For the last three years or so I’ve been arguing with anti-vaccination activists. In the process I’ve learnt a great deal – about science denial, the motivations of alternative belief systems and the sheer resilience of falsehood.

Since October 2012 I’ve also been actively involved in Stop the AVN (SAVN). SAVN was founded to counter the nonsense spread by the Australian Vaccination-skeptics Network. According to anti-vaxxers SAVN is a Big Pharma-funded “hate group” populated by professional trolls who stamp on their right to free speech.

I’m afraid the facts are far more prosaic. There’s no Big Pharma involvement – in fact there’s no funding at all. We’re just an informal group of passionate people from all walks of life (including several research scientists and medical professionals) who got fed up with people spreading dangerous untruths and decided to speak out.

When SAVN started in 2009, antivax activists were regularly appearing in the media for the sake of “balance”. This fostered the impression of scientific controversy where none existed. Nowadays, the media understand the harm of false balance and the antivaxxers are usually told to stay home.

There’s a greater understanding that scientists are best placed to say whether or not something is scientifically controversial. (Sadly we can’t yet say the same for the discussion around climate change.) And there’s much greater awareness of how wrong – and how harmful – antivax beliefs really are.

No Jab, No Pay

This shift in attitudes has been followed by significant legislative change. Last year NSW introduced ‘No Jab, No Play’ rules. These gave childcare centres the power to refuse to enrol non-vaccinated children. Queensland and Victoria are planning to follow suit.

In April, the Abbott government introduced ‘No Jab, No Pay‘ legislation. Conscientious objectors to vaccination could no longer access the Supplement to the Family Tax Benefit Part A payment.

The payment has been conditional on children being vaccinated since 2012, as was the payment it replaced. But until now vaccination refusers could still access the supplement by having a “conscientious objection” form signed by a GP or claiming a religious belief exemption. The new legislation removes all but medical exemptions.

The change closes loopholes that should never have been there in the first place. Claiming a vaccination supplement without vaccinating is rather like a childless person insisting on being paid the Baby Bonus despite being morally opposed to parenthood.

The new rules also make the Child Care Benefit (CCB) and Child Care Rebate (CCR) conditional on vaccinating children. That’s not a trivial impost – estimates at the time of the announcement suggested some families could lose around $15,000 over four years.

What should we make of this? A necessary response to an entrenched problem or a punitive overreaction?

Much of the academic criticism of the policy has been framed in terms of whether it will in fact improve vaccination rates. Conscientious objector numbers do now seem to be falling, although it remains to be seen whether this is due to the new policies.

Embedded in this line of criticism are three premises:

• Improvements in the overall vaccination rate will come through targeting the merely “vaccine-hesitant” population.

• Targeting the smaller group of hard core vaccine refusers, accounting for around 2% of families, would be counterproductive.

• The hard core is beyond the reach of rational persuasion even via benefit cuts.

These are of course empirical questions and open to testing. I suspect the third assumption is true. It’s hard to see how someone who believes the entire medical profession and research sector is either corrupt, inept, or both, or that government and media deliberately hide “the Truth”, would ever be persuaded by evidence from just those sources.

A few antivaxxers even believe the germ theory of disease itself is false. In such cases no amount of time spent with a GP explaining the facts is going to help.

They base their “choices” on beliefs ranging from the ridiculous to the repugnant, but their fundamental objection is that the new policies are coercive.

In recent years, antivax activists have tended to frame their objections to legislation like No Jab, No Pay in terms of individual rights and freedom of choice.

Yes, they base their “choices” on beliefs ranging from the ridiculous to the repugnant (including the claim that Shaken Baby Syndrome is really the result of vaccination not child abuse), but their fundamental objection is that the new policies are coercive. They make the medical procedure of vaccination compulsory, which they regard as a violation of basic human rights.

Part of this isn’t in dispute – these measures are indeed coercive. Whether they amount to compulsory vaccination is a more complex question. In my view they do not, because they withhold payments rather than issuing fines or other sanctions, although that can still be a serious form of coercive pressure. Such moves also have a disproportionate impact on families who are less well-off, revealing a broader problem with using welfare to influence behaviour.

Nonetheless, it’s not particularly controversial that the state can use some coercive power in pursuit of public health goals. It does so in a range of cases – from taxing cigarettes to fining people for not wearing seatbelts. Of course there is plenty of room for disagreement about how much coercion is acceptable. Recent discussion in Canberra about so-called “nanny state” laws reflects such debate.

But vaccination doesn’t fall into the nanny state category because vaccination decisions aren’t just made by and for individuals. Several different groups rely on herd immunity to protect them. Herd immunity can only be maintained if vaccination rates within the community are kept at high levels. By refusing to contribute to a collective good they enjoy, vaccine refusers provide a classic example of the Free Rider Problem.

No Jab, No Pay legislation is not about people making vaccination decisions for themselves, but on behalf of their children. The suggestion that parents have some sort of absolute right to make health decisions for their children just doesn’t hold water. Children aren’t property, nor are our rights to parent our children how we see fit absolute. No-one thinks the choice to abuse or starve one’s child should be protected, for example.

And that gives lie to the “pro-choice” argument against these laws – not all choices deserve respect.

The suggestion that parents have some sort of absolute right to make health decisions for their children just doesn’t hold water. Children aren’t property, nor are our rights to parent our children how we see fit absolute.

Thinking in a vacuum

The pro-choice argument depends on the unspoken assumption there is room for legitimate disagreement about the harms and benefits of vaccination. That gets us to the heart of what motivates a great deal of anti-vaccination activism – the issue of who gets to decide what is empirically true.

Antivax belief may play on the basic human fears of hesitant parents but the specific contents of those beliefs don’t come out of nowhere. Much of it emerges from what sociologists have called the “cultic milieu” – a cultural space that trades in “forbidden” or “suppressed” knowledge. This milieu is held together by a common rejection of orthodoxy for the sake of rejecting orthodoxy. Believe whatever you want – so long as it’s not what the “mainstream” believes.

This sort of epistemic contrarianism might make you feel superior to the “sheeple”, the unawake masses too gullible, thick or corrupted to see what’s really going on. It might also introduce you to a network of like-minded people who can act as a buffer from criticism. But it’s also a betrayal of the social basis of knowledge – our radical epistemic interdependency.

The thinkers of the Enlightenment bid us sapere aude, to “dare to know” for ourselves. Knowledge was no longer going to be determined by religious or political authority, but by capital-r Reason. But that liberation kicked off a process of knowledge creation that became so enormous specialisation was inevitable. There is simply too much information now for any one of us to know it all.

Talk to antivaxxers and it becomes clear they’re stuck on page one of the Enlightenment project. As Emma Jane and Chris Fleming have recently argued, adherence to an Enlightenment conception of the individual autonomous knower drives much conspiracy theorising. It’s what happens when the Enlightenment conception of the individual as sovereign reasoner and sole source of epistemic authority confronts a world too complex for any individual to understand everything.

As a result of this complexity we are reliant on the knowledge of others to understand the world. Even suspicion of individual claims, persons, or institutions only makes sense against massive background trust in what others tell us.

Accepting the benefits of science requires us to do something difficult – it requires us to accept the word of people we’ve never met who make claims we can never fully assess.

Accepting the benefits of science requires us to do something difficult – something nothing in our evolutionary heritage prepares us to do. It requires us to accept that the testimony of our direct senses no longer has primary authority. And it requires us to accept the word of people we’ve never met who make claims we can never fully assess.

Anti-vaxxers don’t like that loss of authority. They want to think for themselves, but they don’t accept we can’t think in a vacuum. We do our thinking against the background of shared standards and processes of reasoning, argument and testimony. Rejecting those standards by making claims that go against the findings of science without using science isn’t “critical thinking”. No more than picking up the ball and throwing it is “better soccer”.

This point about authority tells us something ethically important too. Targeting the vaccine-hesitant rather than the hard core refusers makes a certain kind of empirical sense.

But it’s important to remember the hard core are the source of the misinformation that misleads the hesitant. In the end, the harm caused by antivax beliefs is due to people who abuse the responsibility that comes with free speech. Namely, the responsibility to only say things you’re entitled to believe are true.

Most antivaxxers are sincere in their beliefs. They honestly do think they’re doing the right thing by their children. That these beliefs are sincere, however, doesn’t entitle them to respect and forbearance. William Kingdon Clifford begins his classic 1877 essay The Ethics of Belief with a particularly striking thought experiment.

A shipowner was about to send to sea an emigrant-ship. He knew that she was old, and not well built at the first; that she had seen many seas and climes, and often had needed repairs. Doubts had been suggested to him that possibly she was not seaworthy. These doubts preyed upon his mind and made him unhappy; he thought that perhaps he ought to have her thoroughly overhauled and refitted, even though this should put him at great expense. Before the ship sailed, however, he succeeded in overcoming these melancholy reflections.

He said to himself that she had gone safely through so many voyages and weathered so many storms that it was idle to suppose she would not come safely home from this trip also. He would put his trust in Providence, which could hardly fail to protect all these unhappy families that were leaving their fatherland to seek for better times elsewhere. He would dismiss from his mind all ungenerous suspicions about the honesty of builders and contractors.

In such ways he acquired a sincere and comfortable conviction that his vessel was thoroughly safe and seaworthy; he watched her departure with a light heart, and benevolent wishes for the success of the exiles in their strange new home that was to be; and he got his insurance-money when she went down in mid-ocean and told no tales.

Note that the ship owner isn’t lying. He honestly comes to believe his vessel is seaworthy. Yet Clifford argues, “the sincerity of his conviction can in no way help him, because he had no right to believe on such evidence as was before him.”

In the 21st century nobody has the right to believe scientists are wrong about science without having earned that right through actually doing science. Real science, mind you, not untrained armchair speculation and frenetic googling. That applies as much to vaccination as it does to climate change, GMOs and everything else.

We can disagree about the policy responses to the science in these cases. We can also disagree about what financial consequences should flow from removing non-medical exemptions for vaccination refusers. But removing such exemptions sends a powerful signal.

We are not obliged to respect harmful decisions grounded in unearned beliefs, particularly not when this harms children and the wider community.