discipleofJesus:
I’m not sure I understand, why can’t anyone claim the caliphate after Ali Bin Abu Talib?
Because 'Ali Bin Abu Talib was the last caliph who was elected and governed by consultation of the Muslim ummah, as required by the Qur’an. All others after him are illegitimate because they did not meet this requirement.
What about Mu’awiya? Wasn’t he a legitimate caliph?
No, though Mu’awiya became the de facto caliph, he is not and never will be legitimate either in Sunni or Shi’a eyes, because he was not elected, and nor did he govern with the consulation of those governed. He seized and retained power in autocratic fashion.
Aren’t Muslims, when they have the opportunity, supposed to have a caliph who leads the Muslims always? i.e. that when they don’t have one, they are lacking a leader that they are meant to have?
Clearly, but a major hurdle to that would be political unity of the Muslim ummah. What good is having a caliph when Muslims are today divided into more than 60 separate countries, some arch enemies of each other, and in various other ways? That would be a toothless caliph if there ever was one.
That they believe he “embodies the spirit of the Prophet”? What do you mean by he “embodies the spirit of the Prophet”?
What I mean is that the Shi’a believe God’s guidance and inspiration passes infallibly from the Prophet (PBUH) down a long line of successors from his descendants, from among whom are chosen the Shi’a Imams. I’m not talking about the physical spirit of the Prophet (PBUH).
But the Shi’a Imam, by being the current leader of the ummah possessed with Godly/Prophetic guidance to lead and arbitrate doctrine, in a sense becomes the physical substitute for the Prophet (PBUH) in our own day. That way there is always someone with prophetic guidance/divine inspiration to lead the ummah, even though Muhammad (PBUH) was the last prophet. The Shi’a Imam effectively becomes the unofficial prophet of his time, though the Shi’a will never admit to this fact and always seek to downplay it.
It is exactly like the doctrine of the Catholic Church, with the inspiration of the Holy Spirit being passed on from Jesus (PBUH) to the Apostles down the line of papal successors, so that Apostolic Tradition becomes a living one as embodied in the current pope.
In much the same way, for Shi’as a ruling by a current ayatollah or a book written by him is as equally authoritative for determining doctrine as are the Prophet’s Hadiths, though they will stop short of putting them on par with the Qur’an.
Do they believe this about all the Imams or just Ali?
All of them. It passed from the Prophet (PBUH) to Ali to his sons, and so on.
Also, how do Sunnis view the Shia Imams? Do they think highly of them, that they were righteous men, and good Islamic scholars?
In general, they are accepted as fellow Muslims and respected as scholars, especially Ja’far Al-Sadiq, who founded the Ja’fari school of jurisprudence, and to a lesser extent Musa Al-Kazim, though of course all their imamate-related roles are rejected.
Do they believe that any taught false doctrines? If so, which ones?
Anything imamate-related that may have been taught by them would have been considered false by Sunnis, but that’s not justification for thowing out the baby with the bath water, so to speak.
Is their a particular Shia Imam that Sunnis regard as especially teaching false doctrines?
Not that I know of, but I could be wrong.