Denying the Antecedent
Denying the antecedent reasons: if P then Q, P is false, so Q must be false. It fails because Q can be true for other reasons. Debaters answer by showing that Q can still happen without P.
Denying the Antecedent as it appears in championship debate rounds. Each example below is a moment from a real round, with a note on why it illustrates the technique and how a debater can use it, or answer it.
Example 1: The speaker answers the opponent's international-abandonment scenario by pointing out a broken inference
The opponent's evidence says migration causes international support, but that does not prove that stopping migration causes international abandonment. This exposes reasoning from 'if A then B' to 'if not A then not B'. Students can use this by checking whether the opponent's card proves the reverse direction their impact actually needs.
Sources: every example links to the YouTube video of the championship debate it comes from, at the moment described.
All techniques and fallacies