Question
(1) As I mentioned, one of my specific interests is Tasawwuf and the Turug - both in Islam in general and in the Sudan in particular. In discussion with a Muslim professor from Tehran he said that Tasawwuf is really the heart of Islam and the message of God as revealed in the Koran and that it is Tasawwuf which explains the real meaning of Islam.
a) Do you feel that this is true or what do you feel is the relation between the teachings of the Sufi leaders of the past and the true Islam with regard to the ideas of Wusul and unity with God?
b) What good contributions and bad effects do you feel that the Sufi teachers have had on Islamic culture and Islamic History?
c) Now, regarding the Sudan in particular: Prof. Sanderson (at University of Khartoum ) has commented that Tasawwuf is one of the important bases of Sudanese culture. What valuable contributions, if any, do you feel that Tasawwuf or the Turug have made to Sudanese culture and history? What bad effects do you feel that the Turug had in the Sudan?

Answer
(1) I am sure that the Muslim Professor from Tehran was right in saying that "Tasawwuf is really the heart of Islam and the message of God as revealed in the Koran and that it is Tasawwuf which explains the real meaning of Islam."
At the very beginning I should like to point out that there is a difference between Tasawwuf, as such, and the teachings of the Sufi leaders of the past; Tasawwuf is a later name for an earlier practice. It is agreement with reality. The criterion was set by the life of the Prophet. In his life he was trying to be true to himself, to his fellowmen, and to God. In the second century to his flight from Mecca to Medina, the example of his life was been sought and followed by certain devotees. Asceticism, in one measure or another, was invariably among their qualities. It stood them apart from the rest of the people. It is then that the name of Sufia (plural of Sufi) came into popular usage. A Sufi, is a man who tries to imitate the Prophet's way of life, namely, who tries to be true to himself, to his fellowmen and to God, inasmuch as the Prophet was such. As time passed, the imitation, through ignorance, became more concerned with the letter than the spirit; and we invariably have the pseudo-Sufi.
The teachings of the Sufi leaders of the past, on the other hand, represent, at best, the individual attainments by those men of the example set by the Prophet. This difference between Tasawwuf and the teachings of the Sufi leaders of the past is important. It is with this difference in view that I agree with the Professor from Tehran in his statement about Tasawwuf.
Tasawwuf in this case is tantamount to the Prophet's practice. In other words, it is the Prophet alone who can be considered as an exponent of true Islam. This is not to belittle the excellent efforts of the Sufia.
a & b) The Sufi leaders of the past, in general, made contributions to Islamic culture that are equalled by none, in depth of thought and richness of quality.
Ibn Arabi and men of his caliber, passed through profound spiritual developments. They tried in their writings to convey to us experiences that belong to the greatest heights and depths that the spirit of man has yet reached - for all I know. Their revelations, expressed in words, are up to now unintelligible to most learnt men, yet their force of argument is irresistible. They ignited the ambition of lesser men to follow their example - men who would, otherwise, have thought that the example of the Prophet was beyond them.
The good contribution was not without bad effects. The bad effects were due partly to the utterings of the freakish and the immature (and there were plenty of them), and partly to the pseudo-Sufia. The shortcoming of the contemporaries of the great Sufi leaders to understand their teachings contributed its share to the bad effects. They were misunderstood, misquoted and grossly misrepresented. Many of the greatest of them all were killed on religious pretences. The mere fact of their having been killed greatly contributed to their bad effect on Islamic history. The day is dawning when justice will be done to the lives and memories of those great men.
I will come back later to say a word about the part of your question which touches on the idea of Wusul and unity with God; but then it will be in respect of Tasawwuf itself and not what the various Sufi leaders said about it.
c) Professor Sanderson is also right in his comment about the Turug in the Sudan. He probably understated their case. The Turug in the Sudan are responsible for the introduction of Islam itself to the Sudan.
The Gadria Tariga - the teachings of Sheikh Abdel Gader El Gailani of Baghdad - played the major role.
The men who were brought up in the ways of the Turug, by their sheer example, were able to keep the uneducated people of the Sudan in the religious fold. Some of these men were illiterate. By their modesty, simplicity, sincerity and truthfullness in regarding their religious rites, they attained such heights of wisdom that commanded the respect and love of a nation of illiterates to religion itself.
There are bad effects of course, but they are due to the pseudo-Sufia, as I mentioned before.