When it comes to politics and the ancient Greeks, today it is generally accepted that Aristotle was good, while Plato was bad. Aristotle is the godfather of democratic theory, liberalism, equality and lots of other nice things; Plato was weird, advocating common ownership of women, children and property, under a dictatorship of "philosopher kings" (or queens).

While Plato might not be fashionable, his idea of the philosopher king has not gone away. A number of people, from Jesus to Buddha, have been compared to Plato's ideal, but more recently the term has been used to describe a shy, 73-year old Hungarian-born billionaire, George Soros – the man who broke the Bank of England.

And the label seems oddly apt. Plato said that, as a child, the philosopher king should have physical education and, only at 20, be exposed to philosophy. This mirrors Soros's youth. The philosopher king should work on his philosophical knowledge at 30 for five years – again, this is what Soros did. Then, the philosopher king should work until the age of 50, to see if they will "stand firm or flinch". In his mid-thirties, Soros turned away from philosophy and dedicated himself to business.

At 50, if he has passed this test, the philosopher king should turn to politics and "rule for the public good". In 1980, at the age of 50, Soros began to become involved in politics and, over the next twenty years, poured his fortune into an enormous range of programmes dedicated to opening up the closed societies of Central and Eastern Europe.

So far, so spooky. It is as though Soros followed Plato's programme to the letter. So is a billionaire financier, who recently said that removing President Bush from office was "the central focus of my life", really one of Plato's philosopher kings? Or do the parallels between Soros's life and Plato's programme actually only run surface deep?

The similarities go back to Soro's childhood. Plato said a child's "early education should be a sort of amusement" and have an emphasis on physical education: a fair description of George's formative years. Soros's father thought physical education was important for his children, though he did so because he thought it would increase his son's height. And Soros's early adolescence in wartime Budapest was, in his words, "the most exciting time of my life". During the war, Soros's family hid from the authorities; when the war ended, the 15-year-old George began learning the lessons of finance by trading currencies on the black market.

At the age of 20, said Plato, the next stage of the programme would see a small number of students selected to study philosophy. He believed that through such study, their previously acquired knowledge "will now be brought together", so that they will start to "see the natural relationship of them to one another and to true being." The idea of 'true being' links to Plato's biggest idea, "the theory of forms" – that everything in reality was a lesser version of an ideal model. By the age of 50, the philosopher king would know of such perfection, would know "the form of the good", and so would be able to rule in everyone's best interests.

When he was 20, Soros was in London, with little money. He had just finished his first year studying economics at the London School of Economics (LSE). As a foreigner in post-war London with few friends, Soros was not enjoying his studies and was having trouble seeing the natural relationship between himself, others and the world. But, twelve months later, his interest in philosophy had grown and, for his final year, he decided the now-legendary LSE philosopher Karl Popper would be his mentor. Though he only managed a lower second-class degree, his brief encounters with Popper had a decisive influence on the rest of his life, leading him to continue studying and writing about philosophy even as his career in finance began.

Back to Plato. The next step towards being a philosopher king begins at the age of 30. Those that "are most steadfast in their learning", and at their other duties, will be chosen for a five-year course in philosophy using the dialectic method – put simply, questions and answers. The dialectic was Plato's preferred way of learning, to the extent that many of his books are written as questions and answers between different individuals.

Soros, on the other hand, did not gain any recognition for his philosophical studies at the age of 30. And neither did he use the dialectic in his learning. Instead, he would finish work, return home, read books on philosophy and continue writing his grand essay, called "The Burden of Consciousness". At 33, Soros sent Popper a critique he had written on Sigmund Freud, and then gave the professor some more of his writings to read. But Soros got stage fright and retrieved his work, unread, a few days later. He continued to work on his philosophy for the next two years but, in the end, "The Burden of Consciousness" appears to have become too much of a load. After receiving little encouragement from Popper, he ended his philosophical project, aged 35.

On Plato's programme, at 35, the philosopher kings-in-waiting should find work, "in this way they will get their experience of life", and be tested to see whether "they are drawn in all manner of ways by temptation". At this age, Soros turned his full attention to his business activities and, in a couple of years, had become the manager of his first investment fund. It was a great success. By 1973, Soros started his own company, Soros Fund Management.

By the late 1970s, Soros appeared to have it all. He had lots of money and a close family, but he also had a therapist and a mid-life crisis. Strangely, despite his earlier attacks on Freud, his therapist was a Freudian psychoanalyst. At the heart of Soros's problems was another of Plato's rules: "they shall have no private property beyond the barest essentials".

Soros, on the other hand, had lots of money and he was having problems with the idea of all that cash in the bank. At around this time, he was quoted as saying: "I don't like making money, I'm just good at it." His biography suggests he may have initially seen making money as like playing a game, a game he was determined to win.

But, at this time, Soros was not a materialist. Though he lived very comfortably, he had no string of racehorses, no garage full of expensive cars – in fact, no car at all – and owned no large houses stuffed with Old Masters. He split from his first wife in 1978 and moved into a small flat. He then met Susan, later to become his second wife, who said of him at that time: "He moved into that tiny furnished apartment and he wanted to own nothing. He didn't want to be bothered by possessions, he wanted a totally new life."

Plato would have smiled. Just in time for the next and final stage of the programme, Soros seemed ready. But did he fulfil Plato's requirements? The old Greek said the philosopher kings should be "those who still survive and have distinguished themselves in every action of their lives, and in every branch of knowledge" – a tough test indeed. Those who had achieved this were now ready to rule, they could "raise the eye of the soul to the universal light of all things, and behold the absolute good; for that is the pattern according to which they are to order the state and the lives of individuals".

So what is this universal light? To explain this, we have to go deeper into Plato's theories. One of the things many people know about Plato is his allegory of the cave. It is a bit like The Matrix but two and half thousand years older. Imagine there are some prisoners shackled in a dark cave. They cannot move their heads and the only light in the cave comes from a fire behind them. Between themselves and the fire, puppeteers walk with cutout shapes of animals and trees, casting shadows on the wall in front of the prisoners. The prisoners have known no other reality; they believe the shapes are real, giving them names and talking about them as if they are genuine.

This, to Plato, was the human condition. But what if one of the prisoners was to escape? He would stumble out into the light – "the universal light" – and see the world for what it really was, seeing "the absolute good". The brilliant sun outside is the "form of good", the ideal of goodness.

Plato designed this 50 year training programme to enable the philosopher king to free himself from his shackles and escape into the light. But, once he had escaped, the enlightened would-be ruler should then return to the darkness of the cave and so be able to govern more wisely, being able to "see ten thousand times better than the inhabitants of the cave", who spend their time fighting about the false images they see in front of them.

So where does Soros fit into all this? First, did he distinguish himself in every part of his life? Well, he made a lot of money and to many in our society that is the main criteria of success. So he may have distinguished himself in his chosen line of work but, as a philosopher, Soros seems to have been less of success, as he himself readily admits. In his book, Soros on Soros, one chapter's title is "The Failed Philosopher".

But, despite his self-deprecation, has Soros seen the light? Has he, in his philanthropy, come down into the cave to fulfil Plato's task of the "care and providence of others"? It's a tricky one to answer but, if we look at the projects Soros has funded, we see similarities – but also differences – with the policies Plato believed the philosopher king should support.

Soros has funded many programmes based upon education. One of his most successful projects was called "Step by Step", a programme of nursery schooling for children across Central and Eastern Europe. At the same time, his foundation published fifty classic books, previously unavailable in Communist-controlled countries, in enormous numbers and distributed them to schools. Like Plato, he has set up his own Academy, the Central European University in Budapest.

He can also claim credit to saving much of Russia's scientific expertise. In 1992, as the state collapsed, Soros funded a programme where all scientists in the former Soviet Union who had published at least three articles in leading journals during the past five years would receive $500 – more than a year's pay. In all, 20 763 people received such grants, almost a fifth of all researchers in former Soviet Union national laboratories.

Plato also saw the importance of education. He believed it was a key responsibility of the philosopher king, but felt few would ever be able to escape their shackles. The rulers of the state, said Plato, should train the "best minds" to attain knowledge so they could see the universal light. But Soros believes in spreading knowledge to as many people as possible, to support democracy, an independent media and oppose dictators.

So, even if Soros does fit Plato's criteria to be a philosopher king, he does not share Plato's political ideas. This is not surprising considering that Soros's mentor, Karl Popper, loathed Plato. Seven of the ten chapters in the first volume of his book Open Society and its Enemies – the book that so inspired Soros that he named his philanthropic foundation "Open Society Institute" – were full of attacks on Plato's political ideas.

For Plato did not just believe philosopher kings would rule through reason alone; the military, in the form of "guardians", would also support them. And, unlike Popper, Plato was highly pessimistic about change, arguing "all social change is corruption or decay or degeneration". While the philosopher kings would, because of their higher knowledge, be free from corruption, Plato believed that others were irrecoverably tainted, so he said everyone over 10 years old should be expelled from the state, and the remaining children re-educated.

All this sounds distinctly dodgy – "re-education" programmes, mass expulsions, know-it-all dictators backed by the military? To modern-day readers, this does not sound like a utopia. And, to Popper, it smacked of fascism and Stalinism, as well as a long-winded justification of why the philosopher should grab control of the state himself. "The philosopher king is Plato himself, and The Republic is Plato's own claim for kingly power," wrote Popper. Since then, Soros has dedicated twenty years of his life to developing 'open societies' in Central and Eastern Europe, based upon the belief that no one has a monopoly on the truth and that a free society requires vigorous public debate.

But there is a paradox in Soros's philanthropy, one that could make him appear more like the Platonic ideal, and one his enemies have tried to use to undermine his activities. For Soros believes in democracy and accountability, but he himself has power only through the dictatorship of money. His wealth has bought him influence and, best of all, few responsibilities to anyone but himself. A long-time colleague and friend has said Soros has "more influence in the world than anyone who has never held high elective or appointive office".

This combination of immense power and lack of accountability, not to mention his career in financial speculation, has made Soros a controversial figure across the world. Despite his support for huge charitable programmes, often larger than the total amount of western governments' aid budgets, his support for civil society projects has led him into conflict with authoritarian leaders across Central and Eastern Europe. After the recent 'rose revolution' in Georgia, many in Russia and elsewhere in the region concluded that Soros engineered the coup on behalf of the American government. Ironic, since he has given groups like MoveOn.org millions of dollars to support their efforts to remove President Bush from office.

Maybe such controversies, or the difficulty of measuring his programmes' success, are the reason Soros announced last year that he would wind down his philanthropic activities. He still intends to give away all of his fortune by the time he dies, but, as he grows older, he seems more willing to accept that his charities will go on after his death, something he didn't agree with previously.

Soros is a modern-day enigma. A man who made billions from global finance, even while he wrote books attacking it; a man of great influence, but whose public power derives from his private wealth. He may not have been a successful philosopher, but he has been the most significant philanthropist since Andrew Carnegie a century ago.

Plato believed the ideal ruler would be the one who had the greatest knowledge. But Soros came to power through the size of his bank balance. However, unlike Plato's fantasyland, in this reality political power is not automatically given to those that are most enlightened.

Soros once said: "I'm a kind of nut who wants to have an impact". And billionaires with political ideals and a philosophical streak can have a lot of impact, both for good and bad. So, compared with the philosopher kings we might have suffered, we have been pretty lucky with the Hungarian we got.