This article was published on the Shiapedia, a website that was run by Shaykh Abd al-Hakeem Carney (d. 2007). After his demise, the domain and hosting services were not renewed and the website vanished. Soon after his death, someone had backed up his entire website and I had downloaded all the articles – around 60-70 – from this backup.
Al-Istishab (الإستصحاب) is one of the most important and oft-used principles in usul al-fiqh. It is one of the four major “procedural principles” (al-usul al-amaliyyah/الأصول العملية) that are used by jurists to determine what obligations a person has in a situation of doubt. It is often translated as “the presumption of continuity.”
Istishab comes from the same morphological route as the word sahib, meaning companion. Istishab literally means “seeking companionship.” Juristically, istishab applies in a situation where a person was in a state of certainty about a certain state of affairs and then doubts whether or not that state of affairs still holds true. The principle dictates that a person assume that state of affairs still holds true. For example, if a person knew that a piece of clothing was clean, and then doubted whether or not it was still clean, they would assume that it is still clean. Because this principle can see application in any subject matter of Islamic law, it is studied as part of usul al-fiqh, rather than al-qawa’id al-fiqhiyyah.
The state of affairs that is “continued” by istishab is called the mustashab (مستصحب).
Istishab is usually said to have four “pillars”, which are the conditions required for it to go into effect:
1) Past certainty (اليقين بالحدوث). The person must have certainty about the past state of affairs. This does not necessarily mean that they must have actual, epistemological certaitny. The past state of affairs must be confirmed either by direct certainty, or by some evidence that is assigned legal value in Islamic law. For example, if two just witnesses (whose testimony is accepted in Islamic law) bore witness that a piece of clothing was ritually clean, and then a third person doubts if the thing is still clean, they would still assume that it is clean
2) Doubt in continuity (الشك بالبقاء). The person must be in doubt about the continuinity of the state of affairs. Istishab is an apparent ruling, meaning that it is a ruling that only operates when a person is in doubt. Following the previous example, if the person knew that their clothes were ritually clean and knows that they are no longer ritually clean, then there is no space for this principle to operate. It is also necessary that the time of doubt be connected to the time of certainty; if one had certainty their clothes were ritually pure, then knew they weren’t, and then doubted if the clothes were still ritually impure, they could not use istishab of the original state of ritual purity.
3) Unity of the Proposition Concerning the Thing Known and the Thing Doubted (وحدة القضية المتيقنة و المشكوكة). What this means is that the state of affairs that was known before must be the same state of affairs that is doubted know. For example, a person knows that the clothes owned by Zayd are ritually pure, and he doubts if the clothes owned by ‘Amr are ritually pure. There is no place for istishab here, since the thing that was known and the thing that is doubted are seperate. The proposition must be the same, such as the proposition “Zayd’s clothes are ritually pure.” That proposition must be known to be true previously, and that same proposition has to be doubted now, for istishab to be applied and for Zayd’s clothes to be still ruled ritually pure.
4) That the state of affairs assumed to be continued has a legal effect (كون الحالة السابقة في مرحلة البقاء ذال أثر مصجج للتعبد ببقائه ). This means that istishab only applies in legal matters. If one knows, for example, that Zayd was wearing a green shirt today, and then one doubts if he is still wearing a green shirt, istishab would not apply, as there is no legal relevance to him wearing a green shirt. This is important, because most scholars of usul al-fiqh will argue that one cannot use istishab unless the state of affairs that one will assume is still continuing on the basis of istishab has direct legal value. For example: let us say that we have a large container of water in a house, large enough that it does not become impure by coming in contact with impurity (what is called kurr water). The house is locked and nobody else can come in. We then start to doubt if some of the water has evaporated, and whether or not that water is still of such a quantity that it does not become ritually impure by coming in contact with impurities. We go into the house and we realize we don’t know where the water is. We search and we eventually find a container of water. Rationally, since we know that nobody else has come into the house and there’s no possible way that somebody could have brought another container of water in, we would assume that this is the same water. By istishab, we would assume that it is still kurr, and so it would not become impure if it came in contact with something impure. However, the assumption that this is the same water is based on reason, and not based on any legal evidence. For us to do istishab of the previous water being kurr, we have to make this rational assumption. But because the thing that one is doing istishab with must have a direct legal effect, ‘without recourse to a rational intermediary’ such as the one in the previous example. In other words, the legal effect of istishab has to be applied directly, without any kind of ratoinal intermediary. When istishab is applied via some kind of rational or otherwise non-legal intermediary, it is known as al-asl al-muthbit (الأصل المثبت). The vast majority of Shi’ite jurists reject the efficacy of al-asl al-muthbit.
There are a number of legal evidences for istishab, and it is a principle that is used by all schools of law within Twelver Shi’ism.
The primary evidence is the hadith of Imam as-Sadiq, which is considered sahih and is narrated by Zurarah. He asked Imam as-Sadiq about whether or not a person who doubts if they have slept has to do wudhu again (since sleep invalidates wudhu):
لا حتى يستيقن انه قد نام حتى يجئ من ذلك أمر بين و إلا فإنّه على يقين من وضوئه و لا ينقض اليقين أبداً بالشك و لكن ينقضه بيقين آخر
No, not until he is absolutely certain that he has slept. This is because he was certain that he was on wudhu, and certainty is never broken by doubt. Certainty is only broken by another certainty.
A secondary evidence is derived from sirat al-‘uqalah, “the way of rational people.” This principle is not based on a belief in the efficacy of natural reason in religious law. Rather, “the way of rational people” indicates something that rational people simply do. The fact that many people do something is not, in and of itself, a source of Islamic law. However, if it is known that rational people normally do a thing, and that this thing is a universal practice amongst all people, and there is nothing within the Qur’an or the statements of the Prophet or Imams prohibiting people from doing it, then this implies a tacit approval on the part of the lawgiver. It is said that rational people will normally assume that something is still the case until proven otherwise, and there is no prohibition on the part of the Lawgiver for this practice. Therefore, Islam gives its tacit concent to it, and it is something a person is allowed to act upon.
Scholars have differed about how to classify istishab. It has been mentioned that istishab is a hukm zahiri, and the hukm zahiri, which is a legal ruling that operates in a situation of doubt. It has two general types:
- An amarah (أمارة). An immarah is a hukm zahiri that operates on the basis of probability. The legal value of a reliable person’s report is considered an amarah, since it operates under the assumption that reliable people normally give reliable reports.
- An asl (أصل). An asl is a hukm zahiri that is not based on probability. An example would be the principle that everything is ritually pure until proven otherwise. Obviously, most things are not always ritually pure; the probability has nothing to do with it, but rather the rule is made in order to give ease to people in their daily religious lives.
The question of where to categorize istishab has been a somewhat vexing one. It is argued by most that it is not an amarah, since the probablitity issue does not seem to play into it. If it is an asl, however, then it is a special one. For a normal asl delimits and defines the reality (واقع) of a given situation, but istishab is not considered to do this. It orders a person to act as if they have knowledge that the state of affairs still holds, without actually saying that the state of affairs ‘does’ still hold. An asl that defines the reality of a state of affairs is called a asl ihrazi (أصل إحرازي) or an asl muhriz (أصل محرز). Istishab is usually classified as an asl ghayr muhriz (أصل غير محرز) because of its intermediate state.
What this means in practice is that istishab takes precedence over an amarah, but does not take precedence over another asl. So, the principle of purity, which is an amarah, confirms that anything is ritually pure until proven otherwise. However, if a person knew from before that something was ritually impure, then istishab would apply. However, if it came in conflict with another asl, then that asl would take precedence. The reason for this is that an asl ihrazi defines the reality of a situation, and so negates the second pillar of istishab.
Types of Istishab
There are many other uses of istishab, which have been listed out below:
- Istishab al-Kulli (إستصحاب الكلي)
- Istishab as-Sababi wa al-Musabbabi (إستصحاب السببي و المسببي)
- Istishab al-Mawdu’at al-Murakkabah (إستصحاب الموضوعات المركبة)
- Istishab at-Ta’liqi (الإستصحاب التعليقي)
Istishab al-Kulli (إستصحاب الكلي)
A common type of istishab that is debated amongst religious scholars is istishab al-kulli (إستصحاب الكلي).
A kulli (كلّي) is any kind of general category, such as “animal” or “human being” or any category that can be applied to multiple entities. istishab al-kulli is a care where the mustashab is not a single entity, but is some kind of general category. For example: let us say that some fluid comes out of a man, and he is not sure whether it is urine or whether it is semen. If it is urine, he is in a state of minor ritual impurity. If it is semen, then he is in a state of major ritual impurity. Either way, he is in a state of ritual purity. Now, let us say that he does wudhu, which eliminates minor ritual impurity. However, if the fluid that came out of him was semen, then he would still be in a state of ritual purity. We would therefore use istishab, not of the major or minor ritual impurity, but of the ‘general’ category of ritual impurity. According to some scholars, he would still not be able to pray until he has performed ghusl, the full body bathing that removes major ritual impurity.
The reason for this is that a general category of “ritual” impurity has been extracted and derived from the possibility of being in minor or major ritual impurity. Each one is a type of ritual impurity; if a person is in major or minor ritual impurity, he is obviously in some kind of state of ritual impurity. The general category of “ritually impure” applies in both circumstances. Now in the example we have given, we are certain that, one way or another, this man is in a state of ritual impurity. It does not matter whether it is major or minor; the point is he is ritually impure. As such, the first pillar of istishab has been fulfilled: past certainty. Once he has done his wudhu, however, we doubt: has his ritual impurity been lifted or not? We are not sure, because it is possible he was in a state of major ritual impurity, which would not be lifted by mere wudhu. He may not have been in major ritual impurity at all; as such, we do not do istishab of major ritual impurity, but rather do istishab of “ritual impurity” in general. The only way this man could be certain that he is no longer in ritual impurity is if he does both wudhu and ghusl, thereby removing both types of ritual impurity, making him ritually pure.
To take another example, we see somebody enter the mosque. We are not sure if it is Zayd or ‘Amr, but we know that a human being has entered the mosque. Later on, we see ‘Amr outside of the mosque. We are not sure if he was the one who had gone into the mosque in the first place, or if it was Zayd. So while we are certain that Amr is not in the mosque, we are not sure if there is still a human being in the mosque. If there was some legal ruling associated with there being a human being in the mosque, we could do istishab of there being a human being in the mosque.
Traditionally, there are three types of istishab al-kulli:
First Type (القسم الأول من إستصحاب الكلي)
An example of the first type is this: We know that either Zayd or ‘Amr has entered the mosque, and then we doubt if Zayd or Amr are still in the mosque. ٍThis type of istishab can run into problems under some circumstances, depending on a jurists philosophical views. For example, based on what is known as the position of the “Man from Hamadan”, an anonymous person who Ibn Sina had a discussion with concerning some philosophical issues, then there is no problem. The “Man from Hamadan”‘s view was that the relationship between a universal category (like human being) and the individuals that make it up is like the relationship between a father and his several sons: his “fatherhood” is multiplied across his several sons, and he is as much of a father to one as he is to the other. In this case, the category of “human being” would be multiplied across the number of human beings that we are discussing, in this case Zayd and Amr. This category exists in them, but it still remains a single category; it is multiple across the individuals that make it up, and it is singular in terms of what is united between them. This means that the universal category has a seperate, individual existence of its, independent of the individuals that make it up. Now, in our example, we know that this category of being entered the mosque, in the form of Zayd or Amr, and then we doubt if it has left in the form of Zayd or ‘Amr. Since the universal category of “human being” has an existence of its own, the pillars of istishab have been met: we know that a “human being” entered, and we doubt if a “human being” has left, and so the principle applies.
Similarly, if we do not follow the position of the “Man from Hamadan,” but we follow the position of Muhammad Baqir as-Sadr which argues that the universal is taken merely as a “reflection” of the individuals that make it up, then we can also do istishab in this case. Even though he does not believe that the universal has a singular existence that becomes multiplied across the individuals that make it up, nonetheless the universal category does have a seperate existence that is not identical with the individuals that make it up. We can therefore do istishab of that universal category as a reflection of the universals that make it up.
However, other scholars argue that doing istishab of the universal is based on doing istishab of the individuals that make up that universal. This was the apparent position of Muhaqqiq al-‘Araqi. If we follow this position, then we run into a problem. For we cannot do istishab of Zayd going into the mosque, because we have no certainty he was there. Nor can we do istishab of ‘Amr being in the mosque, because we don’t know that he was there either. Since we cannot do istishab of either Zayd or Amr, then if we believe the existence of their being a human being in the mosque depends on either Zayd or Amr being there, we could not do istishab of a human being existing inside the mosque.
Second Type (القسم الثاني من إستصحاب الكلي)
An example of this is the one given in the introduction, where a person is not sure whether or not they are in major ritual impurity or minor ritual impurity, but do know that they aer in some kind of state of ritual purity. In this case, the presence of the universal is known by al-ilm al-ijmali. According to as-Sadr, there is no problem in istishab applying in such a case, since there is past knowledge about the thing which known by al-ilm al-ijmali, namely the general category of “ritual impurity”, and doubt in its continuation.
Third Type (القسم الثالث من إستصحاب الكلي)
We know Zayd has entered the mosque. We then know that he left. However, it is possible that another person, ‘Amr entered the mosque while Zayd was there. If we follow the model of the “Man from Hamadan”, then we know that the universal category of “human being” was still in the mosque, and we are not sure if that universal is still there after Zayd has left. We can phrase this in other terms: we could say we have two pieces of knowledge: one is the knowledge we have of Zayd being in the mosque, and the second is the knowledge we have of a human being in the mosque. If we follow the Man from Hamadan’s position, then the second knowledge has an independent existence of its own; even though our knowledge of their being a human being in the mosque was caused by Zayd’s presence, it takes on a life of its own as a singular, unitary entity. We doubt if it is still there, and so we do istishab.
However, if the universal category is believed to depend on the individuals that make it up, either in the way of as-Sadr or al-‘Iraqi, then istishab would not apply in this circumstance. This is because he only reason we believed there was a “human being” in the mosque was because Zayd was in the mosque. Now Zayd has left, and so the basis for our original certainty that there was a human being in the mosque was gone. The second pillar of istishab has not been fulfilled, and so we would not do istishab of there being a human being in the mosque.
Istishab as-Sababi wa al-Musabbabi (الإستحصاب السببي و المسببي)
Occasionally two usages of istishab can contradict each other. For example, let us say that a person washes a ritually impure shirt in a container of water. The water was known to be kurr (so large that it does not become impure when it touches ritually impure things), but the person washing it doubts whether or not it is still kurr. By istishab, he would assume that the water is still kurr, and therefore the water does not become impure when he washes the shirt in it. If the water had not been kurr, then placing a dirty shirt in it would have made that water impure, and then that water could not have been used to make the shirt clean; the shirt would, therefore, remain dirty. However, since it is ruled as being kurr, the water does not become impure, and so the shirt washed in it becomes clean.
However, if we analyze this issue more closely, we see there is a problem. Since the person doubted whether or not the water was kurr he is, by extension, doubting whether or not he has made the shirt clean. For if the water was not clean, the shirt will not be clean. If we do a second istishab of the shirt’s ritual impurity, then the shirt would be ruled ritually impure, because the person is not certain it has become clean.
As a result, we have collision of two istishabs:
- Istishab of the water being kurr’, which necessitates that the shirt washed in it becomes clean.
- Istishab of the shirt being impure, which necessitates that the shirt washed in it doesn’t become clean.
This collision, however, is resolvable. When we have a collision of two istishabs, we look to see which one has an effect on the other, and which one does not. In this case, we see that once the istishab of the water being kurr is applied, then there is no longer any doubt in whether or not the shirt is clean. There is therefore no more room for the second istishab to operate, because the second pillar (doubt) has not been fulfilled. However, if we apply the second istishab, it has no effect whatsoever on the first one. The first istishab, therefore, is given primacy over the second, and there is no collision. The shirt is clean.
The istishab that effects the other istishab is called al-istishab al-sababi (الإستصحاب السببي), the “causal istishab“, because it causes the second istishab to become nullified. The one that is effected is called (الإستصحاب المسببي), the “caused istishab“, because its application depends on the results of another istishab.
Istishab fi al-Mawdu’at al-Murakkabah (الإستصحاب في الموضوعات المركبة)
Every ruling has what is called a subject (mawdu’/موضوع); this is the thing that “activates” the ruling. For example, the “subject” of the obligation for performing hajj is the person who is able to perform hajj. If a person is not able to perform hajj, then they are not “subject” to the obligation of hajj. The “subject” is the condition that must be fulfilled for the ruling to become active.
Sometimes the subject of a ruling is composed of a number of different elements. For example, let us say we have some water, and this water comes in contact with something impure. It becoming impure is based on two “subjects”: that the water comes in contact with something impure, and that the water is not kurr. The subject is thereby composed of two elements. This is called a “composite subject” (mawdu’ murakkab/موضوع مركب).
Now, let us suppose that we have some water, and we know the water is now no longer kurr, but that it was. We also know that it came in contact with something ritually impure. Can we do istishab of it being kurr until the time that it came in contact with the ritually impure thing, thereby making the water still ritually pure? There are a number of scenarios for this:
We know when the water ceased being kurr and we know when it came in contact with the ritual impurity. Obviously, no istishab applies in this case, because the second pillar (doubt) has not been obtained.
We don’t know when the water came in contact with the ritual impurity. We know that the water ceased being kurr at noon, and let us say it’s three o’clock in the afternoon now. Now, we could theoretically do istishab of it being kurr until the time it came in contact with the ritual impurity, thereby making the water pure. However, Ayatullah Muhammad Baqir as-Sadr argues that there is a problem. We have said that we want to do istishab of it being kurr until the time it came in contact with the ritual impurity; but it is entirely possible that it came in contact with the ritual purity at the same time it ceased being kurr. We know the time it ceased being kurr was at noon time. Therefore, it is entirely possible that this vaguely defined time of “when it came in contact with the ritual impurity” is the very same time that we know the water ceased being kurr. ‘If’ the time of “when it came in contact with the ritual impurity” is the same as the time the water ceased being kurr, then there is no doubt about the continuity of it being kurr until that time. Therefore, the second pillar (doubt) has not been established, and so we cannot do istishab. We can frame it like this:
If (time water came in contact with ritual purity = noon) and (time water ceased being kurr = noon) then there is no doubt that the water ceased being kurr at the time it came in contact with the ritual purity.
In other words, we have doubt; we have doubt about whether or not there is any doubt to begin with about the water still being kurr at the time it came in contact with ritual purity.
We know when the water came in contact with the ritual impurity, but we do not know when the water ceased being kurr. In this case, there is no problem in applying istishab. We don’t know when it ceased being kurr, and so we are not bound in the way that we were in the previous example. The time of contact is defined, and it is not clear if the water ceased being kurr before then or after; the pillars of istishab have been obtained, and so there is no problem.
Based on this, Ayatullah Muhammad Baqir as-Sadr, however, offers an exception to the first scenario, where we do not know the time the water ceased being kurr, nor do we know when the water came into contact with the ritual impurity. Let us say that we know that the water may have ceased being kurr at noon, one o’clock, or two o’clock. However, we know that it could only have come in contact with the ritual impurity at noon or one o’clock. The scope of doubt for the time it ceased being kurr is wider than the scope of doubt for when it came in contact with the ritual impurity. We know that the water may very well have continued being kurr until after two o’clock, and so the pillars of istishab have been obtained, and there is no problem.
Ash-Shaykh al-Akhund, author of Al-Kifayah, did not entirely accept this position. It was noted above that it is necessary that the time of doubt be connected to the time of certainty. Let us suppose that it is possible the water ceased being kurr between one o’clock and three o’clock and that it is also possible that it came into contact with a ritual impurity during the same period. We know, therefore, the time of contact with ritual impurity and the time of the water ceases to be kurr by al-ilm al-ijmali, insofar as we know that it occurred either during the hour of one o’clock or the hour of two o’clock. As a result, we have knowledge during those two hours, and therefore the time of doubt is split from the time of certainty. What we would be wanting to do in this case is to do istishab of the water being kurr until three o’clock, since that’s the outermost limit that the time of contact with ritual impurity occured. Our time of certainty for the water being kurr is before one o’clock. But as for the period between two and three o’clock, we know by al-ilm al-ijmali that the water ceased being kurr during that period, and so the time of doubt is not connected to the time of certainty. We could only do istishab of the water being kurr up until two o’clock.
As-Sadr rejects this argument, however. He argues that we are attempting to do istishab up until the time that the contact with the ritual impurity occured, ‘not’ until the time that the ritual impurity becomes known through al-ilm al-ijmali. Since the time it occured could be later than two o’clock, we can do istishab up until that time period.
Istishab at-Ta’liqi (الإستصحاب التعليقي)
Al-Istishab at-Ta’liqi (الإستصحاب التعليقي) is a subdivision of Istishab. This is when the mustashab is not a state, but rather a conditional proposition. For example, if a hadith says “If grapes are boiled, they become impermissible to drink”, one may question: does this still apply when the grapes have dried and become raisins? If the legal evidences ar classified by such a conditional proposition (“If” or “when” or what have you), then many jurists (such as Ayatullah Muhammad Baqir as-Sadr argue that it is permissible to do istishab of that conditional proposition.