Legal Opinions

According to the Sunnis, the following four elements are valid sources to derive Islamic laws

• The Quran
• The Hadith (saying of the Prophet)
• Scholarly Consensus (Ijma)
• Reasoning by Analogy (qiyas)

According to the Mutazilah, the legal opinions must only be based on

• The Quran
• The Hadith
• Human Reasoning (Aql)

Contention between the two groups can be summarized in the following philosophical question which predate Islam itself

The Hanbali traditionalists (as well as the Ash'ariya and other groups within the orthodox center) differed sharply with the Mu'tazila on whether the Law (Shari'a) that God revealed through His prophet Muhammad was good because God had revealed it, or whether God had revealed it because it was inherently good. [1]

On page 17, the authors quoted an interesting saying about the need to define your religion and to contrast it with others.

there is an obvious need for a religious group to define itself in relation to other groups, and to the world in general.[1]

The most celebrated time for the Mutazilah was under the Abbasid caliph al-Ma'mun (year 813-833 AD). After losing the support from the caliph, the Mutazilah madhhab began to decline. This gave rise to other Sunnite madhabs like the Ash'ari and Maturidi.

After the demise of Mutazilah scholar Abd al-Jabbar (d. 1024), the next scholar among this sect was the famous Quranic scholar, al-Zamakhshari (d. 1144).

Among the Sunni theologians, the majority of whom identified with the Ash'ari madhhab after the eleventh century, Mu'tazili doctrine was the target of attack and derision; Mu'tazili masters were often condemned from pulpits during the Friday prayer service.[1]

it was the Zaydi (Fiver) and Imami (Twelver) Shi'a more often than the Sunnis who continued to discuss the early Mu'tazili writings [1].

end at page 18

Reference
[1] Martin, Richard C, Woodward, Mark R and Atmaja, Dwi S. 1997. Defenders of Reason In Islam: Mu'tazilism and Rational Theology from Medieval School to Modern Symbol. Oneworld Oxford. Preface. ISBN 978-1851681471