They find out some "end" in the punishment, for instance, revenge and deterrence, and then in all their innocence set this end at the beginning, as the causa fiendi of the punishment, and-they have done the trick.
zigorrean edonolako "helburu" bat aurkitzen dute, adibidez, mendekua edo larderia, gero zabartasunez hasieran jartzen dute helburu hori, zigorraren causa fiendi [kausa egile] gisa eta-kito.