The Shi‘i Innovation in Fourfold Classification of Hadiths (Critique of the Idea of Adopting from Sunnites)

Throughout history, the Shiite researchers of hadith have made use of the fourfold classification of hadiths (ṣaḥīḥ, ḥasan, muwaththaq, and ḍa'īf, literally meaning 'right', 'good', 'authentic', and 'weak' respectively) for distinguishing types of hadiths. Although a large number of scholars have accepted this classification, some others – such as Astarabadi – have regarded it a kind of heresy modeled on the Sunnites, leading to ruin of Islam. In this study, we have used the library documents and the descriptive- analytical method for analyzing the contents. Accordingly, the findings of the study are as follows: the aforementioned claim is not acceptable and the existence of similar terminologies, sometimes with more variety for the later Shiites, does not mean that forging scientific terms is accompanied by heresy, and the foundations of the two denominations are different. On the other hand, adding two other terminologies, i.e. "strong" and "authentic" to the threefold classification of the Sunnite scholars – which is resulted from the expertise of the Shiite thinkers – makes the accusation of adopting [from the Sunnites] unacceptable.