaret Thatcher a blight and Nelson Mandela a blessing. Others, beyond my comprehension, would say the opposite. But that mutual incomprehension remains humanity's incurable condition.