Scholars differ over how best to describe these governments, and the vague, sporadic quality of the evidence allows for wide disagreements. Some emphasize the central role of the assemblies and thus tout them as democracies; other scholars focus on the upper-class domination of the leadership and possible control of the assembly and see an oligarchy or an aristocracy. Despite the assembly's obvious power, it has not yet been established whether the composition and participation were truly popular. The first main obstacle is the lack of evidence describing the popular power of the assembly. This is reflected in the "Arthashastra", an ancient handbook for monarchs on how to rule efficiently. It contains a chapter on how to deal with the "sangas", which includes injunctions on manipulating the noble leaders, yet it does not mention how to influence the mass of the citizens—a surprising omission if democratic bodies, not the aristocratic families, actively controlled the republican governments. Another issue is the persistence of the four-tiered Varna class system. The duties and privileges on the members of each particular caste—rigid enough to prohibit someone sharing a meal with those of another order—might have affected the roles members were expected to play in the state, regardless of the formality of the institutions. A central tenet of democracy is the notion of shared decision-making power. The absence of any concrete notion of citizen equality across these caste system boundaries leads many scholars to claim that the true nature of "ganas" and "sanghas" is not comparable to truly democratic institutions.