Norm expresses an old fogey's scepticism about whippersnapper Owen Jones' claim that "with a bit of a shove - the whole edifice [of wealth and power] could shatter." As one of middling years, I'm in two minds about this.

I side with Norm because history suggests that social systems rarely change solely because of conscious collective action. Feudalism didn't disappear because of a peasants' revolution, and dissidents weren't the prime cause of the collapse of communism. "Whole edifices" tend to shatter not (just) when they are shoved, but when their material economic foundations weaken.

Which brings me to two reasons to side with Owen.

1. Perhaps the foundations of hierarchical capitalism are weakening. The longstanding investment dearth is a sign that capitalism can no longer see the monetizable projects it once did, and so - as Marx predicted - is now a fetter on growth rather than an engine of it. And large parts of hierarchical capitalism are faltering: retailers and the media are in decline; banks would have disappeared but for state support; and mass production has long since left the west.

2.Organizations are brittle; quite small changes can cause them to suddenly and unexpectedly collapse. This is not just true of companies but of social systems; think of the demise of communism. One reason for this is what Timur Kuran calls preference falsification. People support a system because they believe that others do so, and sometimes they wake up and realize this is not true. Thanks to this, says (pdf) Kuran, "revolutionary surprises will occur repeatedly."

Now, you might think here that, despite this, a socialist revolution is improbable.

It is, if you think a revolution is a Battleship Potemkin-type uprising of starvelings from their slumbers. But this is not the only type of revolution. The industrial revolution was perhaps the greatest transformation in human history. But it took decades, and few of those who lived through it - Marx being an exception - thought they were part of a revolution.

And perhaps we are seeing a slow-motion revolution. Credit unions and peer-to-peer lenders, owners of coffee shops competing against Starbucks, the steady rise in the numbers becoming self-employed, the growth of bloggers, tweeters and file-sharers are all taking small - not necessarily deliberate - steps away from hierarchical capitalism, just as early factory owners made small contributions to the industrial revolution.

What Erik Olin Wright calls (pdf) interstitial transformations can ultimately add up to more radical economic change than windbags on marches.