Qiyas (Analogical Deduction)

49. Literally, qiyas means measuring or ascertaining the length, weight, or quality of something, which is why scales are called miqyas. Thus the Arabic expression,qasat al-thawb bi'l-dhira` means that 'the cloth was measured by the yardstick'. qiyas also means comparison, with a view to suggesting equality or similarity between two things. Thus the expression "Zayd yuqas ila Khalid fi `aqlihi wa nasabih" means that 'Zayd compares with Khalid in intelligence and descent.' Qiyasthus suggests an equality or close similarity between two things, one of which is taken as the criterion for evaluating the other.

50. Technically, qiyas is the extension of a Shari`ah value from an original case, or asl, to a new case, because the latter has the same effective cause as the former. The original case is regulated by a given text, and qiyas seeks to extend the same textual ruling to the new case. It is by virtue of the commonality of the effective cause, or `illah, between the original case and the new case that the application of qiyas is justified.

51. A recourse to analogy is only warranted if the solution of a new case cannot be found in the Qur'an, the Sunnah or a definite ijma`. For it would be futile to resort to qiyas if the new case could be resolved under a ruling of the existing law. It is only in matters which are not covered by the nusus and ijma` that the law may be deduced from any of these sources through the application of analogical reasoning.

52. In the usage of the fuqaha`, the word 'qiyas' is sometimes used to denote a general principle. Thus one often comes across statements that this or that ruling is contrary to an established analogy, or to a general principle of the law without any reference to analogy as such.

53. Analogical deduction is different from interpretation in that the former is primarily concerned with the extension of the rationale of a given text to cases which may not fall within the terms of its language. Qiyas is thus a step beyond the scope of interpretation. The emphasis in qiyas is clearly placed on the identification of a common cause between two cases which is not indicated in the language of the text. Identifying the effective cause often involves intellectual exertion on the part of the jurist, who determines it by recourse not only to the semantics of a given text but also to his understanding of the general objectives of the law.

54. Since it is essentially an extension of the existing law the jurists do not admit that extending the law by the process of analogy amounts to establishing a new law.Qiyas is a means of discovering, and perhaps of developing, the existing law. Although qiyas offers considerable potential for creativity and enrichment, it is basically designed to ensure conformity with the letter and the spirit of the Qur'an and the Sunnah. In this sense, it is perhaps less than justified to call qiyas one of the sources(masadir) of the Shari`ah; it is rather a proof (hujjah) or an evidence (dalil) whose primary aim is to ensure consistency between revelation and reason in the development of the Shari`ah. Qiyas is admittedly a rationalist doctrine, but it is one in which the use of personal opinion (ra'y) is subservient to the terms of the divine revelation. The main sphere for the operation of human judgement in qiyas is the identification of a common `illah between the original and the new case. Once the`illah is identified, the rules of analogy then necessitate that the ruling of the given text be followed without any interference or change. Qiyas cannot therefore be used as a means of altering the law of the text on grounds of either expediency or personal preference.

55. The jurist who resorts to qiyas takes it for granted that the rules of Shari`ah follow certain objectives (maqasid) which are in harmony with reason. A rational approach to the discovery and identification of the objectives and intentions of the Lawgiver necessitates recourse to human intellect and judgment in the evaluation of the ahkam. It is precisely on this ground, namely the propriety or otherwise of adopting an inquisitive approach to the injunctions of the Lawgiver, referred to asta`lil, that qiyas has come under attack by the Mu`tazilah, the Zahiri, the Shi`i and some Hanbali ulema. Since an enquiry into the causes and objectives of divine injunctions often involves a measure of juristic speculation, the opponents of qiyas have questioned its essential validity. Their argument is that the law must be based on certainty, whereas qiyas is largely speculative and superfluous. If the two cases are identical and the law is clearly laid down in regard to one, there is no case forqiyas, as both will be covered by the same law. If they are different but bear a similarity to one another, then it is impossible to know whether the Lawgiver had intended the subsidiary case to be governed by the law of the original case. It is once again in recognition of this element of uncertainty in qiyas that the ulema of all the juristic schools have ranked qiyas as a 'speculative evidence'. With the exception, perhaps, of one variety of qiyas, namely where the `illah of qiyas is clearly identified in the text, qiyas in genera) can never be as high an authority as the nass or a definite ijma`, for these are decisive evidences (adillah qat`iyyah), whereasqiyas in most cases only amounts to a probability. It is, in other words, merely probable, but not certain, that the result of qiyas is in conformity with the intentions of the Lawgiver. The propriety of qiyas is thus always to be measured by the degree of its proximity and harmony with the nusus. In our discussion of the methodology of qiyas it will at once become obvious that the whole purpose of this methodology is to ensure that under no circumstances does analogical deduction operate independently of the nusus. It would be useful to start by giving a few examples.

1. The Qur'an (al-Jumu`ah, 62:9) forbids selling or buying goods after the last call for Friday prayer until the end of the prayer. By analogy this prohibition is extended to all kinds of transactions, since the effective cause, that is, diversion from prayer, is common to all.
2. The Prophet is reported to have said, 'The killer shall not inherit [from his victim].' By analogy this ruling is extended to bequests, which would mean that the killer cannot benefit from the will of his victim either.
3. According to a Hadlth, it is forbidden for a man to make an offer of betrothal to a woman who is already betrothed to another man unless the latter permits it or has totally abandoned his offer. The `illah of this rule is to obviate conflict and hostility among people. By analogy the same rule is extended to all other transactions in which the same `illah is found to be operative.

56. The majority of ulema have defined qiyas as the application to a new case far`, on which the law is silent, of the ruling (hukm) of an original case (asl) because of the effective cause (`illah) which is in common to both. The Hanafi definition of qiyas is substantially the same, albeit with a minor addition which is designed to preclude certain varieties of qiyas (such as qiyas al-awla and qiyas al-musawi, [q.v.]) from the scope of qiyas. The HanafI jurist, Sadr al-Shari`ah, in his Tawdih,as translated by Aghnides, defines qiyas as 'extending the (Shari`ah) value from the original case over to the subsidiary (far`) by reason of an effective cause which is common to both cases and cannot be understood from the expression (concerning the original case) alone. The essential requirements of qiyas which are indicated in these definitions are as follows:

1. The original case, or asl, on which a ruling is given in the text and which analogy seeks to extend to a new case. i) The new case (far`) on which a ruling is wanting.
2. The effective cause (`illah) which is an attribute (wasf) of the asl and is found to be in common between the original and the new case.
3. The rule (hukm) governing the original case which is to be extended to the new case.

57. To illustrate these, we might adduce the example of the Qur'an (al-Ma'idah, 5:90), which explicitly forbids wine drinking. If this prohibition is to be extended by analogy to narcotic drugs, the four pillars of analogy in this example would be:

wine drinking	taking drugs	the intoxicating effect	prohibition
asl	far`	`illah	hukm

58. Each of the four essentials (arkan) of analogy must, in turn, qualify a number of other conditions which are all designed to ensure propriety and accuracy in the application of qiyas. It is to these which we now turn.