This tactic often comes up in discussions related to scientific and religious issues.
It’s usually used by someone who has made a claim and then been asked for evidence to support it. Their response is to demand that you show that the claim is wrong and if you can’t, to insist that this means their claim is true.
Science or Not has a brief article on this at The reversed responsibility response – switching the burden of proof. It says:
“People use this tactic to avoid supplying supporting evidence – usually because there is none. In attempting to distract you from this lack of evidence, they try to convince you that the responsibility of supplying evidence lies with you.”
This can be relatively trivial – a person might claim that there is plenty of evidence that climate change science is a scam or that community water fluoridation (CWF) is harmful. When asked for supporting evidence they ask you to “look it up” or “google it” yourself – implying that you are lazy to even ask then for their supporting evidence.
We can’t prove the impossible
Then there is the philosophically dishonest reversal of responsibility where they demand, for example, the supporter of CWF cite studies showing CWF does not cause harm. Dishonest because that is not how science works – it seeks to test specific situations for harm. One might produce study after study showing no specific harm but it is impossible to design a study showing anything is “safe.” The person can, therefore, dismiss each example showing no specific harm by insisting that this does not prove it is safe in all situations.
“Reversing the burden of proof is a form of the argument from ignorance fallacy, in which it is argued that a claim must be taken as true if it hasn’t been shown to be false.”
Yet, ideologically driven activists will often use this argument – maybe dressed up as the “precautionary principle.” For example, they will make submissions to community bodies conceding that perhaps they cannot produce any decisive studies showing CWF is harmful but the “precautionary principle” means that it should not be used until research shows it to be completely safe.
This is simply using ignorance – on the part of members of the community body as well as the activist – to prevent acceptance of a policy which is recommended by experts and health authorities. It’s an attempt to destroy the authority of evidence and science which should be centrally considered in such decisions.
What to do when confronted by this tactic
The Science or Not article gives advice on how to treat such tactics:
“Don’t be tempted to take on the task of falsifying the perpetrator’s claim. And don’t succumb to the pressure to accept it as true if you don’t have the evidence to refute it. Insist that they must provide supporting evidence from real-world tests.”
On the one hand, this means that community bodies who are offered submissions in this vein should demand the submitters produce the evidence and not rely on vague statements or claims. In particular, they should be wary of the use of “the precautionary principle” – unless there is enough evidence to suggest that it is applicable.
On the other hand, it means that if submitters do produce “evidence” that it must be critically and intelligently examined and not just accepted because it is full of citations. That would be submitting to the “authority” fallacy.
Finally, community bodies should be conscious of their own limitations. If they don’t have the skills for considering presented evidence properly then they should ask for the advice and opinions of real experts about that evidence.