Qiyas ( قياس ) is the Arabic term for analogy, this is a type of logical procedure whereby a person will attempt to apply a specific law or truth to a different situation with the intention of learning a new truth.
What is Qiyas?
An example of Qiyas would be this, lets imagine all red apples are sweet, then someone asks about green apples, because you know about red apples, you could say that green apples are also sweet as they are very similar to red ones. This type of logic is a form of inductive logic, which means that you are starting with a specific truth, and trying to work back to a general truth, then apply to a different specific example.
It has four stages, which are as follows:
1. The original case (asl), on which a ruling is given in the text and analogy seeks to extend it to a new case.
2. The new case (far’), on which a ruling is needed.
3. The effective cause (‘illah), which is an attribute (wasf) of the original case and it is found to be in common between the original and the new case.
4. The rule (hukm), governing the original case which is to be extended to the new case.
A classic example that is often cited is that of wine and drugs, they will say:
Asl – wine drinking
Far’ – taking drug
‘Illah – intoxicating effect
Hukm – prohibition
However this is not correct, as this is not Qiyas, as in this example, intoxicants are forbidden, and this is a general rule, and therefore any intoxicant is forbidden, so the above example is actually not qiyas but deduction, or simply following the rule we already have. This situation is often cited as an example of Qiyas, however it does not demonstrate qiyas at all.
What are the opinions of Qiyas?
There is no clear justification for this type of logic from the Quran, qiyas was felt necessary by some Mujtahids who could not find any applicable rules from the Quran or Sunnah, so they had to use what was available to generate more rulings to meet demand for questions they were being asked.
The most famous proponent of Qiyas was Abu Hanifah, he was an early jurist who championed Qiyas, his books are numerous and there is no doubt he held a positive view on Qiyas.
There was significant opposition to Qiyas, both historically and in modern times. At the time of Abu Hanifa, the main bulk of Muslims subscribed to the Mutazilite school of thinking, which was deeply rationalist and therefore had no respect for Qiyas which was seen as “guessing”. Other Muslims of the time included the Shia, who also completely rejected the notion of Qiyas, the Shia Imams at that time were initially Imam Muhammad Al Baqir AS after his death was Imam Jafar Al Sadiq. There are extensive narrations from them discussing Abu Hanifa’s views on Qiyas. In Al Kafi we find many narrations that liken Qiyas (analogy) to innovations in the religion :
H 175, Ch. 19, h 20
Ali ibn Ibrahim has narrated from his father from Ahmad ibn ‘Abdallah al-‘Aqili from ‘Isa ibn ‘Abdallah al-Qurashi who has said the following.
“Once abu Hanifah came to see Imam abu ‘Abdallah (a.s.) who said to abu Hanifah, “O abu Hanifah, do you practice analogy as I hear you do?”
Abu Hanifah replied, “Yes, I do practice analogy.” The Imam then said to him, “Do not practice it because the first person who used analogy was Satan when he said, “Lord, you have created me from fire and created him from clay.” He analogized fire with clay. If he would have analogized the light in the clay and fire he would have learned about the difference between the two lights and the excellence of one over the other.”
H 170, Ch. 19, h 15
Muhammad ibn ’Isma‘il has narrated from al-Fadl ibn Shadhan from Safwan Yahya from ‘Abd al-Rahman ibn al-Hajjaj from Aban ibn Taghlib from abu ‘Abdallah (a.s.) who has said the following.
“The Sunnah, tradition of the holy Prophet (s.a.) can not be leaned through analogy. Consider a woman has to make up for her fast missed due to menses but she does not have to make up for the prayers that she would miss in such times. O Aban, the use of analogy destroys religion.”
There were also loud criticisms from Sunni groups, particularly from Ahmad Ibn Hanbal, Dawud al-Zahir, and Ibn Hazm.
Some have said, what is the difference between Aql and Qiyas? The difference is both simple, but significant :
Aql is deductive logic eg you start with a general law from the Quran or sunnah, then deduce a new ruling on a specific example that is covered by the general law.
Qiyas is inductive logic, this is where you start with a ruling, try to guess the general law, then apply the general law to a new specific case.
So essentially Qiyas does not lead to a certain logical truth, and is based on opinion and guesswork, hence the serious criticism it receives.