Question
What are the evidences that prove that Abu Yusuf, Muhammad, Zufar, and Al-Hasan attained the degree of absolute ijtihad, especially since they fall under the same school of thought?
Answer
I say, and with God's help: Their principles are different from the principles of Abu Hanifa, and they can only belong to the absolute mujtahid. Muhammad linked his opinions and the opinions of Abu Yusuf with those of Abu Hanifa; if they were not absolute mujtahids, their opinions would not have been mentioned alongside the opinion of Abu Hanifa in the books of the apparent narration. The complete discussion is in the detailed introduction, and God knows best.