The concept of “the burden of proof” is a matter of interpersonal protocol in debate or discussion. In formal contexts, such as courts of law, one side—in criminal cases in the United States, the prosecution—may hold the burden of proof. Some formal debates also make use of a burden of proof as part of the rules.
A burden of proof fallacy occurs when someone attempts to invoke or assign a burden of proof outside of any agreement or interpersonal protocol.
In such cases, the concept of “the burden of proof” becomes a rhetorical trope that conceals two informal logical fallacies: special pleading and an argument to ignorance. A fallacy of special pleading occurs when one asks or demands (“pleads”) to be exempted from a rule or criterion to which everyone else is held for no relevant reason (or no reason at all). An argument to ignorance fallacy has the form “my assertion is true until proven false.”
The burden of proof fallacy takes the form of “My position is the default position. My opponent has the burden of proof!” But in asserting that one’s position is “the default position”, one is making an argument to ignorance: this just is equivalent to saying “My position is true until it is proven false.” And the justification for this argument to ignorance is simply special pleading that one be allowed to use an argument to ignorance as if it were valid.
Both combined have the form “My argument is true until proven false, and although this is an argument to ignorance, I am specially pleading that I be allowed to use it, despite its invalidity.” This sounds more legitimate when it is phrased as “My position is the default position, and my opponent has the burden of proof,” but the meaning is the same.
To attempt to lay the burden of proof solely on one’s opponent, as if one had some sort of metaphysical, moral, or logical right to do so is logically fallacious, intellectually dishonest, and unethical. Since the burden of proof exists solely as a matter of interpersonal protocol, it cannot be placed upon someone without their consent.
As my readers know, I do not appreciate attempts to obligate me without my consent. As my readers also know, I block this move by demanding that anyone who asserts that I have “the burden of proof” PROVE IT. And he will never be able to do so, since the burden of proof is a matter of interpersonal protocol, and not any sort of metaphysical, logical, or ethical principle. It is exactly the same as someone unilaterally attempting to say that I am bound by a contract I never agreed to or signed, just because he says I am a party to the contract. He cannot “prove” I signed a contract I never signed.
Or to make an even more obvious analogy, it is like someone claiming that of two parties, one of them can consent for the other person, whether or not he or she agrees to this. This dynamic has the same structure as an accused rapist arguing to be acquitted of rape charges on the grounds that he consented for his victim and therefore there was consent.
No one in their right mind would accept this kind of argument. Consent precisely does not occur when only one of the two parties involve does the “consenting” for both. And it is not any more sound when it involves nonconsensual attempts to morally obligate someone with specious “burdens.”