Islamic inheritance jurisprudence

The Qur'an introduced a number of different rights and restrictions on matters of inheritance, including what were at that time general improvements to the treatment of women and family life.[1] The Qur'an also presented efforts to fix the laws of inheritance, and thus forming a complete legal system. This development was in contrast to pre-Islamic societies where rules of inheritance varied considerably.[1] They do, however, also differ from ongoing secular egalitarian improvements since that time, up to, though principally in, the modern era.

Furthermore, the Qur'an introduced additional heirs that were not entitled inheritance in pre-Islamic times, mentioning nine relatives specifically of which six were female and three were male. The laws of inheritance in the Qur'an also included other male relatives, such as the husband and half-brothers from the mother's side, who were excluded from inheritance in old customs. The heirs mentioned in the Qur'an are the mother, father, husband, wife, daughter, brother who shares the same mother, full sister, sister who shares the same mother, and consanguine sister.[2]

In general, the Qur'an improved the status of women by identifying their share of inheritance in clear terms. It also completely forbade the practice of inheriting widows.^[4:19] Orientalist Joseph Schacht states that "this is not meant as a regular legal ordinance, but is part of the Qur'anic endeavor to improve the position of women."[1] The Qur'an does not explicitly mention the shares of male relatives, such as the decedent's son, but provides the rule that the son's share must be twice that of the daughter's. Muslim theologians explain this aspect of inheritance by looking at Islamic law in its entirety, which bestows the responsibility and accountability on men to provide safety, protection and sustenance to women.^{[Qur'an 4:34]}[2] One explanation of why a daughter is entitled to only half that of the son is that Islam decrees that women, upon marriage are entitled to a "dowry" from the husband (in addition to any provision by her parents). It is thereafter the husband's obligation to care for and maintain his wife and the "dowry" is, therefore, essentially an advance of inheritance rights from her husband's estate.

In addition to the above changes, the Qur'an grants testamentary powers to Muslims in disposing their property.^{[Qur'an, 2:180–182, 2:240, 4:33, 5:106–107]} In their will, called waṣeyya, Muslims are allowed to give out a maximum of one third of their property. Muslims are also encouraged to give money to the orphans and poor if they are present during the division of property.

The Qur'an contains only three verses ^{[4:11, 4:12 and 4:176]} which give specific details of inheritance and shares, in addition to few verses dealing with testamentary power. It has also been reported in Hadith that Muhammad allotted great importance to the laws of inheritance and ordered his followers to learn and teach them.[1] Muslim jurists used these verses as a starting point to expound the laws of inheritance even further using Hadith, as well as methods of juristic reasoning, like Qiyas. In later periods, large volumes of work have been written on the subject.[2]

This amalgamation of old agnatic customs and Islamic law led to a number of problems and controversies that Muslim jurists have solved in different ways.[2] Through the use of deductive reasoning (Qiyas), Muslim jurists added three additional heirs: the paternal grandfather, maternal grandmother, and agnatic granddaughter. These heirs, if entitled to inherit, are given their fixed shares and the remaining estate is inherited by the residuaries (ʿaṣaba).[2] This led to some minor differences between jurisprudence schools of the Sunni maddhabs. Also, the laws of inheritance for Twelver Shia, despite being based on the same principles, differ in a number of features due to the rejection of certain accounts of Hadith and based on their understanding of certain events in early Islam.[1] On the other hand, the system of inheritance of the Kharajite Ibadis and Zaidis closely resemble that of the Sunni system.[1] In modern Muslim countries, usually a mixture of different schools of jurisprudence (including Shia) is in effect, in addition to a number of important reforms to the traditional system. The main achievements of such modern systems was the codification of inheritance laws.[1]

Inheritance is considered as an integral part of Shariah Law. Muslims inherit from one another as stated in the Qur'an.^{[Qur'an 4:7]} Hence, there is a legal share for relatives of the decedent in his estate and property. The major rules of inheritance are detailed in Qur'an, Hadith and Fiqh.

When a Muslim dies there are four duties which need to be performed. They are:

1. Pay funeral and burial expenses.
2. Paying debts of the deceased.
3. Determine the value / will of the deceased if any (which is capped to one third of the estate as the remainder is decided by shariah law).
4. Distribute the remainder of estate and property to the relatives of the deceased according to Shariah Law.

Therefore, it is necessary to determine the relatives of the deceased who are entitled to inherit, and their shares.[2]

These laws take greater prominence in Islam because of the restriction placed on the testator (a person who makes a will). Islamic law places two restrictions on the testator:

1. To whom he or she can bequeath his or her wealth.
2. The amount that he or she can bequeath (which must not exceed one third of the deceased's estate).[2]

The Islamic law of inheritance served as an impetus behind the development of algebra (derived from the Arabic al-jabr) by Muhammad ibn Mūsā al-Khwārizmī and other medieval Islamic mathematicians. Al-Khwārizmī's Hisab al-jabr w’al-muqabala, the foundational text of algebra, devoted its third and longest chapter to solving problems related to Islamic inheritance using algebra. He formulated the rules of inheritance as linear equations, hence his knowledge of quadratic equations was not required.[16]

Al-Hassār, a mathematician from the Maghreb (North Africa) specializing in Islamic inheritance jurisprudence during the 12th century, developed the modern symbolic mathematical notation for fractions, where the numerator and denominator are separated by a horizontal bar. The "dust ciphers he used are also nearly identical to the digits used in the current Western Arabic numerals. These same digits and fractional notation appear soon after in the work of Fibonacci in the 13th century.[17][18][19]

In the 15th century, Abū al-Hasan ibn Alī al-Qalasādī, a specialist in Islamic inheritance jurisprudence, used characters from the Arabic alphabet as a mathematical notation system in algebraic equations.[20]

• Women and Islam
• Mathematics in medieval Islam

• Division of Inheritance According to Qur'an
• Inheritance in Islam