—as when following the Messenger or those whose agreement constitutes consensus—then he follows on the basis of proof: his knowledge that the person followed possesses knowledge. This is not the imitation under discussion. Such imitation is obligatory, because it is known that the Messenger is protected from error and that those whose agreement constitutes consensus are protected from error. As for imitating a scholar where this is permissible, it is comparable to following evidence that yields a strong presumption, such as solitary reports and analogical reasoning. The imitator considers it highly probable that the scholar exercising independent judgment is correct, just as he considers it highly probable that an informant is truthful. There is, however, a difference between following a transmitter and following an opinion, which will be discussed elsewhere, Allah willing.

Following a transmitter is obligatory because he alone possesses knowledge of what he reports. An opinion, by contrast, can be arrived at through the same means by which its holder arrived at it. Moreover, errors in transmission are unlikely, since accurately preserving a report is easy; hence reports have been transmitted on the authority of women and ordinary people. Errors in reasoning, by contrast, are frequent because its methods are subtle and numerous. This is the accepted practice among those who permit accepting a report even when it is possible to consult the person on whose authority it is transmitted, but do not permit accepting an interpretation when it is possible to ascertain the evidence.

As for the former accepted practice, the scholars agree upon it. Hence they require following a report, whereas no one requires a person capable of examining the evidence to imitate a scholar. They differ only over whether doing so is permissible, since that person can acquire knowledge through the same means by which the scholar acquired it. This, then, is a general outline.