PETER HITCHENS: The real cause of knife crime? It’s hidden in a fog of cannabis smoke Does any powerful person in this country ever think? It has been quite astonishing watching the alleged debate about knife crime over the past few days. Not a single thought took place. There is a very good reason why people generally don’t stab each other. Normal, sane humans recoil from the very idea of plunging a sharp blade into a fellow creature, let alone driving it so deep that it is bound to kill.