Caligula, Nero, Commodus, the mad, bad Roman emperors, arouse in us pity for the people who could not find a better system of government - and, at a certain level, incredulity and incomprehension.
The same, when we read about, say, 19th century slavery in America, in which black people were bred on special farms and often worked to death over a short span of murderous exploitation in six or seven years.
Or that until not so long ago women lacked most civil rights; that women got the vote in most of Europe only after the Second World War; or that, forty years and less ago, the US democracy operated a system of apartheid which repressed and segregated black people. When we read about such things, they are, at a certain level, hard for us to take in or comprehend.
Even when we know the how and why of them, those things still arouse in us an incredulous "how could people have allowed that?"
Citizens in a better future will read that in bourgeois-democratic Britain at the beginning of the 21st century we tolerated a system in which the very rich owned the newspapers, radio and TV stations. The media controlled the flow of information and often shaped the "public opinion" of the "democracy" which then expressed itself in elections and social attitudes.
They will find that as hard to comprehend as we do the things I listed above.
If you think about it, the current perfectly legal campaign of murderous incitement by the Sun and the Express against immigrants is astonishing! It cannot but be incitement against the identifiable immigrants already here. Yet we take it as an unquestionable right of Richard Desmond (the Express) and Rupert Murdoch (the Sun) to do that.
We are so used to such things that there is little public discussion about alternatives to the present system.
Tony Blair seven years ago and Tory leader Michael Howard recently went like supplicants kneeling before a medieval prince or Pope to pay homage to the American citizen Rupert Murdoch. What did they want? The support of the great secular Pope, the controller of the Sun and News of the World, and therefore a great power in shaping British public opinion.
Things other than newspapers help form opinion, of course, but people like Murdoch nonetheless have enormous power. Take the Sun.
That paper in the 1970s, driven by commercial considerations, brought about a cultural revolution in the British popular press. Smart-ass bourgeois journalists aped the manner and speech patterns of the most backward workers to express the politics of the ruling class and to sink British political life to a new level of vulgarity, chauvinism, and blinkered indifference to social concerns. They helped give birth to Thatcherism and sustained it.
Yet the Sun was in fact founded by the labour movement. Before it changed its name in 1965, it was called the Daily Herald. It could trace its origins back to before the First World War, when George Lansbury founded it as the voice of militant trade unionism. And a fine paper it was then too.
When it became the Daily Herald, the TUC owned 50% of the shares. Those were eventually sold to a private publisher, Odhams, who however maintained it as a leftish labour movement paper. Initially, that is what the Sun was.
Until a rich man, Rupert Murdoch, took it over... Money ruled and rules.
The effect on public life of Conrad Black (Lord Black), portrayed by Jeff Randall in The Rise and Fall of Citizen Black, BBC 2, was benign compared to that of Rupert Murdoch or of the brigand Robert Maxwell, who "captured" the Daily Mirror. But the story of this Canadian bandit is woven from the same material.
It too shows up the lunacy of commercial, bourgeois, control of the mass media, and the owners' use of the media for their own commercial and political ends.
Like Murdoch, Black was born rich, and used his wealth to make himself richer. He bought Canadian provincial newspapers and made them highly profitable. How? He sacked half or more of the workforce, and squeezed more out of the surviving workers.
Increased exploitation was at the root of Black's progressive enrichment. Eventually his company, Hollinger, controlled 500 Canadian local papers.
As a friend of Black's, the creepy sycophant and historian Andrew Roberts, told the camera, Black thus became "a power in the land", someone around whom Roberts and his type of whoring intellectual could cluster like bees round the queen.
In 1985 Black bought the Daily Telegraph and the other papers associated with it. He was elevated to the House of Lords, and became a major social lion in London and New York.
So did his wife Barbara Amiel, a stone-age political rightist who claims to have been once involved in the Communist Party and is given to Imelda Marcos levels of conspicuous consumption.
Black slashed the Telegraph workforce to raise profitability by increasing the exploitation of those left. He joined in a price war with Murdoch's Times, slashing the price of the Telegraph to 30p.
But, knowing that the drop in dividends would push down share prices, he sold shares at the high price they fetched before he cut prices, making an estimated £73 million on the deal.
Black, who had always taken as his model Napoleon Bonaparte, the French parvenu who made himself Emperor of the French, soon succumbed to the occupational disease of press barons who begin to think themselves all-powerful - megalomania.
His company, Hollinger, had many other shareholders whose investments entitled them to share in what Black squeezed out of his workers. But Black controlled two thirds of the vote-carrying shares, and treated the "public
company" as private property. He took tens of millions of dollars from the company.
On top of robbing his workers - which is entirely legal, indeed the basic cell of capitalist society - Black robbed the other shareholders. That is illegal. Lord Black was not entitled to loot the shareholders.
Eventually their lawyers and their law courts caught up with him, charging him with misappropriating the shareholders' assets. He has been disgraced, forced to sell off the Telegraph group of papers, and thwarted in his bid to do so in the way most profitable to himself. He may well faced a criminal prosecution.
One magalomaniac commercial king is unhorsed - but others will take his place.
He tried to sell the Telegraph chain to two millionaires, the Barclay twins, described in the press as "reclusive".
Media mogulship is not an occupation for modest, retiring gents. A drone bee fed on royal jelly becomes a queen bee; and the capitalist feeding on the power of the mass media tends to become a "Napoleon" of his world - a megalomaniac Maxwell or Black, who plainly thought he could do anything and get away with it.
I've been trying to think of an analogy to what "we" allow such people to do. The water supply is already privately owned - and that, if you think about it, is in itself pretty lunatic.
But suppose the rights of the private owners of the water industry included the right to put anything they liked into the water they supply, including toxins and poisons. That is a rough equivalent to what "we" allow the private owners of the mass media to do to their readers and to democracy.
For the idea that there can be a viable democracy while rich capitalist cutthroats control the mass media is preposterous. It is not only that a Murdoch can dictate to a British prime minister and prime minister in waiting. He can do that only because of the power he has over the minds of those who read his commerce-driven poisonous mass media.
Someone coming from a democratic and socialist future would, I repeat, find such a situation simply incredible.