The Islamic Science of Hadith (in Arabic 'ilm al-hadith علم الحديث) is the Islamic study of hadith, their sources, their narrations, and how much they can be relied upon as a source of religious truth. The traditional Sunni study of hadith attempts to establish the relative trustworthiness of various different hadith by studying the chains of narration (called an isnaad إسناد plural asaanid أسانيد) that are attached to the text of the hadith (the actual text of the saying of the prophet being called a matn متن). By evaluating the plausibility of a given chain of narrators, and the known facts of the narrator's religiousity, trustworthiness, and orthodoxy, Sunni hadith science claims that the veracity of a given saying of the prophet can be determined with absolute certainty. Hadiths recieve grades from the tradents (known in Arabic as muhadiththun محدثون) based off of these criteria, the grades being Sahih (صحيح), Hasan(حسن), Mawdu'(موضوع), and Da'if(ضعيف), with sahih being the highest grade and da'if the weakest. The Sunni tradition generally agrees that all of the hadith of Sahih Al-Bukhari and Sahih Muslim are hadith but beyond this almost all other books of hadith contain hadith which are disagreed upon in the nature of their hadith. The various traditional schools of jurisprudence as well as the salafis have different scholars who have given different ratings to various hadith. Some prominent muhadiththun such as the salafi Shaykh Al-Albani enjoy widespread esteem in the Muslim community, and their judgements on which hadith are sahih and otherwise fit for usage in religious ruling enjoy wide acceptance.

Defining Hadith

A hadith is the saying of the prophet. The hadith has two components, the matn (متن), or the actual saying of the prophet, and the isnad (إسناد), or the chain of narration. The matn can be a recording of something the prophet did, and often includes a story or background information on when and why the prophet said or did what is recorded. The isnad includes the person who allegedly saw or heard the events transcribed.

Defining Isand

Isnads give the chain of transmitters (called in Arabic a raawi راوي plural ruaah رواة) who relate the events up until the time they are written down. A hadith must have an isnad to be considered at all authoritative in the Sunni Islamic tradition. Amongst the basic criteria for isnads, they must include a person at the end who could have reasonably been around the prophet to relate the given information, and the chain of narrators must include only contiguous people who were alive at the same time, so given isnad cannot be considered in any way authentic if one of the persons in the chain died before the person they supposedly relayed the information to was born.

Defining transmitter

Transmitters are the individual links in the chain of isnad. They are the individuals who carry the report through history to the one who ends up writing it down. The origins of the hadith are the companions who would (theoretically) have been around the prophet at the time he did and said the things which are recorded. According to the (unquestioned) presuppositions of the Islamic science of hadith, the companions and their followers and their followers after them more or less instantaneously recognized that the deeds and words of the prophet would be a sunnah or tradition that would form the basis of religious authority in Islam, and immediately set about setting up a culture of oral transmission and recorded isnads so that the veracity of these hadith reports could be

Grades of Hadith and their Usage=

The grades of a given hadith can be Sahih (صحيح), Hasan(حسن), Mawdu'(موضوع), and Da'if(ضعيف). Sahih are considered the carry religious authority second only to the Qur'an itself, but hasan hadith may also be used for religious rulings. Mawdu' and da'if hadith cannot be the basis of rulings but can be referenced for general religious inspiration, although many Muslims disapprove of using them even in this circumspect fashion.

Criterion of Grades

Each of the transmitters in a given chain is evaluated his piety, thruthfullness, and orthodox. A transmitter who lacks in any of these areas will be judged as lacking, and the chain likewise will be downgraded. A given hadith can achieve a higher status, though, if there are mutlipe chains of transmission which attest to the same matn, assuming that most of the trannsmitters in the chain are reliable.

Modern Criticism

Main article:Criticism of Islamic Hadith Science

Modern critical scholarship takes a generally dim view of the usefulness of the Islamic science. The underlying assumptions, that the companions of the prophet and their followers immediately understood the religious importance of hadith as did medeival Muslim jurists, that there was immediately in the aftermath of the prophet's death a reliable culture of oral transmission and hadith preservation, and that the orthodoxy and religiousity or even the reported trustworthiness of a given transmitter tell us about the quality of the transmission are all dismissed by modern scholarship. Scholars, in fact, find significant evidence that the Sunnah of the prophet did not achieve its later importance until after the Rashidun and Ummayyad caliphates. If hadith were not seen as important, it stands to reason that people would not have devoted considerable amounts of time in that era to preservation of hadith, Morover, from the study of Christianity, Judaism, and other religions we know that very religious transmitters are not above fabricating religious material; in fact, quite the opposite seems to be true. As such the grades given to hadith by the traditional Islamic scholars hold little to no value in the eyes of modern critical scholars.