Instead of lamenting the silliness of a lot of social online media, we should be thrilled by the spontaneous collective campaigns and social activism also emerging.
The potential civic value of all this hitherto untapped energy is nothing less, Shirky concludes, than revolutionary.
Unfortunately, I am precisely the sort of cynic Shirky's new book scorns - a techno-luddite bewildered by the exhibitionism of online social networking (why does anyone feel the need to tweet that they've just had a bath, and might get a kebab later?), troubled by its juvenile vacuity (who joins a Facebook group dedicated to liking toast?), and baffled by the amount of time devoted to posting photos of cats that look amusingly like Hitler.
I do, however, recognise that what I like to think of as my opinions are really emotional prejudices.
But equally, Shirky's prediction for Murdoch's paywall sounds suspiciously like an emotional objection, rather than a financial calculation.
How, then, can he be certain his entire analysis of the internet isn't just as subjective as my kneejerk cynicism?
"I'd say first of all that the notion that any expression of the world can be a value-neutral description of what life is really like is a fantasy, right?" he agrees readily.
"We're all postmodern enough to recognise that any writer on any subject is operating within those constraints. And I have the amiably simple-minded view of this stuff you would expect from an American, which is that I think freedom is good, full stop.
"So therefore I think I'm probably constitutionally incapable of seeing a massive spread in those freedoms as being anything other than salutary for society.
"But ultimately, over the long haul I'm vetted on accuracy, not on enthusiasm. So if I'm wrong about paywall, I've got no place to hide. I will have been flamingly, publicly wrong for 15 years. There will be no way I can weasel out of it."
He laughs, looking sublimely untroubled by this possibility.
"The final thing I'd say about optimism is this. If we took the loopiest, most moonbeam-addled Californian utopian internet bullshit, and held it up against the most cynical, realpolitik-inflected scepticism, the Californian bullshit would still be a better predictor of the future.
"Which is to say that, if in 1994 you'd wanted to understand what our lives would be like right now, you'd still be better off reading a single copy of Wired magazine published in that year than all of the sceptical literature published ever since."
The one point of agreement between internet utopians and sceptics has been their techno-deterministic assumption that the web has fundamentally changed human behaviour. Both sides, Shirky says, are wrong.
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