Slowly but surely, the argument over economic inequality is being settled.

Even the International Monetary Fund, an organisation that has rarely offered comfort to bleeding hearts, this week produced a study claiming to show that the widening gap between rich and poor is an obstacle to growth, not its engine. The economists behind the work dismiss "trickle down" - in so many words - as a dangerous hoax.

A consensus is developing. It applies to developed and developing worlds alike. If the real aim is growth, economic stability and general prosperity, runs the thinking, attend to your poorest citizens, to fair taxation, health, education, social mobility, and to income distribution. The IMF's analysts go so far as to suggest that inequality forever buttressed by cheap credit is a route to economic crisis.

Identifying a problem is one thing; addressing it another. The evangelists of unfettered market forces argue, first, that individual governments should not involve themselves in these issues. Wealth creation, says this rhetoric, answers every injustice. True economic liberals would add, for good measure, that there is precious little governments can achieve. If anything, their interference risks making matters worse.

Such propositions are hard to sustain. First, there is a growing body of evidence, albeit disputed, to say that countries less prone to inequality - Scotland is not among them - have been conspicuously successful, economically and socially. Secondly, it is a brave economist who will tell a population with experience of austerity that nothing can or should be done when the rich minority grow richer while the majority cope as best they can.

Where, on either side, is the evidence on inequality? David Bell and David Eiser of Stirling University, working with the Centre on Constitutional Change, begin with the recognition that the Scottish Government regards reducing inequality as one of two pillars of its economic strategy. The researchers then observe that while Labour's introduction of the minimum wage and tax credits have insulated many of the least well-off, the very poorest have suffered badly.

What can a government do? When the dust has settled on the Scotland Bill, Edinburgh will, one way or another, have more powers than before. It will have control over some taxes, some benefits, and certain spending programmes. It will also have the authority of government with which to spread the word: there is scope for change.

Even a Scottish National Party administration insistent on more fiscal powers can press on with reform of the increasingly nonsensical council tax. There is an opportunity - for the Labour opposition can hardly object - to increase the higher rate of income tax. Should the power be granted, a government committed to the Living Wage could hardly hesitate over a crucial increase in the minimum wage. Numerous other reforms to the benefits system are possible if Westminster and the electorate are willing.

Such a programme would produce predictable reactions. There would be tales, no doubt, of wealth creators in flight, of entrepreneurial spirits crushed. That would miss the point. The argument, bluntly, is that inequality harms society as a whole and benefits only a tiny minority. The gains come nowhere near to balancing the losses. By accepting inequality and poverty we slowly but surely destroy wealth. Too few can still claim that the sums add up.