The first three books on the subject have not reached us viz. Abu Hanifah's Kitab al-Ra'y, and Abu Yusuf's and Muhammad ibn al-Hasan al-Shaybani's books bearing the title Kitab al-Usul. The earliest work which has reached us was written by al-Shafi'i, a student of al-Shaybani. Al-Shafi'i was linked with many traditions at the same time. He was horn in 150 AH, the year in which Abu Hanifah died. He did not, therefore, learn directly from Abu Hanifah, but he studied for many years under one of his distinguished pupils. Muhammad ibn al-Hasan al-Shaybani. Similarly, for many years he remained a student of Malik in Madinah. He studied philosophy, logic and dialectics. In those days the Mu'tazilah were at the height of their fame. He dabbled in debates with them as well. Many a quality combined in the person of al-Shafi'i with the result that he was able to render a signal service to Islam. One of them was his ability to serve as a link, connecting the groups of opposing trends among Muslims. 

Some of the Muslims then, as now, were conservative while others were progressive. People with these two opposing attitudes are found in every culture and community. Some people were busy collating and learning Hadith while some were interested in other subjects. Some jurists whose interest lay in law were busy contributing to the Islamic law with the help of logic and philosophy and their attention was somewhat diverted from Hadith.

JURISPRUDENCE AND IJTIHAD

The result was that in al-Shafi'i's day a serious rivalry had developed between the votaries of Hadith (ahl al-Hadith) and the votaries of reason (ahl al-ra'y). By 'votaries of Hadith are meant those who were busy collecting the sayings and commandments of the Prophet (peace be upon him), and by 'votaries of reason' are meant the jurists who were busy collating the laws of Islam which they sought to develop with the help of inference and analogy. Both were pulling in different directions because the votaries of reason were not well-acquainted with the Hadith. They presumed that the Hadith did not provide answers to all their questions. They resorted to reason and analogy and came out with new rulings. It sometimes happened that Hadith was found to contain answers to some of the problems posed by them. The votaries of Hadith would dub the votaries of reason as heretics, charging them with ignoring the Prophet's traditions although they certainly did nothing of the kind deliberately. The case simply was that they were unaware of the traditions concerned.

Shafi'i combined both the qualities in his person. He had acquired Hadith from the masters of the subject and he had learnt law from the masters of analogy. He also had a full command over philosophy and dialectics.

In his person, therefore, emerged a scholar who served as a link between the two schools and provided a synthesis. His greatest achievement was that he united the two conflicting schools. He was fully conversant with Hadith and was a leading expert in analogy, inference, deduction and ijtihad As a result he was able to satisfy both the schools.

Another achievement of Shafi'i is his authorship of Kitab al-Risalah which was aimed at creating unity of thought among Muslims. We can say that this is the oldest available book on Islamic jurisprudence. It has now been translated into many European languages. It has also been translated into Urdu. It can be said that by writing this book Shafi'i founded a new science. At least, he provided a strong foundation for it. The statements made in the book continue to hold the field even after the passage of centuries. The technical terms used by Shafi'i are still current coin.

The word risalah means "letter." The background to the use of this word as a title of the book is that he wrote it in deference to the request of a student who wanted a written lesson on the principles of jurisprudence. The answer was a long letter comprising a hundred and fifty pages. It deals in detail with such questions as: What is law? How is it made?  What are its sources? How can differences in those sources be resolved? How can a new law be made'? How to abrogate an old law? What is the way to interpret the relevant texts and the terms used therein? Shafi'i's Risalah attempts to answer these questions. It even explains the rules of language, prosody and rhetoric, illustrating it all with examples. Objections too have been answered by Shafi'i in a profoundly scholarly manner.

In the age of Shafi'i the Mu'tazilah were at the height of their influence and authority. They were disinclined to consider all traditions, in a simplistic manner, to be authentic. It is now generally believed that they rejected the Hadith as such. This, however, is a calumny. In reality their position was not that of rejection of Hadith. We have earlier mentioned a book of Abu al-Husayn al-Basri. It had been compiled by a Mu'tazilah scholar. He explains in detail the canons of the authenticity of traditions. A Sunni reader will find it difficult to differ with the principles formulated by him. How is it then, that the Mu'tazilah were condemned for their alleged rejection of Hadith? We should like to refer to the contribution Shafi'i made in this connection.

Scholars of the Mu'tazilah school believed that there should be more than one narrator of a tradition which lays down a law or from which a law could be inferred. A lone narrator could not be relied upon, not because he is wrong, but because law demands two witnesses to confirm a statement. This argument was rejected by other Muslim jurists. The traditonist scholars and Shafi'i gave a convincing reply, with the result that the objection of the Mu'tazilah to the reliability of single narrator traditions (ahad) lost their weight and people began to accept them. Shafi'i selected a number of instances from the life of the Prophet (peace be upon him) when action was taken on the evidence of one man. For example the Prophet (peace be upon him) dispatched a man one day, after the morning prayers, to go round and announce that the qiblah had been changed from Jerusalem to the Ka'bah. Only one person was sent. He asked the people during the prayers to turn their faces towards the Ka'bah instead of Jerusalem. The people acted upon his word. This proves that during the days of the Prophet (peace be upon him), action was taken on the evidence of one person,  and it was never held that unless two persons communicated the command of the Prophet (peace be upon him) it should not be obeyed. Shafi'i gave another example. One day in Madinah, a man appointed by the Prophet (peace be upon him) proceeded alone to proclaim the prohibition about alcohol. Anas, a well-known Companion, relates this incident which he witnessed during his childhood. This is a tradition recorded by al-Bukhari.

Anas states that at the time the messenger proclaiming prohibition passed by his house, he was serving wine to his guests. Immediately on hearing the proclamation, his father asked Anas to destroy the wine. He look up a hammer and broke the barrel into pieces. Those who were drinking threw their cups away. All this took place on the announcement of one person.

Shafi'i has given many examples to prove that one man's statement is enough to act on a tradition from the Prophet (peace be upon him). It was his great achievement that he was able to unite both the schools of tradition and the school of analogy so that they could serve better the cause of Islamic law. Until his time the traditionists tended to be concerned with the study of only the traditions and narrating them to others. They did not study other subject; like logic, philosophy, dialectics, etc. The result was that they insisted or, the application of the literal meaning of the words of the texts which was not appropriate. On the other hand, the votaries of reason insisted on resorting to analogy without fully searching, in the first instance, for relevant  references to the subject in the Hadith. Oblivious of the traditions, they would pronounce on legal questions on the basis of their personal opinion.
The credit goes to Shafi'i. Thanks to his impact, the traditionists began to follow a discipline in their subject and started writing Hadith under different chapters. 

Different traditions on the same subject were collected under one heading so that one could determine their chronology and decide which tradition had abrogated another. Followers of the school of reason also began to study Hadith. A new avenue for the development of Islamic law came into being largely due to the effort of Shafi'i.

So far only four books have been mentioned viz. Abu Hanifah's Kitab al-Ra'v. Kitab al-Usul by two students of his and Kitab al-Risalah by Shafi'i. Nothing new except commentaries have been published during the many centuries since the appearance of these books. Turks have made a major contribution in that they have written scores of books which are either repetitions of the old or their summaries or they sought to comment on them. A major work in two volumes by Abu al-Husayn al-Basri spread over a thousand and five hundred pages has been compressed into twenty pages by al-Baydawl. If has become a riddle. Then began a series of notes  and commentaries on al-Baydawi's book. The book of al-Baydawi was taught as a textbook and to explain it one needed the help of commentaries and notes which continued to be written.

THE MODERN TIMES

In modem times the most significant contribution to the subject has been made by the late Sir Abdur Rahim. He was once President of the Indian Legislative Assembly. Later he came over to Pakistan. At the invitation of the University of Calcutta, while he was a judge at the High Court of Madras, he gave a series of lectures which were subsequently published under the title Principles of Muhammadan Jurisprudence. He has made a little innovation in this field. He has dealt with the subject as discussed in the old books on the principles of jurisprudence and he has dilated upon the new books on philosophy and law published in recent times in Europe. He has tried to compare the two, i.e. the Islamic and the European principles of jurisprudence.
From this point of view Sir Abdur Rahim's Muhammadan  Jurisprudence opens a new chapter in our study of the classical books on the subject. For we come across a few factors which are not to be found in the old books. For example, the first question raised in the old books relates to the sources of law. The answer would be the Qur'an, the Hadith, consensus and personal reasoning. They would not deal with subjects or categories such as worship, worldly matters like criminal law and the law of inheritance, constitutional and commercial law, etc. Our classical books on jurisprudence do not take into account of these categories, Sir Abdur Rahim has treated legal subjects in the manner they are treated in modem legal works. It is his achievement that has combined the classical and modern learning in his comparative work.

THE PLACE OF IJTIHAD

In the end, we should like to briefly refer to ijtihad, an important principle of Islamic jurisprudence. The Prophet (peace be upon him) gave permission to Mu'adh ibn Jabal to invoke his own reason only in cases where the Qur'an and the Hadith were found silent on a certain issue. If the Qur'an is clear, the question of ijtihad does not arise. If the Qur'an is silent and the Hadith is clear, the question of ijtihad does not arise again. It can be resorted to only in case both the basic sources i.e. the Qur'an and the Hadith, are seen to be silent in respect of our question.

The effort at legislation in this event has been given a number of names by our jurists. Ijtihad is one; qiyas is another. Istidial (reasoning) is yet another, and so also is istislah. All these words are not synonymous. There are subtle differences of meaning between them. In this connection I would
like to mention the word istihsan in particular. It is associated with the Hanafi school so closely that other schools of jurisprudence do not like it. You should not be surprised, therefore, that Shafi'i has written a tract in refutation of istihsan. The book is entitled al-Radd 'ala al-Istihsan. It seems from its study that a certain presumed meaning has been given to the word istihsan which the author proceeds to reject.
According to the Hanafi school of law, istihsan would mean that it is not enough to study the obvious circumstances of a case, but one should go deeper into the matter before giving a ruling on the issue in question. 

We shall cite an example. Suppose we entrust a person with something and ask him to convey it to a particular person. One would ordinarily expect that he would deliver the same thing to its destination. A money order is sent these days through the post offices. We entrust a sum of money to the post office with the request that it should be delivered to a certain person. The common principle of trust demands that the person concerned should convey the same money to the given address. But according to the postal system, the money handed over to it is deposited in the treasury and the man who receives the money order is provided with an equal sum. It is not necessary to dispatch the very same money that the sender of the money order has paid. This is exactly the meaning of istihsan. Even though the current system of delivering the entrusted money is different in a superficial sense from the concept of trust, yet it facilitates the discharge of the trust, without changing the value of the money for the sum to be delivered equal to the sum paid by the sender. Hence the substance of the concept of trust has not been violated.

This applies not only to individual opinion or an Inference but also covers collective opinion. At least the Hanafi school of law accepts that a new consensus can cancel an old consensus. Suppose there is a consensus on a certain issue. We accept its authority but it does not mean that no one can oppose it till eternity. If someone has the courage to oppose it with due respect and reason, and if he can persuade the jurists to accept his point of view, a new consensus comes into being. The new consensus abrogates the old one. This principle has been propounded by the famous Hanafi jurist, Abu al-Yusr al-Bazdawi in his book Usal al-Fiqh (Principles of Jurisprudence). AI-Bazdawl belongs to the fourth and fifth centuries of the Hijrah. This work is a great contribution to Islamic jurisprudence. It is on account of his statement that we can say that consensus cannot become a source of difficulty for us. If a consensus is reached on some issue and it is found subsequently to be unsuitable, the possibility remains that we may change it through reasoning and create a new one cancelling the old consensus.

The purpose of this brief comment was to underline the fact that Muslim's have codified their law after the demise of the Prophet (peace be upon him) in a manner which has not only preserved it for posterity but has also ensured that it remains practicable through the ages. It is a universally recognised principle that a law Ian be changed either by the Law-maker Himself or an authority higher than His. Anyone of a lower status cannot change the law. If God has given a command, He alone can change it. If a Prophet (peace be upon him) has pronounced a verdict, he or another Prophet can change it and indeed Allah can, but no authority lower than that of a Prophet (e.g. a jurist) can change the taw laid down by a Prophet. The opinion of a jurist can, however, be rejected by another jurist who can offer his own opinion instead.