—that Muhammad commanded people to perform pilgrimage to a house other than the Ancient House; or that he made fasting in a month other than Ramadan obligatory; or that he instituted a sixth prayer at the mid-morning (duḥā); or that he prescribed the adhān and iqāma for acts other than the five daily prayers;

or that he declared publicly, in the presence of the people, to Abū Bakr, or to al-ʿAbbās, or to ʿAlī, or to anyone else, “This is the caliph after me, so listen to him and obey”;

or that ʿAlī summoned people to recognise his own leadership during the caliphate of the first three. Allegations such as these—had they actually taken place—would have entailed necessary consequences; the absence of those consequences proves the absence of the alleged event. Some of these corollaries are obvious, while others are subtle and known only to the specialists.

Accordingly, scholars versed in the Prophet’s biography decisively pronounce certain ḥadith to be spurious—ḥadith whose falsehood others do not know with certainty—because they recognise the implications those reports would necessarily carry and see that those implications are absent. Thus a person well acquainted with the Prophet’s campaigns knows for certain that he engaged in no fighting during the Tabūk expedition; that the battles involving actual combat numbered only nine; that he never personally campaigned in Yemen or Iraq; that after prophethood he never travelled beyond Tabūk; that after the Hijra he performed no pilgrimage except the Farewell Pilgrimage; and that he fasted only nine Ramadans.

Likewise they recognise that a given transmitter has erred in relating a particular ḥadith from a certain authority, for they know through established evidence that the ḥadith was transmitted in a specific wording. When an unreliable narrator conveys it in a contradictory form, they see its falsity and know that he has either made a mistake or deliberately lied—just as they know the falsehood of the one who added to the Prophet’s statement—