Many people wonder why it is that the mujtahids differ at times in their fatwas, when the basis of their Ijtihad are the same. It should be observed that difference in scientific opinions is not to be taken as a sign of a substantial defect in the quest for knowledge. It is rather, a sign that knowledge moves in progressive steps towards perfection. Differences of opinions are to be found in all sciences, not just in fiqh.
There may, for example, be more that one opinion about the therapy for a particular patient's ailment, and all of these opinions may be superseded later on by the development of new methods of dealing with that malady. Thus, this difference can be seen in the light of difference between scientists and should be regarded as stages to be passed in its route to perfection.

It should be remembered that the mujtahid formulates his opinions after pushing his research and study as far as he can; that is all that is expected of him, for he is neither infallible nor the knower of the unseen.

The most important and dangerous question which remains unanswered is that why do the mujtahids differ among themselves in their religious opinions concerning an issue while there is one Shari'ah and its laws are one? Or why do the mujtahids' religious opinions differ concerning one subject?

To answer the question, we should differentiate between the two cases: the case in which the differences are founded on sound bases and lawful practice.

The second case is that the differences are made out of extemporaneous Ijtihad which is not founded on a sound base nor is scientific according to the spirit of Shari'ah and its sources.

The first difference is a natural result of a sound scientific reasoning and the mujtahids are excused for any short comings nor could they be punished on the day of Resurrection because their intention was sincere. It is the second case or difference which is neither Ijtihad nor Fiqh but it is a haphazard act against the spirit of Shari'ah and its principles, and the person responsible and his blind followers will be held responsible on the day of Resurrection.

The science of jurisprudence - as we explained - is similar to other sciences and human knowledges. As each of these sciences has its own rules, principles, the Islamic Shari'ah has its own principles and laws too.

As the physicist, in the previous example, tries to spend all his scientific efforts to discover laws related to physics within the framework of its nature, existence; or the logician who devotes all his efforts to discover the laws of thinking according to its intellectual basis, and it is not for them to coin laws of their own on mere fancy; so does a mujtahid (faqih), who has no ability or right to make laws and principles in a haphazard manner, and then try to legitimatize them. If anyone has dared to do this, then his laws should scientifically analyzed on the basis of the Qur'an and the sunnah.

The same idea is applied to a physicist and logician who sometimes makes a mistake in discovering scientific laws and rules and that this wrong discovery does not represent the true law of physics and logics but it represents the understanding of a scientist who made a mistake in identifying the law. The case is the same concerning the faqih who may sometimes make a mistake while practising the act of deriving Islamic laws from their original sources - the Book and the sunnah - but his mistake is not done blindly and at random but due to his insufficiency or inadequacy in his scientific tools or his self capacity which causes him to be unable in deriving legal law as it is formulated in the world of law and a divine Shari'ah.

This is the reason why the faqih is excused when he makes a mistake in arriving at the right law.

The main differences, whether being among the mujtahids of various Islamic schools of jurisprudence such as Hanafi, Shafi'i, Shi'ah, Maliki...etc. or among the mujtahids of one school, belong to the following reasons:

1- Linguistic difference concerning some texts of the Holy Qur'an and Prophetic traditions due to the difference in grammar, meaning or in reading which leads to the difference in understanding and formulating laws. For example, their difference in the following verse of ablution when the Almighty Allah says:

"O you who believe, when you rise up for prayer, wash your f aces, and your hands up to the elbows, and wipe your heads, and your feet up to the ankles. And if you are under an obligation, then wash (yourselves)..."

Holy Qur'an (5:6)

Whoever among the scholars considers the word 'feet' grammatically is joined to 'faces', makes its washing obligatory and whoever considers the word 'feet' as joined to 'heads' makes its wiping obligatory.

Or their difference in the meaning of 'quru" in the Almighty's saying:

"And the divorced women should keep themselves in waiting f or three monthly courses (quru');..."

Holy Qur'an (2:228)

Scholars (faqihs) differ among themselves concerning the linguistic meaning of the word 'quru"; some consider it as the period of cleanness (tuhur) while others explain it as period of menstruation (haydh). Each of these two opinions depend on their own linguistic interpretation or understanding because the word 'quru" in Arabic language is called for both the period of cleanness (tuhur) and the period of menstruation (haydh).

In accordance with this linguistic difference, scholars differ among themselves in waiting period of a divorced woman; is it three periods of cleanness - after divorce - or is it three complete months because what is meant by 'quru" is the period of menstruation (haydh) because the word haydh is a symbolic name for woman's monthly period by considering it as a monthly period which occurs once every month.

Another example, is (heir difference in reading the Almighty's saying 'hata yatharna' (until they have become clean) in the following verse:

"And they ask you about menstruation. Say it is a discomfort; therefore, keep aloof from the women during the menstruation and do not go near them until they have become clean; then when they have cleansed themselves, go in them as Allah has commanded you; Surely Allah loves those who turn much (to Him), and He loves those who purify themselves."

Holy Qur'an (2:222)

Whoever reads the word 'they have become clean' as stressed, does not allow to make sexual intercourse with women during the period of menstruation until they have become clean (i.e. to take the ritual bath) but whoever reads it without stress allows to make sexual intercourse with her whenever cleanness is achieved (i.e. the stopping of blood).

Or their difference concerning whether the command denotes (signifies) obligation or permission; whether a prohibition indicates prohibition or reprehensibility; whether the word denotes reality or figurative or their difference among the texts like generalization, restriction, universality or specification...etc.

2. The difference concerning the meaning of a text (of the Book (Qur'an) and the Prophet's sunnah). Indeed scholars may differ in their understanding the signification of a text and its meaning like their difference in the following saying of Allah, the Most High:

"Divorce may be (pronounced) twice; then keep (them) in good fellowship or let (them) go with kindness..."

Holy Qur'an (2:229)

"So if he divorces her (the third time), she shall not be lawful to him afterwards until she marries another husband. If he divorces her, there is no blame on them both if they return to each other (by marriage),..."

Holy Qur'an (2:230)

Surely the reason of difference in understanding Allah's saying (divorce is twice) is the appearance of jurisprudential laws based on personal opinions, with some ruling prohibition of a wife to her husband if he divorces her three times by simply saying that 'you are divorced'; depending on his understanding of the above mentioned verse (divorce is twice). At the third time, after passing a greater separation, he has no right to marry her until she marries another husband and if the new husband divorces her, then only the first husband has the right to marry her after completion of her monthly waiting period.

But another group explains the Almighty's saying (divorce is twice) that divorce should be achieved practically but not simply orally in order that a wife becomes forbidden to her husband. The Holy Qur'an does not mean merely the repetition of word (verbal) but it means the real occurrence of the permitted divorce in which the wife returns to her husband's house twice. As a result, if a third divorce occurs, she becomes haram (forbidden) for him to remarry. For more explanation, if the husband divorces his wife, he has the right to marry her again; if she returns and he divorces her the second time, he also has the right to take her back but if she returns and he divorces her for the third time, she becomes haram for him to remarry unless all the following conditions are fulfilled:

a. She permanently remarries another man.
b. The wife and her second husband have sexual intercourse.
c. The second husband either divorces her or dies.
d. She completes her waiting period (iddah) for the second husband.

3. The difference whether some laws are repealed or not, for example their difference regarding the law of temporary marriage (mut'ah).

4. The difference caused by accepting or rejecting certain narrations or traditions. Scholars after a thorough scientific analysis of chain of transmitters, accept or reject a tradition.
Traditions which contradict the Qur'anic concept or a proved Prophetic tradition, are normally discarded as spurious. If the sources or the chain of transmitters are sound and the wordings in conformity with the Qur'an and the sunnah, then the tradition is as accepted as satisfactory.

5. The difference in considering the validity and invalidity of some of these sources and how to make use of them, such as: analogy, approbation, intellectual proofs, and consensus of opinions.

Some scholars depend on some of these sources in formulating laws while others refuse to do so pointing out the drawbacks of these sources.

Thus, this is the main reason behind the difference among the scholars of Islamic schools and the followers of opinion. Therefore, it is necessary to submit all disputed independent reasoning opinions among the Muslims to a thorough scientific criticism in order to remove the clouds of personal fanaticism and bigotry, and arrive at the ultimate truth keeping in the mind the aims of Islamic Shari'ah in reforming and uniting the Muslim communities.