Theresa May's speech this morning was trailed as a defence of free market capitalism. If that's what it was, it failed because she failed to answer the big questions.

May said:

A free market economy, operating under the right rules and regulations, is the greatest agent of collective human progress ever created.

This is true. The excellent economics course devised by Wendy Carlin and Sam Bowles begins from this very fact. But it is a fact upon which Marxists agree. Marx and Engels wrote that

[Capitalism] has accomplished wonders far surpassing Egyptian pyramids, Roman aqueducts, and Gothic cathedrals...The bourgeoisie, during its rule of scarce one hundred years, has created more massive and more colossal productive forces than have all preceding generations together.

The question is: can this continue? Marx - following classical economists' forecasts of a stationary state - predicted that it wouldn't, and that capitalist property relations would turn into "fetters" which constrained growth. The fact that we've had a decade of falling real wages and stagnant productivity is consistent with the possibility that Marx was right. Maybe a falling rate of profit, fear of competition, capitalist hierarchy and state-backed monopolies are constraining growth. If so, we might need something close to the overthrow of capitalism to restore growth.

Do we? May doesn't even consider the question.

Nor does she ask its correlate: why exactly have wages and productivity flatlined for so long? If it's not because of structural capitalist stagnation nor presumably because of fiscal austerity then why? And if there are policy changes that can remedy these, why have they not been implemented since 2010? Yes, Ms May speaks of progress in financial regulation. But does she seriously think this is sufficient to end financial crises - that we've finally achieved an end of history in which crises are abolished?

Yet another question is: do we really have a free market economy? In many sectors, the answer is: no. Banks and utilities are far more like rent-seeking state-aided oligopolies than the textbook perfectly competitive markets. There's a reason why Labour wants to renationalize railways and utilities and not your local greengrocer: it's because some are monopolistic and others aren't. Labour's nationalization plans are not an attack upon markets - at least not on well-functioning ones.

Which raises a further question: what is the relationship between capitalism and markets? Yes, historically the two have been correlated. But this is not a logical necessity. Capitalism is about who owns productive assets; markets are about how goods are allocated. Capitalism can actually undermine free markets, as bosses seek monopoly profits and as crises and stagnation undermine public support for markets.

It is theoretically possible to have markets without capitalism; see, for example, Gary Chartier and Charles Johnson's book, Markets Not Capitalism (pdf). In fact, in my not wholly idiosyncratic notion of socialism, markets would be healthier than they are under today's capitalism.

Which leads to another question: are the Tories really able to defend free markets any more? The problem is that, as Phil says, they are the allies of the most "socially useless section of capital": rentiers, low-wage bosses, tax-dodgers and a few financiers. This is not the group we should look to for an advancement of healthy markets.

I like to think that there should be a case for free markets. This requires that they operate in frameworks that constrain rent-seeking and exploitation. It's not at all clear that the Tories can make such a case.

* To his credit, Tim Worstall has always been clear about this.