To introduce this subject, we will examine the following:

1. If we are certain that a drop of blood or wine has dripped into a tumbler of water, we are clear that both tumbler and water have been rendered impure.

2. However, if there are two tumblers of water and we are certain that a drop of blood or wine has dripped into one of them, how should we respond with regard to purity and impurity?

Our knowledge in case (1) above is detailed - tafsili -whilst our knowledge concerning case (2) is only summary - ijmali. The difference is that in (1) there is no confusion or ambiguity regarding what is known, whilst in case (2) clarity and ambiguity are balanced. Clarity is represented by the certainty that there is a drop of blood or wine in one tumbler while ambiguity is represented by lack of knowledge as to which tumbler of water has been contaminated.

There are infinite examples of summary knowledge. For example, the teacher of a class may know that pupils have thrown a chair out of the window, but be uncertain as to which pupil did so. It may be clear that a neighbour's vehicle has bumped one's parked car but one may have no clear information as to which neighbour is responsible.

In chapter 7 'Certainty is not challenged by doubt', which dealt with 'detailed' knowledge, it was made clear that doubt is ignored when certainty is arrived at. That is because certainty has the value of 100%, while the value of doubt, by definition can never exceed 50%.

When certainty is achieved, shari’ah determines that one is accountable to act upon it. If, for whatever reason, one does not act upon certainty, one is in violation of Allah's laws.

In order to answer the question of 'how to respond' to summary knowledge, we need to differentiate between what is obligatory and what is prohibited. When someone is torn between two actions because he/she knows that one is obligatory but is not sure which, he/she must fulfil both to ensure security.

For example, if a traveller is unsure whether he/she meets the requirements for shortening the prayer, it is incumbent upon her/ him to offer the full as well as the shortened prayer. Or, if one entertains doubts that the Friday prayer offered by a particular congregation meets the essential requirements of such prayer, it is incumbent upon one to offer both the Zuhr and the Jum’ah prayer.

If someone has summary knowledge that one of two possible actions is prohibited, they must avoid them both. For example, if I know that either x or z was nursed by my mother and thus one is my sister by suckling, I am not permitted to marry either of them.

There are often more than two alternatives; for example, if one of ten sheep slaughtered on a particular day one did not meet shari’ah slaughter requirements, it is obligatory to avoid eating any of them.

So, what are the consequences of acting upon one option of summary knowledge? For example, concerning the above example of two tumblers of water, a person might make the assumption that one of the tumblers has not been contaminated and drink from it. This situation is unsafe because he/she might have consumed contaminated liquid, referred to as 'probable non-conformity' - mukhalafah ihtimaliyah. However, drinking both tumblers of water would constitute 'definitive non-conformity' - mukhalafah qat’iyah - a situation that represents outright disobedience to Allah.

Dissolution Of Summary Knowledge

In the above example of women who may have been suckled by the same nurse - if several reliable witnesses confirm that it was clearly not x who was suckled by the same nurse as oneself, the ambiguity is displaced by clarity. Certainty may also be brought about via one's senses - in the example of the polluted tumbler of water, if it is possible to detect the smell of wine in one tumbler clarity may be achieved.

The technical term for such clarification is referred to in jurisprudence as 'dissolution of summary knowledge' - inhilal al-‘ilm al-ijmali. Similarly, in the example of the slaughtered sheep above, if clarity is obtained that a specific sheep was not slaughtered in conformity with shari’ah, the remaining nine become permissible to consume.

In the study of Principles of Jurisprudence, there are various cases to be examined under the title 'dissolution of summary knowledge'; the few examples given above provide clear indication of this subject.