What is the term for allowing an implausible scenario in order to be as generous as possible to the claim one is about to knock down? Example:
Acme Acres recorded 2,000 births last year, but the town has only 500 women. Even if they are all of child-bearing age and each had two deliveries last year, it is still virtually impossible that they gave birth to 2,000 babies. Either out-of-towners were flocking to Acme Acres to deliver or the statistic is wrong.
It's a little like "giving the benefit of the doubt" "for the sake of argument", but I don't think "doubt" is the right word here (the allowed scenario is almost certainly false). There should be a precise term or expression from this kind of argumentation, at least a Latin one from law or a Greek one from rhetoric.