The Imamis, generally speaking, inwardly believe in the truth of Islam, except for those among them who are heretics. Indeed, many of the Shiite shaykhs inwardly hold beliefs different from theirs: some are philosophizing heretics, while others hold yet different views.

Some people say:

“The author of this book does not himself (1) inwardly adhere to their doctrine. He was compelled to profess this school outwardly because of the worldly advantage it afforded him.”

This is said (2) by more than one person who loves and esteems the author of this book.

It is most likely that he and others like him (3) are bewildered, caught between the doctrines of the philosophers and those of their predecessors among the speculative theologians. The discussions found in their books reveal their confusion and inconsistency. This is why the author of this book holds heretics such as al-Tūsī, Avicenna, and their likes in high esteem, while also esteeming the shaykhs of the Imamis. Consequently, many Imamis denounce and revile him, saying:

“He does not follow the path of the Imamis.”

The same holds true of the adherents of every religion: as a rule, you will find that their most distinguished men either embrace the true religion of Islam or become heretics. Thus, many Christian scholars are inwardly crypto-disbelievers and heretics, while some inwardly incline toward Islam because the corruption of Christianity has become evident to them.

If, then, it is assumed that the need for an infallible person has been established, the question remains which particular person he is. When an Ismāʿīli is called upon to identify his infallible authority and asked what evidence proves that this person is (4)