Hadith sciences ( ʻilm al-ḥadīth "science of hadith") consists of several religious scholarly disciplines used by Muslim scholars in the study and evaluation of the hadith. ("Science" is used in the sense of a field of study, not to be confused with following the principles of observation and experiment, developing falsifiable hypotheses, etc. of modern science.) The hadith are what most Muslims believe to be a record of the words, actions, and the silent approval of the Islamic prophet Muhammad as transmitted through chains of narrators.An Introduction to the Science of Hadith, translated by Eerik Dickinson, from the translator's introduction, p. xiii, Garnet publishing, Reading, U.K., first edition, 2006. Hadith sciences scholars have aim to determine which of these records are authentic, and which may be fabricated.

For most Muslims, determining authenticity of hadith is enormously important in Islam because along with the Quran, the Sunnah of the Islamic prophet—his words, actions, and the silent approval—are considered the explanation of the divine revelation (wahy), and the record of them (i.e. hadith) provides the basis of Islamic law (Sharia). In addition, while the number of verses pertaining to law in the Quran is relatively few, hadith, for many, give direction on everything from details of religious obligations (such as Ghusl or Wudu, ablutionsAn-Nawawi, Riyadh As-Salihin, 1975: p.203 for salat prayer), to the correct forms of salutations,An-Nawawi, Riyadh As-Salihin, 1975: p.168 and the importance of benevolence to slaves.An-Nawawi, Riyadh As-Salihin, 1975: p.229 Thus the "great bulk" of the rules of Islamic law are derived from hadith, along with the Quran as a primary source.

There are three primary ways to determine the authenticity (sihha) of a hadith: by attempting to determine whether there are "other identical reports from other transmitters"; determining the reliability of the transmitters of the report; and "the continuity of the chain of transmission" of the hadith.

Traditional hadith sciences has been praised by some as "unrivaled, the ultimate in historical criticism", and heavily criticized for failing to filter out a massive amount of hadith "which cannot possibly be authentic". However, both Muslims and western scholars have criticised the hadith. Quranists reject the authority of the hadiths, viewing them as un-Quranic; some further claim that most hadiths are fabrications (pseudepigrapha) created in the 8th and 9th century AD, and which are falsely attributed to Muhammad.Aisha Y. Musa, The Qur’anists, Florida International University, accessed May 22, 2013.Neal Robinson (2013), Islam: A Concise Introduction, Routledge, , Chapter 7, pp. 85-89 Many Western scholars consider that few or no hadith can be confidently considered to be the authentic words of Muhammad, and that traditional attempts to determine the authenticity of hadith are flawed due to the potential for the chain of narrators (particularly the earliest parts) to have been fabricated.

Definition The science of hadith has been described by one hadith specialist, Jalal al-Din al-Suyuti (d. 911 A.H/ 1505 C.E), as the science of the principles by which the conditions of both the sanad (the chain of narration), and the matn (the text of the hadith), are known. This science is concerned with the sanad and the matn with its objective being distinguishing the sahih, authentic, from other than it. Ibn Hajar al-Asqalani said the preferred definition is: knowledge of the principles by which the condition of the narrator and the narrated are determined.Tadrib al-Rawi, vol. 1, pp. 38–9.

History

After the death of Muhammad, his sayings were transmitted orally. According to Islamic tradition, Umar ibn al-Khattab, the second caliph, started the process of collecting all the hadiths together into one unified volume, but gave up the endeavor "for fear the Quran would be neglected by the Muslims" (according to Muhammad Zubayr Siddiqi).

The Umayyad caliph, Umar ibn Abd al-Aziz (aka Umar II, who reigned from 717-720 CE) also started an effort to collect all the hadiths. Teaching and collecting hadiths was part of a plan of his to renew the moral fiber of the Muslim community. He supported teachers of fiqh, sent educators to Bedouin tribes, ordered weekly hadith lectures in the Hejaz, and sent out scholars of hadith to Egypt and North Africa, (according to Muhammad Zubayr Siddiqi).

Umar also ordered the great scholar of Madinah, Abu Bakr ibn Hazm to write down all the hadiths of Muhammad and Umar ibn al-Khattab, particularly those narrated by Aisha. He had these hadiths collected in books which were circulated around the Umayyad Empire. Although these books are lost today, commentaries on them by Ibn al-Nadim reveals that they are organized like books of fiqh, such as the Muwatta of Imam Malik, the first large compilation of hadiths. Imam Malik himself probably followed the general plan of the early books of hadith ordered by Umar.

Hadith sciences developed in part because forgery "took place on a massive scale", with perhaps the most famous collector of hadith and practitioner of ʻilm al-ḥadīth—Muhammad al-Bukhari—sifting through nearly 600,000, over 16 years before eliminating all but approximately 7400 hadith.

Traditional accounts describe "the systematic study of hadith" as being motivated by the altruism of "pious scholars" seeking to correct this problem.Brown, Rethinking tradition in modern Islamic thought, 1996: p.19 Some scholars (Daniel W. Brown, A. Kevin Reinhart) shed doubt on this. Brown believes the theory "fails" to adequately account "for the atmosphere of conflict" of at least early hadith criticism. The "method of choice" of partisans seeking to discredit opposing schools of Islamic law was to discredit the authorities (transmitters) of their opponent's hadith—to "tear apart" their isnads". (To do this required developing biographical evaluations of hadith transmitters—ʿilm al-rijāl and ilm jarh wa ta’dil). Reinhart finds descriptions of famous companions of Muhammad in Ibn Sa'd's Kitāb aṭ-ṭabaqāt al-kabīr "recording hadith and transmitting it, asking each other about precedents, and reproaching those who disregarded this authentic religious knowledge" in suspicious conformity to the "mythology of the pristine early community".

As the criteria for judging authenticity grew into the six major collections of ṣaḥīḥ (sound) hadith (Kutub al-Sittah) in the third century, the science of hadith was described as having become a "mature system", or to have entered its "final stage".

The classification of Hadith into sahih, sound or authentic; hasan, good; da'if, weak, (another rating is mawḍūʿ, fabricated). was utilized early in hadith scholarship by Ali ibn al-Madini (161–234 AH).Ahmad ibn Ali ibn Hajr al-Asqalani, al-Nukat ala Kitab ibn al-Salah, vol. 1, p. 263, Maktabah al-Furqan, Ajman, U.A.E., second edition, 2003 Later, al-Madini's student Muhammad al-Bukhari (810–870) authored a collection, now known as Sahih Bukhari, commonly accepted by Sunni scholars to be the most authentic collection of hadith, followed by that of his student Muslim ibn al-Hajjaj.Ibn Kathir, Ikhtisar Ulum al-Hadith published with explanation al-Ba'ith al-Hathith, vol. 1, pp. 102–3, Maktabah al-Ma'arif, Riyadh, K.S.A., first edition, 1996 Al-Bukhari's methods of testing hadiths and isnads are seen as exemplary of the developing methodology of hadith scholarship.Ibid.

Evaluating authenticity An elaborate system was developed by scholars of hadith to determine the authenticity of traditions based on "two premises": that the authenticity of a hadith report is "best measured by the reliability of the transmitters" (known as rāwī pl. ruwāt) of the report; consequently, "carefully scrutinizing" the "individual transmitters" of the hadith (ilm jarh wa ta’dil; ʿilm al-rijāl) and "the continuity of their chains of transmission" is the best way to measure hadith reliability.

A basic element of hadith sciences consist of a careful examination of the chain of transmission (sanad , also isnād , or silsila ), relaying each hadith from the Prophet to the person who compiles the hadith. The isnād and the commentary are distinct from the matn (), which is the main body, or text, of the hadith,Tadrib al-Rawi, by al-Suyuti vol. 1, pp. 39–41 with abridgement.Hans Wehr, Arabic-English Dictionary, page 752. These two terms are the primary components of every hadith.

According to the person most responsible for elevation of the importance of hadith in Islamic law, Imam Al-Shafi‘i, "In most cases the truthfulness or lack of truthfulness of a tradition can only be known through the truthfulness or lack of truthfulness of the transmitter, except in a few special cases when he relates what cannot possibly be the case, or what is contradicted by better-authenticated information."Al-Shafi'i, al-Risala, Bulaq, 1321; ed. Sheikh Ahmad Muhammad Shakir, Cairo, 1940 (ed. Shakir), 55

The first people who received hadith were Muhammad's "Companions" (Sahaba), who are believed to have understood and preserved it. They conveyed it to those after them as they were commanded; then the generation following them, the "Followers" (Tabi‘un), received it and then conveyed it to those after them, and so on. Thus, the Companion would say, “I heard the Prophet say such and such.” The Follower would say, “I heard a Companion say, ‘I heard the Prophet say’” The one after the Follower would say, “I heard a Follower say, ‘I heard a Companion say, ‘I heard the Prophet say’” and so on.Ilm al-Rijal wa Ahimiyatuh, by Mu'allami, p. 16, Dar al-Rayah. I substituted the word sunnah with the word hadith as they are synonymous in this context.

Criteria to be a ṣaḥīḥ hadith To be 'ṣaḥīḥ ("sound") hadith, an isolated hadith (Mutawatir hadith were exempt from these tests) "must pass five tests": "continuity of transmission"; ʿadāla of transmitters, i.e. transmitters must be of good character; "accuracy (ḍabṭ) of the process of transmission, i.e. narrators must not be prone to carelessness or known to have poor memories"; absence of "irregularities" (shadhūdh), i.e. hadith must not contradict a "more reliable source"; "absence of corrupting defects(ʿilla qādiḥa), i.e. inaccuracies in reporting the actual chain of transmission."

Biographical evaluation

An important discipline within hadith sciences is biographical evaluation, the study of transmitters of hadith, ʿilm al-rijāl, (literally "science of men") mentioned above. These are the narrators who make up the sanad. Ilm ar-rijal is based on certain verses of the Quran.

Transmitters are studied and rated for their "general capacity" (ḍābit; itqān) and their moral character (ʿadāla). General capacity is measured by qualities such as memory, linguistic ability. Transmitters that have good memories and linguistic ability "might be considered competent (ḍābit)". ʿadāla transmitters must be "adult Muslims, fully in control of their mental faculties, aware of their moral responsibilities, free from guilt for major sins, and not prone to minor sins". Examples of ratings of transmitters include "trustworthy" or thiqa for ones that possess both ʿadāla and ḍābit. Transmitters that are ʿadāla but show signs of carelessness are rated honest or ṣudūq. The result of this study were "vast biographical dictionaries" to check against the isnads of individual hadith.

Not all transmitters were evaluated for these characteristics and rated. Companions of the prophet (ṣaḥāba) were traditionally considered to possess collective moral turpitude or taʿdīl, by virtue of their exposure to the Prophet, so that they all possessed ʿadāla without needing to be evaluated. (This quality was similar to that of Prophetic infallibility (ʿiṣma) but of course lower in level.)

The history of the narrators must include four things: Their Isma-ul-Rijjal (biographies) Their kunniyaat (nicknames) Their place of settlement