There is an argument between the Ri of Gash and the Rambam. [Laws of Testimony 21:6] [ sys The Ri Mi'Gash (Rav Joseph of Gash) was the teacher of the father of the Rambam.] Three brothers testify for three years of "hazaka". The Mishna itself says that is valid if each brother testified for one year and another person testified with him. But if there are other witnesses that come and say how can you say that when you were with us the whole time. To the Ri Migash there is no payment to the owner since brothers can not testify together. The Rambam says there is payment. The question is how to explain the Ri Migash that even the Ramban [Nahmandes asks on]. Rav Shach explains this in Laws of Testimony. But I have to write his answer at a different time because of a certain amount of chaos that is in my life this minute.
OK. [My life is always in chaos, but Thanks to Heaven that I have a few minutes now to write the answer of Rav Shach and my slight question after that.] The answer of Rav Shach is that the Jerusalem Talmud says ומנין שלא יהיו עדים קרובים זה לזה? הגע עצמך אם הוזמו לא מפיהם הם נהרגים ("From where do you know that witnesses can not be relatives? Just think about it. Is it not so that if they would become false witnesses they would not be killed?") The Yerushalmi is thinking that no testimony can be valid unless there would be a punishment if it turned out to be false. עדות שאי אתה יכול להזימה. And the Rif brings that Yerushalmi.
I have no question that Rav Shach is correct that this Yerushalmi is the source of the Ri Migash. But the question remains how is it possible that any testimony can be accepted if not for the fact that if it would turn out to be false that there would be the same punishment that the false witnesses wanted to give to an innocent person? You still have the very same question that started the whole process.
