Rural collective oaths express group commitment rather than factual accuracy

Evidence

In the towns, at least at the top, there is something which does more closely approximate to the Islam of the learned theologians: an exclusive unitarianism with a hidden deity, which proscribes mediation, and so theoretically recognizes no clergy, and which preaches an ethic of rules rather than of loyalty. It neither expresses the cohesion of groups, nor provides an idiom of treachery. The difference in style is well reflected in how you testify at court. The country folk testify in groups in collective oath. Under proper Muslim law, you testify as an individual. The collective oath of the tribesmen is really an expression of commitment to the group, an expression of a willingness to bear responsibility with it. It is not a testimony to matters of factual accuracy, which is the purpose of the oath offered by the individual in an urban trial. — Diego Gambetta, Trust - Making and Breaking Cooperative…, 2007

Categorization

• DEFINE: Contrasts group-based responsibility (collective oath) with individual factual testimony under urban religious style.
• XREF: Connects to formal/informal enforcement distinction in the trading-bourse material: group reputation and accountability vs. individual factual proof.