Backwards. Mob rule is the absence of law.
"And this is that, and that only, which did or could give beginning to any lawful government in the world." -- John Locke"
Anarchy is the abscence of law. Mob rule is not a synonym for anarchy. Therefore mob rule is not the abscence of law. Mob rule is a controlling rule, guided by the motivations of the controlling group, without regard to any general principles concerning the interests of others. Anarchy is a social condition where there is no definite ruler, controlling group, or authority.
Without placing conditions and constraints upon the Locke quote in 178. That collection of freemen establishing rule, could be a mob. As occurred in the French Revolution. Rule has the power of law, so long as the rulers exert themselves and are not successfully unopposed.