The Four Sources or al-Adillat al-Arbaʿa (Arabic: الأدلة الأربعة) is a terminology in the principles of jurisprudence referring to the four main sources of ijtihad (deducing the laws of shari'a). These sources consist of the Qur'an, the tradition, consensus, and reason. There are sources of ijtihad that are not reliable in the viewpoint of Shiite Muslims, such as qiyas (analogy), istihsan (juristic preference), and sadd al-dharayi' (blocking the means to evil). The reliability of these four sources is demonstrated in the evidences part of principles of jurisprudence.
Shiite Akhbaris rely only on the Qur'an and the tradition and reject the reliability of consensus and reasoning in deducing the laws of shari'a.
In that it may lead to either a factual or non-factual law:
- Ijtihadi evidence: evidence that demonstrates a real or factual law of shari'a, that is, it makes the real law probable.
- Fiqahati evidence: evidence that does not aim at the real law; rather at what should be done in practice when the real law is not known. This is also called a practical principle (al-Asl al-'Amali). This is called "fiqahati" because it fits the definition of jurisprudence (knowledge of the laws of shari'a).
And with respect to the type of evidence, there is verbal and non-verbal (lubbi) evidence:
- Lubbi (non-verbal) evidence: is what is not of a verbal type, such as consensus, rational practice, and the like.
- Lafzi (verbal) evidence: is of a verbal type, such as hadith or testimony.
- Main article: Qur'an
The Qur'an (the Book) is the first of the four sources. There are about 500 verses of the Qur'an concerned with the verses of rulings. Researchers and scholars have considered the Qur'an in different respects, such as historical, exegetical, theological, and the like. In jurisprudence, verses of rulings are considered, according to their subject. The reliability of the apparent meanings of these verses is discussed in principles of jurisprudence.
Akhbaris rejected the reliability of the apparent meanings of the Qur'an, and this pressed scholars of principles of jurisprudence to bring arguments proving the reliability of the apparent meanings of Qur'an. The first person who expressed reservations with respect to the reliability of the apparent meanings of Qur'anic verses was Muhammad Amin al-Istarabadi. According to his view, since deducing laws of shari'a from the apparent meanings of the Qur'an is probabilistic (zanni) and since in his view, it was necessary to have knowledge by certainty, the apparent meanings of the Qur'an are not reliable for deducing the laws of shari'a.
- Main article: Sunna
By "tradition" here is meant the "words", the "acts", and the "consent" of the Infallibles (a). The extension of this notion is different for Shiite and Sunni scholars. The latter take only the words, the acts, and the consent or endorsement (taqrir) of the Prophet (s) to be the tradition, and the former extend it to those of the Prophet (s), Twelve Imams (a), and Fatima al-Zahra (a).
Types of the tradition:
- Words of the Infallibles (a): the words of the Infallibles (a) that are narrated by tawatur or through one person (al-Khabar al-Wahid). Hadith is sometimes loosely taken to be the tradition, but more precisely speaking, it is only expressive of the tradition.
- Acts of the Infallibles (a): if an Infallible (a) performs an action, it at least reveals the permissibility of the action, and if an Infallible (a) abandons an action, it at last shows that the action is not obligatory. Sometimes their action or omission is accompanied with some evidence that shows something more than permissibility or not being obligatory; for instance, when it is in the context of expressing a law of shari'a. In jurisprudence, there have been many appeals to actions or omissions of the Infallibles (a), such as the laws concerning prayer, wudu, hajj, and so on.
- Consent of the Infallibles (a): by consent is meant a certain sort of silence of an Infallible (a) when confronted with the actions of other people, that is, if someone does something when an Infallible (a) is present and attentive to the action and is in a position to comment on the action but does not do so, then that is evidence of the permissibility of that action, since if the action were not permissible, the Infallible (a) would have informed the person of its wrongness. Therefore, if certain conditions are met, the consent is evidence of the permissibility of an action.
And with respect to the way one can have access to the tradition, it can be classified into certain and non-certain:
- Known by certainty: a tradition discovered by tawatur or otherwise by decisive evidence that it was really issued by the Infallible (a), such as consensus and rational practice that reveal the words of the Infallible (a).
- Not known by certainty: there are various probabilistic means to discover the tradition; these means do not yield certainty, and thus there should be a reason to accept such means. For Imamiyya jurists, only al-Khabar al-Wahid that meets certain conditions is reliable.
- Main article: Consensus
Imamiyya's conception of consensus (ijma') is different from that of Sunni scholars. For Imamiyya, the consensus is not an independent source by itself, rather it goes back to the tradition, since it is reliable insofar as it reveals the view of the Infallibles (a)—a consensus that does nothing by way of revealing the view of the Infallibles (a) is not reliable. Even some jurists maintain that a consensus is reliable only if it is an agreement among a group of jurists where we know that Imam (a) is amongst them. In principles of jurisprudence, distinctions have been made between different types of consensus.
Most scholars of principles of jurisprudence consider the reason to be an independent source of deducing the laws of shari'a along with the Qur'an and the tradition. Though reason has been mentioned in many books in principles of jurisprudence, its notion has not been clarified enough. It is usually taken to be referred to any intellectually known proposition that has implications for certain laws of shari'a.
Correlation between Reason and Shari'a There is a widely accepted principle among most Shiite and some Sunni scholars of principles of jurisprudence to the effect that, "Whatever is affirmed by Shari'a, is also affirmed by the reason, and vice versa," though it has been rejected by Shiite Akhbaris and some Sunni scholars. People who take the reason to be a source for deducing the laws of shari'a accept the correlation principle, and the opponents of the reason as a source of shari'a have rejected the principle of correction.
- Theoretical reason: a law of shari'a can only be decided by the divine legislator. Thus by reason it is meant that the theoretical reason discovers the correlation between what is affirmed by the reason and what is affirmed by shari'a, or between two laws of shari'a, such as the correlation in the problem of ijza'.
- Practical reason: this type of reason cannot apprehend the laws of shari'a on its own; it can only apprehend whether a certain type of action has a certain value (such as rightness or wrongness) or not, without attributing it to the divine legislator (Shari'). When it apprehends this, it may, or may not, come to believe that there is a correlation between the law of reason and the law of shari'a. In this type of reason, the correlation holds only in cases of what the reason takes to be (morally) right or wrong.
Types of Rational Laws
The laws of reason, or rational laws, are of two types: independent and dependent:
- Rationally independent: this is a law of shari'a that is discovered by reason alone without drawing upon shari'a, such as the rational law of the rightness of justice.
- Rationally dependent: this is a law of shari'a discovered by reason with the aid of a certain law of shari'a, such as the rational law that prerequisites of an obligation are also obligatory. The obligation of the main action is a law of shari'a that implies, with the rational law about an action's prerequisites, the instrumental obligation of the preliminaries. Other examples of such laws include ijza', the opposites of an action that is subject to laws of shari'a, and the like.
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