Hadith report, the scale of the report's transmission, the routes through which the report was transmitted, and the individual narrators involved in its transmission. On the basis of these criteria, various classifications were devised for hadith. The earliest comprehensive work in hadith studies was Abu Muhammad al-Ramahurmuzi's "al-Muhaddith al-Fasil", while another significant work was al-Hakim al-Naysaburi's "Ma‘rifat ‘ulum al-hadith". Ibn al-Salah's "ʻUlum al-hadith" is considered the standard classical reference on hadith studies. By means of hadith terminology, hadith are categorized as "ṣaḥīḥ" (sound, authentic), "ḍaʿīf" (weak), or "mawḍūʿ" (fabricated). Other classifications used also include: "ḥasan" (good), which refers to an otherwise
Criticism of Hadith highly of Mutawatir: However, orthodox hadith scholars find non-mutawatir hadith adequate. "According to the majority of the ulama of the four Sunni schools, acting upon ahad is obligatory even if ahad fails to engender positive knowledge. Thus, in practical legal matters," but not in "matters of belief", "a preferable "zann" [meaning, speculative] "is sufficient as a basis of obligation." Ibn al-Salah ( (d. 643/1245), "one of the most distinguished traditionists of the muta'akhkhirun", argues (according to Farooq), that because mutawatir type hadith is rare, "for much of Islamic praxis, certainty of knowledge is neither feasible nor required. Rather, probable or