Classical jurists held that human reason is a gift from God which should be exercised to its fullest capacity. However, they believed that use of reason alone is insufficient to distinguish right from wrong, and that rational argumentation must draw its content from the body of transcendental knowledge revealed in the Quran and through the sunnah of Muhammad.
Sources Primary Quran In Islam, the
Quran is considered to be the most sacred source of law. Classical jurists held its textual integrity to be beyond doubt on account of it having been handed down by many people in each generation, which is known as "recurrence" or "concurrent transmission" (
tawātur). Only several hundred verses of the Quran have direct legal relevance, and they are concentrated in a few specific areas such as inheritance, though other passages have been used as a source for general principles whose legal ramifications were elaborated by other means.
Hadith The body of
hadith provides more detailed and practical legal guidance, but it was recognized early on that not all of them were authentic. Early Islamic scholars developed a methodology for evaluating their authenticity by assessing trustworthiness of the individuals listed in their transmission chains. These criteria narrowed down the vast corpus of prophetic traditions to several thousand "sound" hadiths, which were collected in several canonical compilations. The hadiths which enjoyed concurrent transmission were deemed unquestionably authentic; however, the vast majority of hadiths were handed down by only one or a few transmitters and were therefore seen to yield only probable knowledge. The uncertainty was further compounded by ambiguity of the language contained in some hadiths and Quranic passages. Disagreements on the relative merits and interpretation of the textual sources allowed legal scholars considerable leeway in formulating alternative rulings.
Secondary Ijmā' Consensus (
ijma) could in principle elevate a ruling based on probable evidence to absolute certainty. This classical doctrine drew its authority from a series of hadiths stating that the Islamic community could never agree on an error. This form of consensus was technically defined as agreement of all competent jurists in any particular generation, acting as representatives of the community. However, the practical difficulty of obtaining and ascertaining such an agreement meant that it had little impact on legal development. A more pragmatic form of consensus, which could be determined by consulting works of prominent jurists, was used to confirm a ruling so that it could not be reopened for further discussion. The cases for which there was a consensus account for less than 1 percent of the body of classical jurisprudence.
Qiyās and 'aql Analogical reasoning (
qiyas) is used to derive a ruling for a situation not addressed in the scripture by analogy with a scripturally-based rule. In a classic example, the Quranic prohibition of drinking wine is extended to all intoxicating substances, on the basis of the "cause" (
ʿilla) shared by these situations, which in this case is identified to be intoxication. Since the cause of a rule may not be apparent, its selection commonly occasioned controversy and extensive debate. Twelver Shia jurisprudence does not recognize the use of qiyās, but relies on reason (
ʿaql) in its place.
Ijtihād The classical process of
ijtihād combined these generally recognized principles with other methods, which were not adopted by all legal schools, such as
istiḥsān (juristic preference),
istiṣlāḥ (consideration of public interest) and
istiṣḥāb (presumption of continuity). A jurist who is qualified to practice ijtihad is known as a
mujtahid. The use of independent reasoning to arrive at a ruling is contrasted with
taqlīd (imitation), which refers to following the rulings of a mujtahid. By the beginning of the 10th century, development of Sunni jurisprudence prompted leading jurists to state that the main legal questions had been addressed and the scope of ijtihad was gradually restricted. From the 18th century on, leading Muslim reformers began calling for abandonment of taqlid and renewed emphasis on ijtihad, which they saw as a return to the vitality of early Islamic jurisprudence.
Decision types Sharia rulings fall into one of five categories known as "the five rulings" (
al-aḥkām al-khamsa):
mandatory (
farḍ or
wājib),
recommended (
mandūb or
mustaḥabb),
neutral (
mubāḥ),
discouraged (
makrūh), and
forbidden (
ḥarām). It is a sin or a crime to perform a forbidden action or not to perform a mandatory action. Reprehensible acts should be avoided, but they are not considered to be sinful or punishable in court. Avoiding reprehensible acts and performing recommended acts is held to be subject of reward in the afterlife, while neutral actions entail no judgement from God. Jurists disagree on whether the term
ḥalāl covers the first three or the first four categories. The legal and moral verdict depends on whether the action is committed out of necessity (
ḍarūra).
Maqasid and maslaha Maqāṣid (aims or purposes) of sharia and
maṣlaḥa (welfare or public interest) are two related classical doctrines which have come to play an increasingly prominent role in modern times. They were first clearly articulated by
al-Ghazali (d. 1111 C.E/ 505 A.H), who argued that
maslaha was God's general purpose in revealing the divine law, and that its specific aim was preservation of five essentials of human well-being: religion, life, intellect, offspring, and property. Although most classical-era jurists recognized
maslaha and
maqāsid as important legal principles, they held different views regarding the role they should play in Islamic law. Some jurists viewed them as auxiliary rationales constrained by scriptural sources and analogical reasoning. Others regarded them as an independent source of law, whose general principles could override specific inferences based on the letter of scripture. While the latter view was held by a minority of classical jurists, in modern times it came to be championed in different forms by prominent scholars who sought to adapt Islamic law to changing social conditions by drawing on the intellectual heritage of traditional jurisprudence. These scholars expanded the inventory of
maqāsid to include such aims of sharia as reform and women's rights (
Rashid Rida); justice and freedom (
Mohammed al-Ghazali); and human dignity and rights (
Yusuf al-Qaradawi). ==Schools of law==