Skip to content
Coordinates of ThoughtHome of Philosophy
Join
Discussion

Qiyās, kal va-chomer and legal analogy: defeasible reasoning with centuries of rules

Khalid Mahmood Awan Fellow
· 5 replies · 275 views
Logic & argumentIslamicJewishIslamic jurisprudenceH. L. A. HartIbn Sina#analogy#defeasible-reasoning#kal-vachomer#legal-reasoning#qiyas
Follow

I spent thirty-one years on the bench in Punjab. The reasoning I used most was neither deduction nor statistics. It was analogy: this case resembles that one in the respect that matters, so it should be decided the same way.

Islamic jurisprudence turned this into a disciplined method, qiyās. It has four parts: the original case with a known ruling, the new case, the ruling, and the effective cause (ʿilla) that links them. The textbook example: wine is prohibited, the effective cause is intoxication, so other intoxicating drinks share the ruling. Most of the hard work in uṣūl al-fiqh is about the ʿilla: how do you know which feature of the original case was the one that mattered?

What strikes me now, reading informal logic, is how plainly this is defeasible reasoning, and how openly the jurists said so. An analogy could be defeated by a stronger text, by a better-identified cause, or, for the Ḥanafīs, by istiḥsān, a considered preference to depart from strict analogy when it would produce an unjust result.

I'd like to compare notes with people from other legal traditions. How did your jurists discipline analogy? And did your logicians respect it or look down on it?

LikeReply
Follow5 replies

Members reply here. Reading is always free.

Sign in to reply

5 replies

  1. Rabbi Eliana Gutman

    Fellow

    Very close parallels in rabbinic law. Hillel's seven rules of interpretation open with kal va-chomer, the argument from lighter to weightier: if something holds in the lenient case, all the more so in the strict one. There is also gezerah shavah, linking two passages by a shared word.

    And there is a built-in limit I love, the principle of dayo: a conclusion drawn by kal va-chomer can be no stricter than the case it was drawn from. In other words the rabbis knew analogy could overreach and capped it. That is an argumentation scheme with a critical question attached, long before anyone used those terms.

  2. Hamza Qureshi

    Fellow

    The common law does the same thing under other names. A precedent binds only if the new case is not "distinguished", which is exactly a defeat condition: show that the feature which mattered in the old case is absent here. Hart's famous example of a rule banning vehicles from a park makes the point: a car clearly falls under it, but bicycles and toy cars need a judgement about what the rule was for, and Fuller, replying to Hart, added a war memorial built from an old military truck. That is your ʿilla question in English.

    Helpful · 1
  3. Layla Haddad

    Fellow

    On the logicians: in the Arabic tradition they were rather condescending. Ibn Sina and those who followed him classed analogy (tamthīl) among arguments that yield opinion rather than certainty, below demonstration. The jurists did not accept the demotion quietly. Ibn Taymiyya later turned it round in his refutation of the logicians, arguing, roughly, that the universal premise of a syllogism is itself no more secure than the analogy it was meant to improve on. Whether he was right is still argued about, but it's one of the sharpest defences of analogy I know.

    Helpful · 2
  4. Imam Bilal Hussain

    Fellow

    From the chaplaincy rather than the court: istiḥsān and maṣlaḥa are how I explain to colleagues that Islamic ethics is not a rule-following machine. When the hospital asks me whether something is permissible, I almost never deduce an answer. I reason from cases, and I say aloud what would change my view. Khalid's description of qiyās as openly defeasible is the most useful framing I have seen.

    Helpful · 3
  5. Khalid Mahmood Awan

    Fellow

    Thank you all. Eliana's dayo principle is the detail I'll keep: an explicit rule that the conclusion of an analogy cannot outrun its source. In court I would have called that common sense; it is better called a critical question. And Layla's point about the logicians explains a lot about why lawyers and philosophers in my country still talk past each other.