For this reason, uprightness and sinfulness are established through widespread reports, and testimony concerning them is given on that basis, just as all Muslims testify that ʿUmar ibn ʿAbd al-ʿAzīz was just and that al-Hajjāj was unjust.

Justice and injustice are not outwardly observable. What a person observes, for the most part, are actions, just as he hears words. When he sees a man giving or killing, he observes the act itself. But whether the man killed rightfully or wrongfully, or gave justly and benevolently or otherwise, cannot be known through observation alone; reason must also play a part in this knowledge.

The same applies to someone unfamiliar with medicine and grammar. When he encounters the mass-transmitted reports among physicians and grammarians concerning the learning of Hippocrates, Galen, and others like them, and of al-Khalīl and Sībawayh, he knows that these men were learned in medicine and grammar, even though he himself knows neither discipline. The knowledge of those reporting this is not derived from direct observation.

Likewise, when reports about the learning of Mālik, al-Shāfiʿī, Ahmad, Yahyā ibn Maʿīn, al-Bukhārī, Muslim, and others like them in jurisprudence and hadith reach him through mass transmission, he knows that they were learned in these fields, even though those reporting this did not report from direct observation. Rather, experts in jurisprudence and hadith who examine these men’s words know by necessary knowledge that they were learned in these fields. These experts then report this to others.

Thus, these reports reach those others through mass transmission.