Card 11 of 24 · Presumption
Onus probandi (shifting the burden)
Claim it, then make everyone else carry the backpack.
If you’re making the claim, it’s generally your job to provide the evidence.
Example
“There’s a hidden tunnel under Donner Summit. Prove there isn’t.”
From the legal maxim onus probandi incumbit ei qui dicit — “the burden of proof lies on the one who asserts.” Closely linked to argumentum ad ignorantiam.
Diagnosis: Absence of disproof is not proof. P2 shifts the evidential load from the asserter to the doubter without justification.
Both sides do this: “You can’t disprove God, so God exists” and “You can’t prove God, so atheism is the default.” Each must argue for its own claim; agnosticism, not atheism, is the neutral position on lack of evidence.
“Prove that Paul didn’t write Ephesians.” Whoever claims authorship either way should present the linguistic and historical evidence.
Reformed epistemology (Plantinga) argues some beliefs are properly basic — a sophisticated claim about where burdens lie, which itself requires argument.
Trail recovery
Clarify who is claiming what. Often both parties are making claims; agree on what each needs to show. In writing, explicitly accept the burden for your thesis.
Try saying: “Let’s each lay out what we’re claiming and what would count as good evidence for it.”
Keep questioning. Keep exploring.