There has been a tendency amongst some Muslims writers to argue that Islamic Law has nothing to do with human intellect. Their reasons for such claims are based basically on misunderstanding about the message of the Qur’an. 
    An important argument presented to prove the Islamic shari‘ah's lack of concern for human intellect is based on the verses which emphasise that the believers should listen to the Prophet (sws) and obey. It is argued that since there is no mention of understanding in the contents of the Message in these verses, intellectual reasoning is not a part of an ideal Muslim's behaviour. On careful examination, however, the argument fails to convince. The verses referred to in the argument are emphasising action not at the expense of intellectual reasoning but, instead, at the expense of unacceptable human desires. Such verses, therefore, mean that ideal Muslim behaviour is to obey Allah and the messenger whether the demand made by them conforms to the desires of the individual or not. The distinction is drawn with the baser human desires and not with human intellect. 
    Another reason why the opinion alleging the Islamic shari‘ah's lack of conformity with human intellect became popular was the fact that some Muslims could not find intellectually acceptable answers to the questions raised about some aspects of the Shari‘ah. The most effective way of silencing such threatening  queries was to remind the questioner that Islam had nothing to do with human intellect. In actual fact many such questions could not be answered either because those questioned were unable to find reasonable answers or because the questions were raised about those verdicts which were not a part of the Islamic Law, but were the juristic opinions of some scholars. 
    In reality the Qur’an attaches great significance to human intellect. It appeals to the intellect of its addressees to convince them about its authenticity as the Word of God. It condemns those who fail to use their intellects as unworthy of God's blessings, and worse than beasts. Moreover, those without sound mental ability -- like children before reaching the age of puberty and the insane -- are not expected to follow the contents of the message of Islam according to the Prophet (sws). 
    The original sources of knowledge on Islam, far from taking the role of opponents of human intellect, are bound with it in a relationship more akin to that of a guide to one who is being guided. The Qur’an acknowledges human intellect as basically a blessing from God Almighty and considers the verdicts of sound intellect as the very verdicts of God. In verse 222 of chapter 2 of the Qur’an, for instance, God Almighty has asked believing men to approach their wives ‘as Allah has commanded you’. The ‘command’ of God mentioned in this verse is not referring to any formal legal injunction from God, but to an instinctive urge in man on the basis of which his intellect regards a certain way as deviant behaviour. We can conclude from this argument that all the unequivocal verdicts which human intellect gives on the basis of the stimuli it receives from instincts and intuituion are also the directives of nature and as such are part of Divine guidance. 
    However, this fact about intellect does not mean that human intellect does not have its limitations. It can be persuaded to accept, for example, what contradicts its own instincts because of its greed or timidity in a given situation. Unrestricted enthusiasm for a certain ideal, likewise, can cause the intellect to be biased for what is unworthy of its approval. There are moreover some intriguing problems which are beyond the reach of its grasp. All these limitations constrain the effectiveness of human intellect if used without restrictions. It seems to yearn -- given these restrictions -- for external guidance. Divine Revelation in the form of messages of the prophets (sws) is that very guidance. The Qur’an and Sunnah constitute the final version of that guidance. The Qur’an has described this relationship between Divine Revelation and human intellect as light upon light (Qur’an 24:35), that is, the guidance of human intellect is basically a light, although with flaws (and therefore dim), whereas the Divine Revelation in the form of the Qur’an is a brighter light to make up for the flaws of the intellect. Thus a brighter light (the Divine Revelation) shows the way to a dimmer one (human intellect). 

Systems in Islamic Law
    If an economic system is defined as ‘the sum total of institutions and patterns of behaviour that organise economic activity in society’, then no such system can be claimed to be found in the original sources of Islamic law. Islam has not specified detailed procedures. In fact, the Shari‘ah has laid down only the essential elements of a basic strategy and detailed policy measures have been left to be evolved by the collectivity in the light of its peculiar circumstances. It would have been highly unworkable for a message to outline minute details of the working of a system to be followed for all times to come. Because of the evolutionary nature of human societies, any such effort would have been met with stiff resistance from forces of change soon after its introduction. Thus, it has been rightly observed that the original sources of Islamic law did not ‘expressly provide solutions for all the legal problems inherent in the organisation of a society’. 
    Instead of giving details of systems in various aspects of human activities, the Islamic Shari‘ah confines itself to providing basic principles in the form of laws. ‘It is typical feature of Islamic teachings that strictly mandatory elements are kept to a minimum while a wide area of discretion is allowed to man to organise and order his affairs’. It is therefore surprising that some authors insist on using the expression ‘system’ to describe Islam's guidance on various aspects of human collectivity. In fact, there can be different systems in different times and places, each rightfully claiming to be called Islamic if found not to be in conflict with the teachings of Islam. 

Spirit of the Islamic Law
    The Divine Law of Islam is based on the Qur’an and Sunnah. The legal injunctions on various issues contained in these sources are meant to achieve certain objectives which are the real spirit of the law. These objectives are in some cases clearly set forth, while in others these are implied. Muslims are expected to follow the law both in letter and in spirit. A situation whereby they are following the letter of the Islamic law in disregard to its spirit cannot be regarded as desirable at all. 
    The Qur’an, for instance, has directed its followers to perform formal prayers (Salah) on many occasions. It has also clarified that one of the purposes of performing Salah is to remember Allah. If a Muslim community strictly observes all the rituals of salat, but ignores its real purpose, it will be guilty of ignoring its spirit despite going through the formal motions. The same observation holds true for all injunctions in the Qur’an and Sunnah. Another example is regarding the prohibition of interest (Riba). It is clear from the Qur’an that all interest-ridden transactions have been forbidden and that trading based on the basis of profit and loss sharing is permitted because, while the former is unfair, the latter is, in principle, fair. If on the basis of the Qur’anic permission, some Muslim traders start exploiting the financially weak by entering into profit and loss agreements with them which are grossly unfavourable to the latter, the arrangement would still be considered Islamically unacceptable, despite its apparent legitimacy. 

The Spirit of Law and Hiyal
    The Qur’an criticises the behaviour of some of the people of the Book and says that the arrival of Jesus, may Allah be pleased with him, was meant, in the Divine Scheme, to instil the real spirit of the law among the Jews who had reduced Torah to a ‘collection of life-less injunctions and spirit-less rituals’. 
    The Qur’an mentions the behaviour of a Jewish community who lived by the seaside. They were required to honour the restrictions of Sabbath by not getting involved in any worldly engagements. It so used to happen that while ‘on the day of their Sabbath their fish did come to them, openly holding up their heads, but on the day they had no Sabbath, they come not’. It was too tempting a trial for some of them. However, in order to preserve the apparent sanctity of Sabbath and yet achieve their objective, some of them contrived a clever strategy of preventing the fish from disappearing on Saturday, so that on Sunday, the day following the Sabbath day, they could catch them. Despite their lame attempt to preserve the apparent form of the law of Sabbath, however, they were condemned to punishment because the spirit of the law -- to stay away from all worldly dealings on Saturdays in order to worship God -- was totally lost. 
    Another reference in the Qur’an to a religious subterfuge contrived by a people to serve their worldly objectives is the practice of intercalating a month  by the pagan Arabs. They were required by their religious traditions to honour the sanctity of four months by enforcing complete seizure to active hostilities against each other. The requirement was meant to enable pilgrims to visit the House of Allah in Mecca from all over Arabia. However, since the calendar was based on the lunar calculation, it necessitated the shifting of months from one season to another. That was not acceptable to the business-minded people of Mecca because pilgrims were an important source of business revenue for them. They inserted a thirteenth month after every three years to ensure that the months did not move around different seasons in different years. In short, instead of openly rejecting the arrangement of lunar months, they resorted to clever manipulations by retaining the apparent form of the law. The Qur’an has, however, condemned the whole exercise by calling it ‘an addition to unbelief’ (Qur’an, 9:37). 
    The reason why religious subterfuges have been condemned by the Qur’an as additions to unbelief is that while simple unbelief is an open rejection of faith, such subterfuges are a cunning way of defeating the purpose of the Divine Law without taking the blame for rejecting it. In other words, those who indulge in it attempt to deceive God by pretending to follow the apparent form while defeating the real spirit. 
    There have been examples in Muslim history too whereby religious subterfuges have been resorted to retain the legal form of injunctions while defeating the real spirit. It is said, for instance, about a certain individual well versed in religious law that he used to transfer his wealth to his wife's name after eleven months and similarly back to his name after the same duration to escape the obligation of paying the annual religious tax (Zakah) on his wealth. Indeed Zakah is, legally speaking, payable on the wealth one owns over a period of one year. That, however, is just a legal condition. The real objective Allah Almighty wants to achieve through its imposition is amelioration of the state of the poor and material sacrifice for the sake of Allah by the payer. The individual referred to managed to defeat both objectives, although in the eyes of the worldly law he, perhaps, was not guilty. Bukhari has given his opinion on this type of practice by stating that, though such individuals may have escaped the legal imposition of Zakah, yet they have disobeyed the Prophet of Allah (sws). 

Conclusion
    Any attempt to implement the Shari‘ah in modern Muslim society should take place within the bounds of the two original sources of knowledge of Islam: the Qur’an and Sunnah. The guidance within these sources is basic. It is up to the Muslims of each generation to devise systems relevant to their conditions which should be based on those basic teachings. That process should be undertaken with the help of reliable and competent religious scholars. It should be made certain that the system thus devised adheres not just to the apparent form of Islamic teachings, but to the true spirit of the Islamic law as well. The latter requirement necessitates that no religious subterfuge should be allowed in the name of the Islamic Shari‘ah.