The desire to have your cake and eat it makes a person sound greedy, but it is more than anything a failure of intellect.

From the football manager who wants more consistent refereeing but objects when this leads to a penalty award against his team, to a president who disputes the basis of his predecessor’s employment figures but boasts of his own results using the same measures, it is hard to trust those who try to stake out a position and claim all the benefits but none of the costs.

I found myself thinking about this listening to some of the criticism levelled at finance secretary Derek Mackay’s budget this week. It was cast as a “tax triple whammy” by the Conservatives and sections of the press.

A relatively modest council tax rise, powers to impose tourist taxes and workplace car parking charges, added to the refusal to pass on tax cuts delivered in England amount to a ‘savage cash grab’, according to one report.

Here’s the thing. You can’t have socially progressive policies and a tax-cutting agenda. Some would contend you can.

Politicians, taxi drivers, bar-room philosophers – listen to them for long enough and you’ll eventually hear the hoary lie: “I’m socially liberal, but fiscally conservative”. And at that point it’s time to leave the bar, the car, or turn off Twitter.

As society becomes more progressive and permissive and voters become more concerned about issues like homelessness, more open-minded about drug reform, those on the right have had to move to appear more caring. But it is a nonsense, founded on a lie.

One of those lies is implied. That is the suggestion that liberal values are somehow profligate or wasteful. So cuts can be made with a clean conscience – it’s just belt tightening, after all.

These claims don’t add up. That’s why brutal austerity cuts are often paired with the demand for imaginary ‘efficiencies’, why councils are asked to make savings, charities providing public services are told to make do with less, and care homes are given smaller sums per head for their elderly residents.

As if that doesn’t mean larger case loads for social workers, putting every child protection case on their list at greater risk. As if that doesn’t mean fewer resources for a hospice to help people, or their relatives, at the end of life. As if it doesn’t mean Aunt Maureen in Cherry Acres is less likely to get out for a walk because there’s nobody free to keep an eye on her.

The truth is, fiscal conservatism perpetuates inequality. Poverty is entrenched by a philosophy which says, in essence: I’m really concerned about people who don’t have enough to get by, and by the problems faced by those left on the margins by society. I just don’t want to have to do anything about it, or pay anything to fix it.

That’s why the liberalism of those who espouse such views is often passive. In favour of gay marriage. Happy with freedom of choice when it comes to abortion. Pretty concerned about plastic pollution. Just so long as it doesn’t involve doing very much, or any significant government spending.

Making a real difference to the rights of low paid workers, by restoring legal aid for discrimination cases? Investing in public transport? Requiring companies to put genuine measures in placed to support disabled people in the workplace? Putting real funding behind efforts to limit carbon emissions? Well, that’s a different matter.

The perspective is a superficially attractive one. Who could be against being frugal? Especially if it’s moderated with a dose of compassion? But the reality of such thinking is that Glasgow City Council is currently considering closing Whitehill baths, home to one of only two disabled swimming clubs in the city. Edinburgh’s Integration Joint Board is about to close Pilton Community Health Project, a remarkable multi-faceted resource which has provided a range of mental health and other care and support services to some of the poorest areas of that city for more than three decades.

The reality is a benefit cap for people with more than two children so cruel that it will require some women to testify that a child was the result of a ‘non-consensual conception’ if they are not to be denied tax credits.

There is a huge self-delusion involved in the idea that perpetually cutting back on public spending is compatible with creating a fairer, kinder or more tolerant society.

So it is no surprise, I suppose, that it often comes paired with another pernicious delusion: that “the market” will somehow intervene. Fiscal conservatives have a touching faith in the powers of this magical entity.

But corporations can’t be trusted to do the right thing. Tobacco company Philip Morris is currently positioning itself as “committed to creating a smoke-free future”, in Britain, at least, where it is illegal to advertise cigarettes. Of course in other parts of the world, where it is legal, the company continues to push Marlboro for all it is worth.

And the rush of companies removing plastic straws from their products may be sincere in their response to genuine public concerns, but relying on businesses answerable primarily to their shareholders to do anything more meaningful about plastic packaging or rein in the insane market for bottled water, or discouraging overconsumption is frankly naive.

Fiscal conservatism paired with social liberalism means pushing the idea that getting into work is a straightforward answer to poverty and injustice, while turning a blind eye to the fact that starving people off benefits for the most part merely, forces them into low paid, insecure employment, perpetuating inequality.

The real answer is progressive taxation, funding efforts to tackle the attainment gap in education, address inequalities in health care, re-establish a social security safety net which treats people fairly, decently and with respect.

Two thirds of the Scottish Parliament were elected on this sort of platform, and the Scottish Government has passed a budget, with the support of the Greens, which hopes to deliver on it. So talk of ‘tax bombshells’ is misguided and regressive, especially when paired with claims to be socially liberal.