Burden of Proof
Not disproven is not the same as proven.
What it is
This flaw treats a lack of evidence as proof. 'No one has disproven it, so it must be true' is the classic form.
It also appears as shifting the burden: demanding the other side disprove a claim instead of proving it. Whoever makes the claim carries the burden.
An LSAT-style example
This example is original. It is not a real LSAT question.
No study has proven the new supplement is unsafe. Therefore it is safe.
The flaw: The absence of proof against the supplement is not proof it is safe. The claim still needs positive evidence.
How to spot it on test day
- Watch for 'no one has shown,' 'cannot be disproven,' 'prove me wrong.'
- Ask: who made the claim? That person owes the evidence.
- Ignorance is symmetric: not proven false is not proven true.
The right answer vs. the trap
The right answer
The correct answer says the argument treats the absence of counterevidence as positive proof.
The trap
The trap may debate how much evidence is enough. The flaw is treating zero evidence as sufficient.
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