I have 2 questions to ask of you.
1. There are people who believe that Prophet Muhammad (PBUH) had knowledge of the unseen ('Ilm-e-Ghayb). They say that in addition to revelation (waḥī) Allah used to convey to him (PBUH) through Angel Gabriel (as) information of future for onward communication to people. They (people) claim that to be knowledge of the unseen ('Ilm-e-Ghayb).
2. These people also insist that one should pray to Allah in the name of pious religious scholars and the divine Messengers especially the Holy Prophet (sws).
Thanks for the mail. I have been assigned to respond to your questions regarding knowledge of the unseen and the intercession of mystics and the Messengers. My response is based on Mr Ghamidi's view on the issues.
1. We believe that the belief that the Prophet (sws) possessed any knowledge of the unseen is clearly negated by the Holy Qur'an, the basic source of religious knowledge. The argument you have referred to in this regard does not lead to the intended conclusion. All the Muslims believe that the God Almighty did interact with the Prophet (sws) besides divulgence of the Qur'an. All the Sunan (http://understanding-islam.org/related/text.asp?type=question&qid=322&sscatid=387) instituted by the Prophet (sws) and the process involved in the preaching mission divinely ordained and were communicated to him by God. The view that the Prophet (sws) was not contracted by God in other than the Qur'an and that he could not tell anything outside the Qur'an or institute a binding practice is clearly blasphemous. However, to tell someone having known it from any external source and possessing knowledge of the unseen are two different things. If I am told by someone else that a certain person is going to do such and such thing on a given time in future, and the source is absolutely reliable then my knowledge of the fact does not mean I have the knowledge of the unseen. If we are sure that the Prophet prophesies such and such happening through a source which is not subject to criticism, we have to believe in his information. The problem however, is with the authenticity of the claims in this regard. It was not normal practice of the Prophets of God to explicitly mention some future event even if they were intimated by God about that. This is precisely for this reason that we find that the scholars of the science of hadith employed the principle that anything ascribed to the Prophet (sws) which clearly identifies a future event or praises an individual by name has to be considered worthless.
This is because they were all alive to the fact that it was not the practice of the Prophet (sws) to throw prophesies like that.
The Holy Qur'an has negated the idea that the Prophet (sws) did have any such ability. It frequently makes him respond to the opposition among the addressees that he did not know when will the divine punishment fall on them or when the last day is going to happen (67:25-6and 6:50)
2. I am sorry I could not fully understand your question in this regard. If it implies that we should put these personalities as interceders and then ask God for help then we are doing something which is totally alien to Islamic teachings. Prayer is a direct communication of a servant of God to Him. The Almighty says that we need to turn to Him directly, putting all trust in Him and He will listen to our prayers if they are in accordance to His profound wisdom. Sometime He may not accept our prayer for it goes again His wise plan yet it does not go in waste. He will reward us for turning to Him for help.
If however, the question implies that God has given these personalities to such an extent that they can affect God's decision it would be outright negation of power and sovereignty of Almighty. He has not given any such power. The Holy Qur'an clearly negates the idea that the dead has any connection with the world behind us. Therefore, belief that these personalities work as active agents implies negation of the basic teachings of Islam and in most cases amounts to polytheism (you may also refer to the following discussion on a similar topic: http://understanding-islam.org/related/text.asp?type=question&qid=2269 )
I hope this answers your question. If however, anything remains unanswered or you need further discussion please feel free to write back.