About this (theory of) correctness Muhammad ibn Abdi'l-Karim...

About this (theory of) correctness Muhammad ibn Abdi'l-Karim ash-Shahrastani writes: A group of theorists hold that in matters where ijtihad (research) is applied there is no settled view about permissibility or otherwise and lawfulness and prohibition thereof, but whatever the mujtahid (the researcher scholar) holds is the order of Allah, because the ascertainment of the view of Allah depends upon the verdict of the mujtahid. If it is not so there will be no verdict at all.

And according to this view every mujtahid would be correct in his opinion. (al-Milal wa'l-nihal, p.98) In this case, the mujtahid is taken to be above mistake because a mistake can be deemed to occur where a step is taken against reality, but where there is no reality of verdict, mistake has no sense.

Besides this, the mujtahid can be considered to be above mistake if it is held that Allah, being aware of all the views that were likely to be adopted has ordained as many final orders as a result of which every view corresponds to some such order, or that Allah has assured that the views adopted by the mujtahids should not go beyond what He has ordained, or that by chance the view of every one of them would, after all, correspond to some ordained order or other.

The Imamiyyah sect, however, has different theory, namely that Allah has neither assigned to anyone the right to legislate nor subjected any matter to the view of the mujtahid, nor in case of difference of views has He ordained numerous real orders. Of course, if the mujtahid cannot arrive at a real order then whatever view he takes after research and probe, it is enough for him and his followers to act by it. Such an order is the apparent order which is a substitute for the real order.

In this case, he is excused for missing the real order, because he did his best for diving in the deep ocean and to explore its bottom, but it is a pity that instead of pearls he got only the sea-shell. He does not say that observers should except it as a pearl or it should sell as such. It is a different matter that Allah who watches the endeavours may price it at half so that the endeavour does not go waste, nor his passion discouraged.

If the theory of correctness is adopted then every verdict on law and every opinion shall have to be accepted as correct as Maybudhi has written in Fawatih: In this matter the view adopted by al-Ash`ari is right. It follows that differing opinions should all be right.