Actually the aphorism is that it's not possible to prove a negative (and even that is sometimes wrong). Proving that things are impossible is done all the time... it is the basis, for example, of reductio absurdum or proof by contradiction.

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## Umm...

Actually the aphorism is that it's not possible to prove a negative (and even that is sometimes wrong). Proving that things are impossible is done all the time... it is the basis, for example, of reductio absurdum or proof by contradiction.