Those whom the gods love die young: are they trying to tell me something? Due to an inexplicable discontinuity in space-time, on Sunday I turned 50. I have petitioned the relevant authorities, but there's nothing they can do.

So I will use the occasion to try to explain the alien world from which I came. To understand how and why we are now governed as we are, you need to know something of that strange place.

I was born into the third tier of the dominant class: those without land or capital, but with salaries high enough to send their children to private schools. My preparatory school, which I attended from the age of eight, was a hard place, still Victorian in tone. We boarded, and saw our parents every few weeks. We were addressed only by our surnames and caned for misdemeanours. Discipline was rigid, pastoral care almost non-existent. But it was also strangely lost.

A few decades earlier, the role of such schools was clear: they broke boys' attachment to their families and re-attached them to the institutions – the colonial service, the government, the armed forces – through which the British ruling class projected its power. Every year they released into the world a cadre of kamikazes, young men fanatically devoted to their caste and culture.

By the time I was eight those institutions had either collapsed (in the case of colonial service), fallen into other hands (government), or were no longer a primary means by which British power was asserted (the armed forces). Such schools remained good at breaking attachments, less good at creating them.

But the old forms and the old thinking persisted. The school chaplain used to recite a prayer that began "let us now praise famous men". Most of those he named were heroes of colonial conquest or territorial wars. Some, such as Douglas Haig and Herbert Kitchener, were by then widely regarded as war criminals. Our dormitories were named after the same people. The history we were taught revolved around topics such as Gordon of Khartoum, Stanley and Livingstone and the Black Hole of Calcutta. In geography, the maps still showed much of the globe coloured red.

My second boarding school was a kinder, more liberal place. But we remained as detached from the rest of society as Carthusian monks. The world, when we were released into it, was unrecognisable. It bore no relationship to our learning or experience. The result was cognitive dissonance: a highly uncomfortable state from which human beings will do almost anything to escape. There were two principal means. One – the more painful – was to question everything you held to be true. This process took me years: in fact, it has not ended. It was, at first, highly disruptive to my peace of mind and sense of self.

The other, as US Republicans did during the Bush presidency, is to create your own reality. If the world does not fit your worldview, you either shore up your worldview with selectivity and denial, or (if you have power) you try to bend the world to fit the shape it takes in your mind. Much of the effort of conservative columnists and editors, and of certain politicians and historians, appears to be devoted to these tasks.

In the Origins of Totalitarianism, Hannah Arendt explains that the nobles of pre-revolutionary France "did not regard themselves as representative of the nation, but as a separate ruling caste which might have much more in common with a foreign people of the same society and condition than with its compatriots".

Last year the former Republican staffer Mike Lofgren wrote something very similar about the dominant classes of the US: "the rich elites of this country have far more in common with their counterparts in London, Paris, and Tokyo than with their fellow American citizens … the rich disconnect themselves from the civic life of the nation and from any concern about its well being except as a place to extract loot. Our plutocracy now lives like the British in colonial India: in the place and ruling it, but not of it."

Secession from the concerns and norms of the rest of society characterises any well established elite. Our own ruling caste, schooled separately, brought up to believe in justifying fairytales, lives in a world of its own, from which it can project power without understanding or even noticing the consequences. A removal from the life of the rest of the nation is no barrier to the desire to dominate it. In fact, it appears to be associated with a powerful sense of entitlement.

So if you have wondered how the current government can blithely engage in the wholesale transfer of wealth from the poor to the rich, how its frontbench can rock with laughter as it truncates the livelihoods of the poorest people of this country, why it commits troops to ever more pointless post-colonial wars, here, I think, is part of the answer. Many of those who govern us do not in their hearts belong here. They belong to a different culture, a different world, which knows as little of its own acts as it knows of those who suffer them.

Twitter: @georgemonbiot. A fully referenced version of this article can be found at Monbiot.com