This piece has just gone up at the Guardian's Comment is free...

We will miss Rowan Williams when he is gone. Not because public life will be the poorer without that beard, those eyebrows: Boris Johnson's blond mop can fill the gap. Not because conservatives and liberals alike will lose a ready scapegoat: there will be others upon whom to load our discontent. But because he is, to my mind, the leading public intellectual of his generation.

I know that reading him can be like watching a jellyfish disintegrate in a jacuzzi, as one notable commentator memorably put it. My own version of that experience came after attending his lectures at university. During the series, I bumped into a friend on the high street and exclaimed: "why weren't you there?" After an excuse, they asked me what had been said. I stumbled and tried to explain before realising that the great man's words can seem like bright soap bubbles, bursting as they rise in the air. But of this I was sure: I wanted my friend to be there because it was obvious that something important was being aired, something unexpected would be said. Those words came from a place of vitality. Here is someone whom Aristotle would have called megalopsyche or "great souled". You want to sit alongside such humans on the rare occasions they come your way, which is presumably why even his biggest ideological opponents have done so.

It is always worth reading the archbishop for yourself, not how he is redacted in the press. Hoping you might agree, here is what I hear him saying in the new introduction to his collected lectures, Faith in the Public Square, crucial elements lost in the reports of last weekend's media.

He does criticise the way the economy is run when focused on growth for growth's sake. He does have a pop at his predecessor, Lord Carey, who has complained that Christians are being persecuted in this country. But what is missed in the headlines are the deeper, penetrating points. "We have been hearing a lot about the dangers of 'aggressive secularism'," he writes, but that noise obscures the fact that the notion of secularism does not describe where our society is at. (Keeping up the noise presumably suits the "aggressors".)

Most people do not live in a disenchanted world. Public rituals persist. I write as the Red Arrows fly overhead, celebrating the Olympics. Why do acrobatic jets suit the moment? Is it the roar? The colour? It is hard to say, which is partly why the ritual works. So if we are to progress crucial questions about how society can be organised around a diversity of beliefs, Williams continues, hadn't we better be clearer about where we are actually at?

The way he frames his interventions is striking too. To attempt to be a public commentator of any weight, he stresses, is to be doomed to failure. Some will accuse you of straying into their territory. Others will accuse you of platitudinous dumbing down. Others again will make the case for inscrutability. Williams knows he will fail. He signed up to that when he signed up to Christianity because Christianity recognises that failure is what human beings do. And yet, the recognition is not humiliating but liberating "because it delivers us from aspiring to mythic goals of absolute human control over human destiny".

He practises the risk he preaches. In the interview he gave at the weekend, he floated the idea of a president of the Anglican communion to relieve the next archbishop of his global duties. He is undoubtedly right that the job is impossible and will become more undoable. That solution, though, would surely sink the church into further division and squabbles. Can you imagine the power struggle that would ensue in the selection of such a figurehead?

In the book, Williams continues: "The best thing to hope for is that at least some of the inevitable mistakes may be interesting enough (or simply big enough) for someone else to work out better responses." Which professional politician would and could express such mitigated optimism? Actually, I suspect Boris conveys a not dissimilar stance and that is part of his appeal. Maybe the hair does matter.