Omertà implies "the categorical prohibition of cooperation with state authorities or reliance on its services, even when one has been victim of a crime." A person should absolutely avoid interfering in the business of others and should not inform the authorities of a crime under any circumstances, but if it is justified, he may personally avenge a physical attack on himself or on his family by vendetta, literally a taking of revenge, a feud. Even if somebody is convicted of a crime that he has not committed, he is supposed to serve the sentence without giving the police any information about the real criminal, even if the criminal has nothing to do with the Mafia. Within Mafia culture, breaking "omertà" is punishable by death. "Omertà" is an extreme form of loyalty and solidarity in the face of authority. One of its absolute tenets is that it is deeply demeaning and shameful to betray even one's deadliest enemy to the authorities. For that reason, many Mafia-related crimes go unsolved. Observers of the Mafia debate whether omertà should best be understood as an expression of social consensus for the Mafia or whether it is instead a pragmatic response based primarily on fear, as implied by a popular Sicilian proverb "Cu è surdu, orbu e taci, campa cent'anni 'mpaci" ("He who is deaf, blind and silent will live a hundred years in peace"). It has also been described as follows: "Whoever appeals to the law against his fellow man is either a fool or a coward. Whoever cannot take care of himself without police protection is both. It is as cowardly to betray an offender to justice, even though his offences be against yourself, as it is not to avenge an injury by violence. It is dastardly and contemptible in a wounded man to betray the name of his assailant, because if he recovers, he must naturally expect to take vengeance himself." Omertà is a code of silence, according to one of the first Mafia researchers Antonio Cutrera, a former officer of public security. It seals lips of men even in their own defense and even when the accused is innocent of charged crimes. Cutrera quoted a native saying which was first uttered (as goes the legend) by a wounded man to his assailant: "If I live, I'll kill you. If I die, I forgive you." Sicilians adopted the code long before the emergence of Cosa Nostra, and it may have been heavily influenced by centuries of state oppression and foreign colonisation.