Many of the ‘Ulamaa’ adopted Al-Istihsaan and considered it to be a Daleel from amongst the Adillah of the Ahkaam whilst they have disagreed in respect to its definition.

Some of them like the Hanafiyah considered it to represent an outweighing of a Daleel over a Daleel and therefore it represents a Hukm that is established by the text and no Istihsaan.

For that reason, we see Abu Ishaq Ash-Sheeraaziy Ash-Shaafi’iy, after presenting some of the views of the Fuqahaa of the Ahnaaf in respect to the meaning of Al-Istihsaan, saying: “If it means specifying some of the sum of the whole with a Daleel that specifies it or by judging by the strongest of two evidences, then this is from that which nobody can reject” (Al-Lam’u p68).

And we see that As-Sam’aaniy and Al-Qaffaal said the meaning of:

“The explanation of Al-Istihsaan as being a departure from a Daleel to a Daleel that is stronger than it, is something that we say and do not reject” (Irshaad Al-Fuhool of Ash-Shawkaani, p241).

Those who upheld Al-Istihsaan included: The Hanafiyah, Al Imaam Maalik and his followers whilst Ibn ul-Haajib said in his ‘Mukhtasir’:

The Hanafiyah and Al-Hanaabilah upheld it whilst the others rejected it.

The Shaafi’iyah, at the head of which was Imaam Ash-Shaafi’iy himself, the Zhaahiriyah and many of the Mutakallimeen held the opinion of the absence of the Hujjiyah (evidential validity) of Istihsaan and the impermissibility of building legal rulings upon it.

The following statement of Ash-Shaafi’iy became well-known:

“Whoever utilises Istihsaan then he has legislated” in addition to his statement: “Al-Istihsaan is self-gratification and an opinion based on desire” (Al-Aamaadiy Vol.4 p209).

In his book ‘Al-Umm’ he dedicated a chapter in the seventh volume under the title of: ‘Invalidating Istihsaan’. The following, in summary, are the Adillah that he used to invalidate it:

1 - The Sharee’ah is a Nass (text) and taking an understanding from the text by way of Qiyaas. If Istihsaan is one of these two (categories)

then there is no need to mention it and if it is outside of these two (categories) then it is not from the Sharee’ah.

2 - Verily Allah Ta’Aalaa says:

And Al-Istihsaan is neither the Kitaab nor the Sunnah and it does not represent referring back to the Kitaab and the Sunnah.

3 - The Messenger of Allah (saw) did not provide verdicts based on his Istihsaan but rather he would await the descent of the Wahi to respond to the queries and questions of his companions like what happened in respect to the reality of Azh-Zhihaar (Soorah AlMujaadalah) and of Al-Li’aan (Soorah An-Noor 6-10).

4 - The Messenger of Allah (saw) rebuked the Sahaabah who adopted based upon their Istihsaan. So for example he (saw) rebuked some of the Sahaabah because they had burnt a Mushrik sheltered by a tree and he (saw) rebuked Usaamah Bin Zaid because he killed a man who said: ‘Laa Ilaaha Illallah’ whilst using the argument that he only pronounced it due to fear and under the threat of the sword.

5 - Al-Istihsaan without evidence has nothing governing it and no measure to be used to evaluate the truth from the falsehood. As such, within one single matter, there would be a variety of Ahkaam without a base to outweigh one over the other.

6 - If Al-Istihsaan was permissible for a Mujtahid and in its use he did not depend upon a Daleel Shar’iy, then it would also be permitted for someone who does not have knowledge of the Kitaab and the Sunnah. The result of that is that the opinion would be based on desire and not ‘Ilm (knowledge).

These evidences that Ash-Shaafi’iy brought to invalidate Istihsaan apply to invalidating the Istihsaan as utilised or held by the Maalikiyah who consider Istihsaan to be Al-Maslahah Al-Mursilah in accordance to the speech of Al-Imaam Maalik: “Al-Istihsaan represents nine tenths of knowledge (‘Ilm)” whilst he included AlMaslahah Al-Mursilah within the generalness of Istihsaan.

As for Al-Istihsaan in the view of the Hanafiyah, then the evidences provided by Ash-Shaafi’iy to invalidate Istihsaan apply upon a part of its usage, which is the Istihsaan Al-‘Urf, whilst it does not apply to another part of its usage, which is the Istihsaan that is reliant upon the text and reliant upon Ijmaa’. This is the Istihsaan As-Sunnah and Istihsaan Al-Ijmaa’.