Nature of oral tradition
Oral tradition has been defined as a testimony transmitted orally from one generation to another. Its special characteristics are the fact that it is oral and its manner of transmission, in which it differs from written sources. The oral tradition is complicated andi t is noteasytofindadefinition whichcovers all its aspects. A written record is an object: a manuscript, a tile, a tablet. But a verbal record can be defined in several ways, because a speaker can interrupt his testimony, correct himself, start again, and so on. A rather arbitrary definition of a testimony might therefore be: all the statements made by one person about a single sequence of past events, provided that the person had not acquired new information between the various statements. In that case, the transmission would be contaminated and we should be faced with a new tradition. Some people, in particular specialists like the griots, are familiar with traditions concerning a whole series of different events. Cases have been known of a person reciting two different traditions to account for the same historical process. Rwandan informants related two versions o f a tradition about the Tutsi and the Hutu, one according to which the first Tutsi had fallen from Heaven and had met the Hutu on earth, and the second according to which Tutsi and Hutu were brothers. Two completely different traditions, the same informants and the same subject! That is why the phrase 'a single sequence of events' has been included in the definition of a testimony. Lastly, everyone knows the case of the local informant who tells a composite story, based on the different traditions he knows.
A tradition is a message transmitted from one generation to the next. B u t all verbal information is not tradition. The eye-witness's verbal testimony mustfirstbe singled out. This is of great value because it is an immediate source, not a transmitted one, so that the risks of distorting the content are minimal. Any valid oral tradition should in fact be based on an eye-witness account. Rumour must be excluded, because although it certainly transmits a message, it depends b y definition on hearsay. Hence its grapevine character. It becomes so distorted that it can be of value only as expressing apopular reaction to a given event. That too can give rise to a tradition when it is repeated by later generations. Finally there is the true tradition, which transmits evidence to future generations.
The origin of traditions may therefore lie in eye-witness testimony, in a rumour or in a new creation based on different existing oral texts combined and adapted to create a new message. But only the traditions based on eye- witness accounts are really valid. The historians of Islam understood that very well. They developed a complicated technique to determine the value of the different Hadiths, or traditions purporting to be the words of the Prophet as recorded by his companions. With time, the number oí Hadiths became very large andit wasnecessary to eliminate those for which the chain of informants (Isnad) linking the scholar who had recorded them in writing to one of the Prophet's companions could not be traced. For each link the Islamic chronicler worked out criteria of probability and credibility identical with those employed in present-day historical criticism. Could the intermediate witness know the tradition? Could he understand it? Was it in his interest to distort it? Could he have transmitted it and if so when, how and where?

I never really thought about how Islam is based on oral tradition.