Tawaatur
Tawaatur (تواتر) is supposed to be a concept that will solve the problem that the reports about Muhammad are based solely on oral traditions. Tawaatur means "succession" and in the "science" of hadiths it means that there is a lot of isnaads (chains of narrators of an oral tradition). When a hadith has a lot of chains, the hadith is then called "mutawaatir" (متواتر). The mutawaatir hadiths are distinguished from hadiths that are called ahaad (آحاد) which have a "small" number of chains (although ahad literally means "one" [1]).
The number of chains
The number of chains that a hadith needs to be mutawaatir is defined by scholars. However scholars don't know what the number of chains is:
There is no precise definition for a "large number of reporters"; although the numbers four, five, seven, ten, twelve, forty and seventy, among others, have all been variously suggested as a minimum, the exact number is irrelevant (some reporters, e.g. Imams of Hadith, carry more weight anyway than others who are their contemporaries): the important condition is that the possibility of coincidence or "organised falsehood" be obviously negligible.
The hadith is mutawaatir when there is "no possibility" that so many people could agree on a lie. So it's very subjective. Some scholar might think that 4 chains are enough, other might think that 70 chains are needed.
- There were thousands of Muslims available when the hadiths were written, so even if most Muslims were honest, it wouldn't be hard to find 4, 5 or 70+ liars.
False chains
When a hadith is mutawaatir it has to be accepted according to Islamic scholars:
With regard to the ruling on mutawaatir reports: a mutawaatir report must be accepted, because it is definitive and certain, even if there is no other corroborating evidence. And there is no need to examine the biographies of its narrators. This is a matter concerning which no wise man will have any doubts.
So a big number of chains means that the content of the hadith is 100% from Muhammad. But anyone can make a false chain of narrators for his made up hadith:
- If a person who writes the hadiths makes up his own hadith, he can include "many" (4, 5... or 70) made up chains and it will be called "mutawaatir"
- This shows that a hadith can be mutawaatir even though it has 0 authentic chains, not even partially authentic
- If "many" (4, 5... or 70) people who narrate the oral traditions to the person who writes the hadith make up false chains, the hadith will be called "mutawaatir"
- If "many" (4, 5... or 70) people who, narrated to the people who narrated to the person who will write the hadiths, made up false chains, the hadith will be called "mutawaatir"
- If "many" (4, 5... or 70) people heard an authentic report from Muhammad, but weren't sure what exactly he said and consulted each other and the most confident of them "assured" them that his version is correct (although it wasn't) and then they narrated it to the people etc.. it will be called "mutawaatir"
- If 70 honest people heard from other honest people who heard from other honest people.. an authentic report from Muhammad and then they narrated it to the person who will write the hadiths, but they knew only the names of the people who told them and didn't know the names of the people who told to the people who told them, then the hadith is unreliable.