Before being able to discuss this subject we need first to define the words 'certainty' and 'doubt'. In Islamic jurisprudence, 'certainty' indicates absence of doubts as to the correctness of something. In other words, a matter is so clearly evident that no questions about it are entertained. The Arabic word for this is yaqin.

The degree of certainty expressed by the word yaqin is 100%. Probabilities of accuracy that appear to be between 99% and 51% are referred to as zann. Probabilities that are equal when the probability of existence or non­existence of things is equipoised - are referred to as shakk. Probabilities below 50% are referred to as wahm.

Statements based on shakk or wahm are not considered by the Islamic legal system. With regard to Zann, the closer it is to certainty the greater the consideration it will be given.

To appreciate the significance of yaqin, we refer to Qur'an:

"And thus, did we show Abraham the dominions of the heavens and the earth and that he might be of those who are sure." (Surah Al-‘An’am, 6:75)

In the Qur'an we learn that there are three levels of yaqin:

1. ‘Ilm al-yaqin - lit. to know with certainty. (Surah Takathur, 102:5).

2. ‘Ayn al-yaqin - lit. certainty itself. (Surah Takathur, 102:7).

3. Haqq al-yaqin - lit. absolute certainty. (Surah Al-Waqi’ah, 56:95).

Haqq al-yaqin is the level of certainty that is acquired when a spiritual and physical encounter - between a 'knower' and a 'known thing' – is experienced. This level of certainty leaves no room for any doubt whatever. Clearly, at this level, certainty is not challenged by doubt.

The following examples illustrate the application of this principle within the field of Islamic jurisprudence:

• Twenty years ago person A borrowed money from person B. Some time later A begins to entertain doubts as to whether the debt was repaid or not. In the absence of incontrovertible proof - documentation or witnesses that confirm that the debt was honoured, jurists will deem it not to have been. This is because there is certainty that the loan was made but no certainty that it was repaid.

• At 8 a.m., certain that he/she had made ablution - wudu' - and was in a state of 'ritual purity', the person occupies themself with work. At 1 p.m. uncertainty takes root as to the validity of their wudu'. Unless certain that anything that would negate the validity of wudu' has occurred, they have to presume the continuity of their former certainty.

• Knowing them to be clean and 'ritually' pure, a neighbour borrows towels. Once they have been returned, in the absence of physical evidence to the contrary, any suspicion regarding the cleanliness of the towels has to be ignored, and reliance placed upon the former certainty that the towels remain clean and 'ritually' pure.

The Basis Of This Principle

From Ahadith

Zurarah narrates from Imam al-Sadiq (‘a) that he asked 'If a person who is in the state of ritual purity dozes off for a few seconds is their wudu' invalidated?'

The Imam (‘a) replied, 'While the eye might close, the heart and ear might remain aware. Only when eye, ear and heart sleep is wudu' broken.'

Zurarah then asked, 'What if something at their side is moved without them feeling it?' Imam al-Sadiq (‘a) replied, 'Unless a person is certain that he/she fell asleep, they may presume the continuity of their previous wudu'. Never challenge certainty with doubt, for certainty is only dispelled when it is replaced by another certainty.'1

Both authenticity and content of this hadith are secure. Regarding authenticity, the 'chain' of its narrators is recorded as: Shaykh Al-Tusi from Husayn Ibn Saeed, from Hammad Ibn Isa, from Hariz Ibn Abdullah, from Zurarah.

The last sentence of the hadith clarifies that certainty can never be challenged by doubt. It is clear that this ruling is not restricted to issues of wudu' but is applicable to all areas of jurisprudence. This is also the view of Muhammad Kazim al Khorasani in Kifayat al-Usul, p. 389 and Muhammad Baqir al-Sadr in Durus fi ‘ilm al-Usul, Vol. 3, p. 442.

In Arabic grammar, the article 'al' may be applied to two different concepts:

1. Universality - lam al-jins

2. Reference to a previously mentioned subject - lam al-‘ahd

When the second concept is referred to, it is clear that that reference is being made to a specific subject. Thus, some jurists claim that the above hadith refers specifically to certainty of ablution not being challenged by doubt. Such jurists do not accept that this principle may be applied to other areas of jurisprudence. However, the majority of Imamiyah jurists believe that the article ‘al’ expresses universality and that claims to the contrary cannot be supported and are thus not valid.

Another hadith from Zurarah refers to six questions that he asked Imam al-Sadiq (‘a):

Question 1: 'When I noticed that blood from my bleeding nose had left a stain on my clothes I planned to wash it off before praying. However, I forgot to do that and only remembered it after having finished the prayer. What should I do?'

The Imam (‘a) answered: 'Clean your clothes and repeat the prayer.'

Question 2: ‘Even though I was certain that blood had stained my clothes I could find no trace of it and so offered my prayer. However, after the prayer I did find a bloodstain. What should I do?’

The Imam (‘a) answered: 'Clean your clothes and repeat the prayer.'

Question 3: ‘1 thought that blood had stained my clothing but as I could not find a stain I could not be certain. However, after the prayer I did discover a bloodstain.'

The Imam (‘a) answered: 'Clean your clothes, but you do not need to repeat the prayer.'

When I asked him why that was the case the Imam (‘a) replied, 'Because when you started your prayer, you were certain of the ‘purityn of your clothes and only later entertained doubts about it, and you may not challenge certainty by doubts.’

The other three questions2 that Zurarah asked are not included here because it is this third question that is relevant to our topic.

This hadith clarifies the general principle, 'Certainty may not be challenged by doubt', for when the Imam (‘a) replied, 'Because when you started your prayer you were certain of the "purity" of your clothes', he (‘a) validated 'presumption of the continuity of certainty' - the very core of this principle.

From Common Practice

Regardless of culture, background or religion, people commonly rely upon certainty unless presented with facts that dispel that certainty. The reason for this is that their 'degree' of certainty is 100% while probabilities or doubts appear to them to be less credible. Some scholars, support this on the grounds that it applies to human beings as well as to Allah's other creation.

For example, consider the biannual migrations of swallows, swifts and martins to Southern Africa and back, to nests they have established 6,000 miles apart. Many other species such as wildebeest and elk, salmon and eels also migrate. Their urge to return to far-off habitats is driven by the 'continuity of certainty' that it is the correct thing for them to do.

From Consensus

Al-Qarafi reports in Al-Foruq, Vol. 1, p. 111, that the consensus amongst jurists is to support this principle and to ignore doubts that assail certainty.

Ibn Al-Qayyim al-Jowzia in I’alam al-Muwaqein, Vol. 1, p. 295, also claims that there is consensus among jurists regarding this principle. He confirms that such consensus exists despite differences they might have concerning its detail.

Al-Nawawi, after quoting the prophetic hadith - 'When a person entertains doubt as to whether he/she has broken wind during prayer, they should ignore those doubts and continue their prayer unless they have actually heard the sound of wind being broken' - claimed this hadith to be an essential ruling of Islam. This means that no Muslim scholar is prepared to argue against it.

Muhammad Kazim al Khorasani in Kifayat al-Usul, p. 388, relates from Allamah Hilli in Al-Mabadi that the consensus amongst jurists is that if doubts are raised regarding the continuity of a ruling, it is imperative for them to confirm and support its continuity.

Essential Elements Of This Principle

Some scholars mention that up to seven different elements need to be present for this principle to be applied. However, we believe that it only requires the following four:

1. Certainty at the outset.

2. Doubts later arising concerning its continuity.

3. That both the certainty and doubt relate to a specific issue.

4. Issues in which the presumption of continuity impacts upon religious obligation.

The examples shown above illustrate the need for these four elements. For instance:

• The example of the loan - Certainty that the loan was made, doubt that it had been repaid, both certainty and doubt relate to the loan and the impact that this principle has regarding the religious obligation to repay loans.

• The example of wudu' - Certainty that the person was in a state of religious purity, doubt regarding that having been invalidated, both certainty and doubt relate to religious purity and the impact that this principle has regarding the religious obligation for prayer to be conducted in a state of religious purity.

It is worth mentioning that the Imamiyah, Hanafis and Shafi’is consider the principle of presumption of continuity to be an important 'tool' in itjtihad while the Malikis do not.

• 1. Wasa'il al-Shi’ah, Vol. 1, p. 245.
• 2. Tahzeeb al-Ahkam Vol. 1, p. 421.