In order to drive the government, it helps to be able to see out the windscreen. If you turn off your headlights while driving at night, no-one will be surprised when you crash.

Unfortunately, the government led by Tony Abbott has never understood this. When it comes to things like science, evidence and statistics, the government appears increasingly deluded.

By “deluded” I mean the psychological definition of a “a rigid system of beliefs with which a person is preoccupied and to which the person firmly holds, despite the logical absurdity of the beliefs and a lack of supporting evidence.”

Nothing could better describe the mindset of the Abbott government, which has consistently made policy for a reality it wishes exists, rather than the everyday reality that actually does exist.

If there is a fundamental signature to this government, it is its determination to see Australia and the world through a conservative prism. Where reality doesn’t fit the Abbott government’s predilections, that reality is ignored.

One aspect of this tendency is a puzzling irrationalism. No government in modern Australian history has been more hostile to evidence, science and reason than Tony Abbott’s.

The rot set in almost from day one. Tony Abbott’s cabinet didn’t even include a minister for science.

After just two weeks in office, the government sacked Climate Commissioner Tim Flannery. As the head of the Climate Commission, Flannery’s role was to try and communicate climate science to the general community. He was doing a good job of presenting the scientific reality. That made him a figure of hatred for the climate warriors of the right.

Flannery was fired, and the Commission abolished. It was the opening shot in a war on science.

Once in office, the Abbott government slashed funding to climate and environment programs. It has tried and failed to kill off the Australian Renewable Energy Agency (ARENA). It has tried and failed twice to abolish the Clean Energy Finance Corporation, an energy industry bank set up by Julia Gillard. Bizarrely, the CEFC is actually making the Commonwealth money.

The Coalition also took aim at scientific research. In the last week of the 2013 election campaign, it pledged to slash $100 million from the nation’s premier research body, the Australian Research Council. Just to make sure everyone knew the score, Joe Hockey backgrounded some friendly News Corporation journalists with a number of supposedly trivial research projects that he said didn’t deserve funding. One unlucky philosopher at the University of Sydney found himself ridiculed for his work on Hegel.

In Hockey’s first budget, more cuts to science and research ensued. $111 million was cut from the CSIRO – nearly a thousand jobs have since disappeared. There were also cuts to the Australian Institute of Marine Science, the Australian Nuclear Science and Technology Organisation, the Cooperative Research Centres, to federal R&D funding, to research PhD student funding, and to virtually every federal renewable energy program.

It’s not just science, mind you. The Abbott government has taken a dislike to evidence of almost any kind. It's trying to amalgamate the Australian Institute for Health and Welfare, which collects vital health statistics like hospital waiting times. It wants to abolish the Australian National Preventive Health Agency, which coordinates policy and research for preventative health.

This wilful delusion is a key reason the Abbott government finds itself so unpopular. If it had paid more attention to the evidence on higher education or health reforms, it might have sidestepped the minefields it has blundered into.

For instance, if the government had looked at the evidence in health policy, it might have saved itself from its disastrous idea to introduce a GP co-payment. Public health actually saves the health budget money in the long term.

But looking at the evidence is not something this government seems capable of. So perhaps we shouldn’t be surprised that the Abbott government is considering cutting funding to Australia’s census – or even axing it altogether.

Before we get too worked up at the government, it appears as though the ABS has itself proposed the move to abandon the five-yearly survey.

But the reason for that move is almost certainly declining funding. The census costs more than $400 million to conduct. But the ABS has been starved of funds in recent budgets, including under the previous Labor administration.

Last year’s budget cut $68 million in funding for the Australian Bureau of Statistics. The ABS had to cut so many staff, its unemployment numbers became unreliable.

Why should we keep a five-yearly census? It’s simple: we need it.

The census is Australia’s premier public policy measurement. Demography is destiny, as the old saying goes. You can’t get a more fundamental social indicator than who lives where. Without a proper measure of the population, governments at all levels can’t plan for the next hospital, school, road or police station.

The census counts, because only the census counts everyone. Our public services run on high-quality statistics. The census is the foundation stone of the entire statistical edifice.

Only the census gives us the highest-quality data at the lowest level in the most detail. Many of the other statistics we rely are based on the census for their very statistical validity. Even the opinion polls that politicians pay so much attention to are based, ultimately, on the census. It is only with reference to census data that pollsters can build statistically significant and unbiased samples that reasonably reflect demographic reality.

Cutting back on census quality runs the risk of ruining decades worth of data. That’s because many of the measures the ABS keeps are based on asking the same questions, in the same way, every five years. If we change the method, the data no longer becomes comparable. All of a sudden, future editions of long-running series like the Survey of Income and Housing might be compromised.

We know this can happen, because Canada has already tried it. When the Canadian government of Stephen Harper – another science-hating climate denier who has much in common with Tony Abbott – cut back on census funding, the results were dismal. The quality of the new surveys were so poor that they became almost useless at a local and regional level.

The party that should be most opposed to this idea is the Nationals. Regional and rural communities will suffer most from a damaged census, because the data for these smaller communities will no longer exist.

The government can afford to fund a proper census. It’s proposing to pay hundreds of millions to internet service providers to help with the cost of its absurd data retention bill.

But don’t expect the government to listen. As we’ve learned in the recent leadership turmoil, Tony Abbott finds any criticism difficult to handle. Like the other evidence pointing to his impending downfall, he’d rather shoot the messenger that listen to the message.