My gut reaction is that this is extremely false.
Funny, my gut reaction is that this is extremely true.
If 1 or a million people tell me some thing, there are exactly 3 options available to me:
Suppose my 50 neighbors - all nice normal folks - tell me in passing that they saw my brown dog loose in the morning. Why would I decrease my belief? Wouldn't that be incredibly perverse?
And why would I ignore them and leave my belief unchanged? I don't discriminate against any other information source. If my eyes tell me 50 times that my brown dog is loose, I don't go 'phsaw, who cares what you guys think'. I increase my belief that my dog is loose.
About any proposition in general, the more people tell you it, the more you believe it. Let's generalize this even more: the more data you have telling you to believe some proposition, the more you believe that proposition. (What a shocking conclusion.)
Now, sometimes there are conspiracies, but they are extremely rare and unlikely and require involved explanations (like explaining the existence of religious belief in general does). Those Jews are right that the more testimony the greater the likelihood, but this truth does not prove the things they want it to prove.
tl;dr: your post is ill-founded and you need to explain why the Bayesian solution to the raven paradox is wrong.
About any proposition in general, the more people tell you it, the more you believe it.
Which is very poor practice if they were all convinced by each other.
Something I've been hearing a lot lately (specifically from Orthodox Jews, although it comes up a lot in debates about religion) is that having a large number of people telling a story makes it more likely the story is true, because multiple witnesses can call each other out for deviating from the truth.
My gut reaction is that this is extremely false. But it's a point that should be scientifically testable, and I figure that someone should have done a study on it by now. Does anyone know of such a thing?
A related issue is the argument that oral tradition meant something very different thousands of years ago, when it was the ONLY form of historical record. Oral historians were duty-bound to preserve the story. This sounds plausible. It probably ISN'T as easily testable since we can't compare oral history from pre-writing times against... well, much of anything. (Well, I guess archaeological evidence, if the events being described would have left enough archaeological evidence). Is there an official, accepted scholarly opinion on this?