Di kalangan para Imam terdapat sebahagian yang mengemukakan beberapa prinsip yang diperselisihkan, lalu mereka berpegang kepadanya dalam sebahagian hukum mereka. Akibatnya, kedua-dua hukum dan prinsip itu menjadi punca perbezaan di kalangan para fuqaha. Sebagai contoh, majoriti fuqaha mengiktiraf kesahihan Ijma' di kalangan generasi selepas para Sahabat, tetapi Imam ash-Shaafi'ee mempersoalkan berlakunya Ijma' itu, manakala Imam Ahmad menolaknya sama sekali. Begitu juga, majoriti fuqaha menolak sikap Imam Maalik yang bergantung kepada adat kebiasaan penduduk Madinah sebagai sumber perundangan. Dan prinsip Istihsaan Imam Abu Haneefah serta Istislaah Maalik telah dilarang oleh Imam ash-Shaafi'ee kerana, pada pandangannya, kedua-duanya terlalu bebas daripada al-Qur'aan, as-Sunnah dan Ijma'. Dengan kata lain, pada pendapatnya, mereka terlalu banyak bergantung kepada akal manusia.

There were among the Imaams some who developed a number of controversial principles on which they based some of their rulings. As a result, both the rulings and the principles became source of differences among jurists. For example, the majority of jurists recognized the validity of Ijmaa’ among the generations after the Sahaabah, but Imaam ash-Shaafi’ee questioned its occurrence while Imaam Ahmad rejected it outright. Similarly the majority of jurists rejected Imaam Maalikreliance on the customs of the Madeenites as a source of legislation. And Imaam Abu Haneefah’s principle of Istihsaan and Maalik’s Istislaah were both disallowed by Imaam ash-Shaafi’ee as being too independent of the Qur’aan, the Sunnah, and Ijmaa’. That is to say, they relied too much, in his opinion, on human reasoning.

Di sisi lain, Imam asy-Syafi'i berpendapat bahawa pandangan para Sahabat wajib diterima dalam perkara hukum, manakala yang lain berpendapat bahawa ia hanyalah ijtihad mereka yang tidak mengikat generasi-generasi berikutnya.181

On the other hand, Imaam ash-Shaafi’ee felt that the opinion of the Sahaabah had to be accepted on legal matters, while others felt that it was only reasoning on their part which was not binding later generations.181