there is an overwhelming preponderance of jurists holding a certain view, that view is valid and binding, though not absolute.9 Ijmā‘ is said to be complete when all the jurists of a particular age have come to an agreement on a certain question, though according to some it is necessary that all of them should have passed away without changing their opinion on that question. Some go still further and assert that no Ijmā‘ is effective unless it is shown that no jurist born in that age has expressed a contrary opinion.

When Ijmā‘ is established on a point, its effect is that no single jurist is permitted to reopen it, unless some jurist of the age in which the Ijmā‘ came about had expressed a different view. One Ijmā‘ may, however, be repealed by another in the same age or in a subsequent age, with this reservation that the Ijmā‘ of the Companions of the Holy Prophet cannot be reversed by any later generation.10 Views differ as to whether or not, when there is disagreement on a question among the Companions, an Ijmā‘ upholding one view or the other is debarred. The fact that even a Companion may have made an error in forming a judgment is admitted on all hands, and therefore technically, there can be no objection to an Ijmā‘ which goes against the opinion of a Companion.

Two more points have to be elucidated in order to realize the full force of Ijmā‘. From what has been stated above, it would seem that a very large number of jurists would be needed for a valid Ijmā‘. It is, however, held that if three or even two of them take part in deliberating on a question, the Ijmā‘ is valid, while one jurist is of opinion that, if in any particular age there is only one jurist his solitary opinion would have the authority of Ijmā‘. And now we come to the most important question: What is the authority on which Ijmā‘ is to be based? According to the four great Imāms, it may be based on the Holy Qur’ān or on Ḥadīth or on analogy. The Mu‘tazilas, however, hold that it cannot be based on isolated ḥadīth or on analogy.11 They, and some others, hold that as Ijmā‘ is absolute, the authority on which it is based must also be absolute.

Ijmā‘ is only Ijtihād on a wider basis

It would thus be seen that it is a mistake to call Ijmā‘ an