Some of the Scottish left have argued that independence will usher in an era of progressive politics in Scotland.

But you could sketch a case for an independent Scotland moving in precisely the opposite direction.

The SNP's capacity to fund increased public spending, as it promises to do, depends on a commitment to raise the necessary funding.

The question is how will it manage this if, as promised, it reduces corporate taxation and does not raise income tax.

This is because the party believes that growth will follow independence through increased levels of inward investment premised on the lower corporation tax and continued growth in existing staples of the Scottish economy like oil and gas. Both of these assumptions are challengeable.

In the words of the STUC, "There is no credible evidence demonstrating a link ... between low [corporation tax] rates and high levels of capital investment or R&D spending."

And second the price of oil is volatile.

Meanwhile the loss of income to the state, necessary for social spending, may be considerable.

In these conditions arguments for the need to reduce public spending, as the Institute for Fiscal Studies argued last week, might well prevail.

The Scottish Social Attitudes Survey in January showed that 52 per cent of Scottish voters think that benefits for the unemployed are too high and discourage people from finding a job, despite evidence from an Edinburgh University study in November 2013 which showed that decent levels of benefits for the unemployed do not lead to a lack of motivation to find work.

But what value has evidence in the face of prejudice?

And the political forces behind the SNP, including Brian Souter of Stagecoach, Jim McColl of Clyde Blowers and former Royal Bank of Scotland chairman Sir George Mathewson, will be keen to promote the virtues of public penury.

But what about the arguments that the power of capital somehow depends on, and is sustained, by the constitutional relationship between Scotland and the rest of Britain?

What independence would mean is that Scotland would be subject to the power of corporate capital vested in the City of London without any say in how that power is exercised because Scots would not have a vote for the Westminster politicians who have political jurisdiction over those institutions.

Undeterred, the Jimmy Reid Foundation has come up with a detailed strategy for pushing an independent Scotland towards the left but hardly one, I would argue, that grips the socialist imagination. It is called the Common Weal.

On ownership of the economy it says nothing about the top 20 companies and instead emphasises the role of small and medium-sized enterprises in transforming the Scottish economy.

As John Foster points out in the Red Paper, there are upwards of 80,000 such firms in Scotland with a range of employees of between two and 250 and they are mainly in services. Few export directly. Many are suppliers to single, larger firms like Ineos Grangemouth or BAE systems and hence vulnerable to changes at that level, as we saw over the Ineos crisis. These are hardly the engine of economic transformation.

Furthermore in so far as the Common Weal promotes public ownership, it is not primarily in terms of economic power - giving democratic control of the economy to those who produce the wealth - and there is no serious discussion of how, for example, key sectors of the economy like transport could be brought back into public ownership. Instead the Common Weal focuses on state interventions necessary because of market failure.

From a left-wing perspective the section on democracy and governance is positively alarming.

It adopts an unashamedly partnership model for trade unions. It argues for "strong trade unions working collaboratively with employers not only on employee remuneration issues but also on strategic management issues."

This is the model which some Irish trade unionists would argue has been devastating in terms of their capacity to resist austerity. It sits very well, by contrast, with the corporatist thinking of the big business backers of the SNP.

The Red Paper Collective is only too conscious that exposing the limitations of arguments for a Yes vote from the left might be taken as counsel for despair.

There is considerable evidence that the people of Scotland would like additional powers for the Scottish Parliament.

To achieve a progressive Scotland we obviously need the kind of powers outlined in the Red Paper.

Achieving a progressive Britain would be greatly helped by the emergence of regional assemblies in England along with those already in existence in Northern Ireland and Wales so that a radical federalism might emerge.

Working together regional parliaments could act as a brake on the worst excesses of the Westminster Parliament, if that was necessary, and promote radical alternatives within their powers. That is, after all, what both the Welsh Assembly and Scottish Parliament have done already when acting at their best.

This is the only serious strategy for sustaining a united working class and winning jobs, peace and security in Scotland and Britain and through that establishing an irreversible shift of wealth and power in favour of the working class.

Vince Mills is a member of the Red Paper Collective (www.redpaper.net) and a contributor to Class, Nation and Socialism: Red Paper on Scotland 2014