With respect to the first question - “What is the origin of Shi`ism?” -one may safely regard Shi'ism as a consequence that is natural to Islam, representing a thesis whose realization is imperative for the Call (or Mission of Islam1) if the latter's sound progress is to be assured.
It is possible for us logically to infer this thesis from the Call of Islam, led by the Prophet, because its formation was natural and due to particular circumstances. The Prophet had put into practice a revolutionary leadership, and drove for a comprehensive change of society, its conventions, structures and ideas. But the road to such a change was not to be a short one. It was long, extending the length of that deep spiritual chasm separating pre-Islam from Islam. The calling pursued by the Prophet had to begin with the man of pre-Islam in order to create a new being out of him; it was from the pre-Islamic world that the man of Islam would issue, carrying the new light to the rest of the world. This Mission had to extirpate every last root and vestige in him of pre-Islam.2
Within a short period of time, this remarkable leader was able to make quite amazing progress in the drive for change. But this drive had also to continue its lengthy path even after his death. The Prophet had known for some time that his term was nearing an end. He openly announced it at the “Farewell Pilgrimage.”3 Death hardly took him by surprise. That means that he had ample opportunity to ponder the fate of the Mission beyond his lifetime, even if we disregard the element of a liaison with the hidden world, or for that matter the direct Grace of God evinced by the Message revealed to him.4
In the light of this, we may note that the Prophet had before him three possible paths to choose from with respect to the future. First, the path of denial; second, the affirmative path (for example, consultation); third, appointment.5 These will constitute the three discussions to be taken up below.