Outstanding among the social problems facing urban centers of the world in general and Nigeria is the problem of crime. The increasing rate of criminal activities has become a major concern across the globe. Today, lives and properties are no longer safe for both the rich and the poor. All seem to live one day at a time. Content Analysis is used as the method of data analysis. The method adopted was more of an exposition, critical analysis and evaluation. More specifically, this paper gave a general background about violence, urban violence and the question of self-defense. Furthermore, a philosophical answer was given in the light of the medieval thinker St. Thomas Aquinas. It was concluded that there is a need for social living. A good citizen is one who has an unselfish love for the common good of his state; a love issuing forth in an efficacious desire to see that good is procured and furthered. Thus, a good citizen realizes that he is part of a social and political society. Thus, his personal goodness, and the goodness of his actions contributes to the good of all.