Refuting a claim by deriving a plainly false consequence from it.
A valid form, distinct from the fallacy of caricature. Euclid's proof that there is no largest prime is the classic: assume one exists, construct a larger, and the assumption dies.
In practice
- A claim that any delay is unacceptable is tested by asking about a delay of one second, and the claimant supplies a threshold they had denied having.
- A policy proposal is tested by asking what it implies at scale, and it implies something its author rejects.
- Standing
- A valid form, distinct from the fallacy of caricature.
- Further reading
- Wikipedia
- Subject
- Decision-making & Reasoning
- Essay
- Razors, rules and the tools of careful thought