One of the most significant sources of human knowledge is transmitted knowledge. Transmitted knowledge is defined as any knowledge relayed from one person to another orally or through a written document and is accessed by another person either by hearing it or reading it. The daily news you watch, the personal experiences your friends and family share with you, the information you are relayed at work from your boss, the blogs you are subscribed to and read regularly, or even a customer service representative at a store telling you which aisle a certain product is. In all these cases you are constantly formulating knowledge regarding the world and existence at large based on oral and written transmissions.
One of the most important examples of transmitted knowledge are the ḥadīth (pl. aḥadīth), the traditions and reports attributed to the Prophet (p) and the infallibles (a). In the words of Ayatullah Borūjerdī (d. 1961) the study of ḥadīth is the most noble of disciplines as it is through this discipline that one obeys Allah (swt), learns about His (swt) divine laws, learns the Qurān, its revelation, exegesis and its hidden and concealed meanings. It is through this discipline that one protects the religion, and the pillars of Islam are strengthened. If it were not for the ḥadīth, and those who heard the narrations, memorized them, wrote them down, transmitted them, and took guardianship of them, the pillars of religion would have collapsed, just as the Imam (a) himself affirms when he said, “If there was no Zurārah and others like him, the narrations of my father would have been wiped out."
Given the importance of the ḥadīth, it then only behooves one to have an epistemic framework by which they can judge, ascertain, and verify the report to be an authentic reflection of what the Prophet (p) and the infallibles (a) had imparted. When one comes across transmitted knowledge in their daily life, by what criteria do they judge and ascertain this knowledge? Do they only affirm this transmitted knowledge if they personally attain certainty or a strong conviction after hearing or reading something, or is one’s personal conviction irrelevant and instead the mere fact that a trustworthy figure is informing them of something, or that a report exists in a certain book they trust suffices for them to believe in it and act upon it? While the answers to these and other similar thought-provoking questions are extensively discussed by Muslim scholars, regardless of what you determine as a criterion, one of the key factors that helps one fulfil their criterion is the study and knowledge of individuals who are memorizing, writing, and transmitting the ḥadīth, albeit the need may vary. The particular discipline that studies the qualities of individuals recording and transmitting the ḥadīth, whether they are reliable or not, is called ‘Ilm al-Rijāl, and the discipline that studies the descriptions of the ḥadīth itself, whether they are authentic or unauthentic, is called ‘Ilm al-Dirāyah. While these disciplines can assist us in generally organizing and categorizing the narrators, scribes, authors of various ḥadīth books, and the ḥadith themselves, it is imperative to note that there are technicalities involved in accepting and rejecting a ḥadīth beyond these mere descriptions.
In other words, it is very much possible for one or more transmitters of a ḥadīth to be known as an untrustworthy person, and subsequently for the ḥādīth to be classified as weak, however, when put alongside other similar traditions or in light of other contextual indicators, its content could be attributed to the Prophet (p) or the infallibles (a) with conviction. Likewise, it is very much possible for the transmitters of a ḥadīth to be trustworthy, and subsequently for the ḥadīth to be classified as authentic, yet based on other contextual indicators, one may conclude that its contents cannot be attributed to the Prophet (p) or the infallibles with conviction. In fact, at times the contrary evidence may be strong enough to even conclude that the report was a fabrication.
As an aid for researchers, students and scholars who recognize the significance of the aforementioned questions and discussions, Thaqalayn.net has made a humble effort to publish the gradings of every particular ḥadīth according to the opinion of a number of scholars. For non-specialists, these gradings should be taken with a grain of salt and one should not be inclined to derive any conclusions regarding the narrators or contents of the ḥadīth based on them.
Currently, these include gradings of ‘Allāmah Majlisī (d. 1699) and Shaykh Bāqir Behbūdī (d. 2015) for the aḥadīth in al-Kāfī. And you may also find the gradings of Shaykh Hādī al-Najafī and Shaykh Āṣif al-Moḥsini (d. 2019) sporadically.