What are the types of islamic jurisprudence? What are the four sources of islamic jurisprudence?
In addition to the imams of the four schools of Islamic law and their students, who were formed during the second and third centuries of the Hijra, many other great and independent mujtahids also lived during the same period, and there were partial groups formed around their names. The main ones are:
Sufyan Ibn Uyayna (d. 198/813) in Mecca; Sufyan al-Thawri (161/778), Ibn Abi Layla (d. 148/765), Ibn Shubruma (d. 144/761) in Kufa; Abu Thawr (d. 240/854), Dawud al-Zahiri (d. 270/883), Ibn Jarīr al-Ṭabarī (d. 310/922) in Baghdad; Lays ibn Ṣaʿd (d. 175/791) in Egypt; Hasan al-Basri (d.110/728) in Basra; al-Awzai in Damascus (d.157/774); Ishaq Ibn Rahuya (d. 238/853) in Nishapur. These mujtahids developed their own ijtihād methods and issued many fatwas, but they could not emerge as a school because they did not have any followers. However, their views are an important wealth of fiqh for Islamic legal doctrine and in terms of its codification.
Today, the Zahiriya school is known for its harsh criticism and different perspectives against the opinion (ra’y) and the ijtihād movement. It is also worth mentioning separately its two representatives, i.e. Dawud al-Zahiri (d. 270/883) and Ibn Hazm (d. 456/1064). Even though this school, which opposes ijtihād based on analogy and personal opinion, and argues that the literal (zāhir) meaning of verses and hadiths should be taken as a basis, was effective for a while after the fourth century of the Hijri, but later it dissolved into the Shafiʿi school, which is close to it at some points.
The legal studies of the Shia schools are at the forefront of the other schools of Islamic law that are not included in the Sunni schools. The three major branches of Shia can also be seen as a school of Islamic law. Imamiyya is also known as Ja’fariyya because it is based on the views of Ja’far al-Sadiq in creed and fiqh. In Ja’fari fiqh, there is a classification similar to the classification between people of hadith and people of ra’y in Sunni fiqh. Their representatives are called “akhbaris” and “usulis”. Akhbaris take the hadiths as a basis for making judgments and say that the Qur’an can only be understood with the help of these hadiths. The Usulis, on the other hand, base their legal views on four proofs: The Book, the Sunnah, the consensus, and reason. However, Shia’s understanding of Sunnah and ijmāʿ is different from that of the Ahl al-Sunnah. Ja’faris take the words, actions, and approvals of the Prophet and the innocent imams (twelve imams) as their criteria and accept only the hadiths narrated by the Ahl al-Bayt (family of the Prophet Muhammad). They have different views and practices, for example, they allow the mut’a marriage, they see wiping of bare feet in ablution as sufficient, two witnesses in a divorce are required, they perform the ritual daily prayers only thrice, and the collecting of zakāt (khums) is carried out by the clergy.
Zaydiyya, the other branch of Shia, is close to the Ḥanafi school in terms of legal views. There are different opinions on some details such as the prohibition of eating the meat of an animal slaughtered by a non-Muslim and marrying a woman from the People of the Book. Since the legal views of the other branches of the Shia, which is basically the political and theological school, or the sects such as the Kharijites, on certain issues are also present in the Ahl al-Sunnah, they do not constitute a significant difference.
 For more information see Bekir Topaloğlu, Kelam İlmi, Istanbul 1981, p. 218 ff.; Mustafa Öz, “Ca’fer es- Sadık”, TDV İslam Ansik., “Şia”, Şamil İslam Ansik.; Hamdi Döndüren, “Ca’fer-i Sadık”, Şamil İslam Ansik.; Komisyon, İlmihal, I, 39-40.
Source: Basic Islamic Principles (ʿilmi ḥāl) According to the Four Sunni Schools With Evidence From The Sources of Islamic Law, Prof. Hamdi Döndüren, Erkam Publications