The Prohibition of Using Khabar Al-Ahad in Matters of Aqida
Zaydi Usul · Reports and knowledge
The Prohibition of Using Khabar al-Āḥād in Matters of ʿAqīda
Two statements from major Zaydi authorities — Abū Ṭālib al-Hārūnī (d. 424 AH) and al-Qāḍī Jaʿfar ibn ʿAbd al-Salām (d. 573 AH) — on the distinction between solitary reports (akhbār al-āḥād) and knowledge (ʿilm), and why such reports cannot independently establish matters belonging to the foundations of religion (uṣūl al-dīn).
A recurring question in Islamic legal theory is not simply whether a transmitted report should be accepted, but what kind of conclusion that report is capable of establishing.
For these two Zaydi authorities, this distinction becomes decisive when moving from practical rulings to matters of doctrine. A solitary report (khabar al-wāḥid) may have a place in matters of practice (ʿamal), but the foundations of religion (uṣūl al-dīn) require knowledge (ʿilm). If a particular form of report does not yield knowledge, it cannot by itself serve as the basis for establishing such doctrines.
Al-Qāḍī Jaʿfar states the principle directly. More than a century earlier, Abū Ṭālib al-Hārūnī applies essentially the same epistemic distinction when rejecting an argument founded upon an āḥād report.
Two statements
Statement 1 of 2
Al-Qāḍī Jaʿfar ibn ʿAbd al-Salām (d. 573 AH)
A solitary report in the foundations of religion
Arabic
مسألة: خبر الواحد إذا ورد في أصول الدين لم يؤخذ به؛ والدليل على ذلك أن الواجب في أصول الدين هو المصير إلى العلم؛ وخبر الواحد لا يوجب العلم فلم يؤخذ به.
Translation
A solitary report (khabar al-wāḥid), when it concerns the foundations of religion (uṣūl al-dīn), is not relied upon.
The proof of this is that what is obligatory in the foundations of religion is to attain knowledge (ʿilm). A solitary report does not yield knowledge (lā yūjibu al-ʿilm), and therefore it is not relied upon.
Comment — Here the argument is concise and explicitly epistemological. The relevant standard for uṣūl al-dīn is ʿilm — knowledge. Al-Qāḍī Jaʿfar then denies that khabar al-wāḥid produces that degree of epistemic certainty. The conclusion follows from those two premises: it cannot serve as the basis for establishing the foundations of religion.
Statement 2 of 2
Abū Ṭālib Yaḥyā ibn al-Ḥusayn al-Hārūnī (d. 424 AH)
Solitary reports belong to matters of practice
Arabic
والجواب عن الثالث: أن الخبر المروي في ذلك من أخبار الآحاد، وليس هو مما طريقه العلم، والخبر الذي لا يوجب العلم ولا يقطع على صحته لا يجوز قبوله في هذا الباب، لأنه من قبيل الديانات لا من قبيل العمل، وخبر الواحد إنما يسوغ قبوله فيما هو من باب العمل، وهذا كاف في إسقاط احتجاجهم به.
Translation
The answer to the third [argument] is that the report transmitted concerning this is one of the solitary reports (akhbār al-āḥād), and it is not something whose epistemic basis is knowledge (ʿilm).
A report that does not yield knowledge (lā yūjibu al-ʿilm), and whose authenticity cannot be affirmed with certainty (lā yuqṭaʿu ʿalā ṣiḥḥatihi), may not be accepted in this subject, because this belongs to matters of religion or doctrine (diyānāt), not to matters of practice (ʿamal).
A solitary report (khabar al-wāḥid) may be accepted only in matters belonging to the domain of practice (bāb al-ʿamal). This is sufficient to invalidate their argument based upon it.
The shared principle
Read side by side, the two passages rest on the same distinction: not every proof that can ground practice can ground doctrine.
Al-Qāḍī Jaʿfar expresses the rule through the category of the foundations of religion (uṣūl al-dīn). What is required there is ʿilm — knowledge — whereas the solitary report (khabar al-wāḥid) does not, in his formulation, “necessitate knowledge” (lā yūjibu al-ʿilm).
Abū Ṭālib makes the distinction still more explicit. He contrasts matters of religion or doctrine (diyānāt) with matters of practice (ʿamal). An āḥād report that neither produces knowledge nor permits certainty regarding its authenticity cannot establish the former. He then states positively where such a report may function: “A solitary report may be accepted only in matters belonging to the domain of practice.”
This is therefore not, in these passages, a blanket rejection of solitary reports. The issue is the epistemic burden of the subject under discussion. The two authors distinguish between accepting a report as a basis for practical action and treating that same type of report as sufficient to establish a matter requiring knowledge.
“Where knowledge is required, evidence that does not yield knowledge is insufficient.” — the principle in the two passages
Knowledge and action
The vocabulary used by both authors makes the distinction especially clear.
ʿIlm (علم) is knowledge. Al-Qāḍī Jaʿfar says that uṣūl al-dīn require arriving at ʿilm. Abū Ṭālib likewise describes the disputed report as something that does not yield ʿilm and whose authenticity cannot be affirmed decisively.
Khabar al-wāḥid (خبر الواحد), or in the plural akhbār al-āḥād (أخبار الآحاد), is the solitary report. In these passages, its limitation is not that it has no evidentiary role whatsoever, but that it does not provide the kind of knowledge demanded in doctrinal questions.
ʿAmal (العمل) is practice or action. Abū Ṭālib explicitly identifies this as the sphere in which accepting khabar al-wāḥid is permissible.
The result is a hierarchy of evidentiary demands: a proof may be sufficient to govern what one does without necessarily being sufficient to establish what one must claim to know as a foundation of religion.
That distinction is already stated clearly by Abū Ṭālib al-Hārūnī in the fifth century AH and appears again in the later formulation of al-Qāḍī Jaʿfar ibn ʿAbd al-Salām. Despite the difference in wording, the principle expressed in the two cited passages is remarkably direct: where knowledge is required, evidence that does not yield knowledge is insufficient.
O God, send blessings and peace upon Muhammad and the family of Muhammad.
Sources — Abū Ṭālib Yaḥyā ibn al-Ḥusayn al-Hārūnī (d. 424 AH). al-Mujzī fī uṣūl al-fiqh. Edited by ʿAbd al-Karīm Jadbān, 2013, vol. 2, p. 42.
Jaʿfar ibn Aḥmad ibn ʿAbd al-Salām ibn Abī Yaḥyā (d. 573 AH). Al-Taqrīb fī uṣūl al-fiqh. Edited by al-Murtaḍā ibn Zayd al-Maḥaṭwarī al-Ḥasanī (Ṣanʿāʾ: Maktabat Badr lil-Ṭibāʿa wa-al-Nashr wa-al-Tawzīʿ, 2017), p. 80.