In brief, he says that Setsuninto means definitively killing a wicked person and Katsuninken means saving many people and "bringing them to life".
仇なす悪に打ち勝って確実に殺すのが殺人刀であって、その悪を殺したゆえに万人が救われ「活きる」のが活人剣だと言う。