The crowd murmuring on the Town Hall steps was mostly a young crowd. They had come to see the oldest rock star in the world. Not that Jacques Derrida is really a rock star. He doesn't sing or play guitar. But his reception in Australia certainly had elements of rock and roll circus.

The first support act for Derrida's one night only Sydney performance was Gavin Brown, Vice Chancellor of the University of Sydney. Gesturing to the "controversial" nature of the main act, he pointed out that as a pure mathematician he was only too well aware of the arbitrary nature of the sign, and that his was why he enjoyed both the poetry of Mallarme and cross word puzzles.

The second warm up act was Dr. Alan Cholodenko, who gave a brilliant display of lecturing as a public performance art. The tripping rhythm of his speech, the allusions and asides that strike the mind just a little after they strike the ear -- Cholodenko at his best.

And at last -- the man himself. Jacques Derrida in conversation with Professor Terry Smith in this cavernous hall. The program was divided into the three parts. The first was a series of intricate questions about seeing, touching, writing and reasoning.

I won't try to paraphrase all of Derrida's answers -- those who are really interested can wait for the text to be published. As Derrida acknowledged for the crowd, he was being called upon to perform, to "do philosophy," live and in a foreign language. He might have said what the great soul singer James Brown always says: "watch me work."

Derrida had clearly prepared his answers to the first set of questions in advance. We might as well have just waited to read them when, inevitably, they are published. But there is some mystery at work to do with the authenticity of seeing these answers performed, spoken by the voice in our presence. The spoken word seems closer to the true word -- even if the spoken word turns out to be based on a script prepared in advance.

If we look at ourselves in the mirror, do we see ourselves seeing, or do we see what we look like? It was just one of the things that came up, and not a bad example of the philosopher at work. I don't know what the audience really expected, but in the first part of the show, the philosopher at work is what they got. Asking questions about what appears obvious. Perhaps what is obvious is just the shadow cast by some other light.

The second part concerned Derrida's writing, not about writing, but about drawing. Terry Smith showed a series of drawing by Antonin Artaud and Derrida, who knows Artaud's work very well, commented on them, this time without notes.

The person next to me thought the drawings very funny and snorted and chortled while passing notes to a friend. I couldn't help thinking about the provincialism of Australian culture, its unease with the extremes of western thought and art, its preference for the middle brow.

And I couldn't help thinking about the importance of the work of the Power Institute, who sponsored this gig. Dr. Power left his bequest for the purposes of bringing the latest thinking about art to Australia.

But there's a sense in which Australian art and letters prefer to remain unconnected to the stronger currents at work in the world -- which may be why the world so often finds current Australian art and writing just a bit insipid.

For the finale Derrida's remarked on the media. As Smith observed, it was at Derrida's Melbourne press conference that he said that the political problem of today was the media itself. When Derrida confirmed that this was indeed what he had said, the crowd applauded. But Derrida hastened to add that it was not a topic on which he had anything original to say.

He stressed the importance of not trying to be totally against the media, as if there were an "outside" to it. But at the same time, he wanted to look for people within the media with whom to think about its ethical responsibility. The media, he said, are not just citizens of a country, not just citizens of the world, but something more than citizens.

What can this mean? He didn't elaborate. But it is an interesting place to start thinking. The media are a power in the world. Derrida stressed the importance of a critical relation to it. By this he meant the ability to question the obviousness of its signs. What appears to be "live" and direct is always also constructed in advance -- whether it is CNN news or the live webcast of Jacques Derrida at Sydney Town Hall. In short, Derrida advocated the importance of media studies.

But the media are also a force for democracy, only never purely so. The ambiguous, double role of the media, as shadow and light, might seem a long way removed from the philosopher's parable about Plato's cave, which was mentioned early on in the night. But in a way, it's the same problem.

In Plato's cave, people mistake the shadows cast on the wall for the world. The philosopher is the one who can escape from the cave and see the world in the light of day, and see the objects moving in it that cast the shadows into the cave.

But as Derrida said, one can see in the light but you cannot see the light itself. There's always the problem of knowing how it is that we come to know. Philosophers, like journalists, want to see things "as they are," not merely their shadows. But this desire keeps bumping up against its limit. We never quite see the light, we never quite hear the word, "from the horse's mouth." Even when we hear the word, the word of Derrida, it is scripted in advance.

One thing Derrida did demonstrate for anyone with eyes to see or ears to hear, is that these difficulties are things to be grappled with. It's a question of asking questions, exploring the difficulties of trying to see clearly, think clearly, and exploring them from "within." There's no magic way to escape from the cave, from the problem of working through the means at our disposal for representing to ourselves the problem of representation itself.

Derrida often gets bad reviews in the press -- mostly from people who haven't read his books or seen the show. There was a particularly obtuse piece of nonsense in the Sydney Morning Herald from one John Sharpe, for example.

Part of the problem is I think that journalists intuitively know that Derrida is on about the same sorts of problems that are fundamental to journalism. The problem of how we know what we know.

What is good reporting? It's a fundamentally philosophical question, a very ancient question. And it's a question readers are asking themselves all the time, even if journalists would prefer not to listen.

What would it mean to say that the media have to be not only a citizen of the world, but something more than a citizen? One other thing the media might need to be is the philosopher. Its not enough to make pictures and words. One also has to ask questions about pictures and words. The questions people outside the media ask about their relation to it all the time. Questions philosophers have thought about for two and a half thousand years.

Artaud's violent, sexual, clumsy drawing might seem far removed from the daily TV news. But perhaps it is already a commentary on what the news has become -- our theatre of cruelty. Derrida's complex, subtle thought might seem far removed from Neighbours on TV -- but then word "deconstruct" was actually uttered on that show this week. The problem of signs and their significance. The problem of knowledge and how we know it, are not esoteric or academic -- they are everyday life.