Sanhedrin

The text [above states]: 'R. Abbahu says all agree that a judgment given by two in monetary cases is not valid.' R. Abba objected and asked R. Abbahu [from the following]: If one has judged a case by himself and pronounced the guilty 'guiltless' and the guiltless 'guilty', or the clean 'unclean' and the unclean 'clean', his act cannot be undone, but he has to pay indemnity from his own pocket?  — Here we are dealing with a case where the parties accepted the judge. If so, why make him pay indemnity? — Because they had said to him: We agree to abide by your award on condition that you give a decision in accordance with the Torah. R. Safra asked R. Abba: What did the judge overlook in giving this erroneous decision? Was it a law cited in the Mishnah? But did not R. Shesheth say in the name of R. Ashi: 'If one overlooks a law cited in the Mishnah, he may revoke his decision'? — Hence it must be he erred in deciding against common practice. How can we conceive that? R. Papa said: If, for example, two Tannaim or Amoraim opposed each other's views in a certain matter and it was not clear with whom the true decision lay, but the general trend of practice followed the opinion of one of them, and yet he decided according to the opinion of the other, that is termed 'an error of judgment against common practice'. Is it true to say that the point of difference [between Samuel and R. Abbahu] had been anticipated by Tannaim in the following controversy? Arbitration is by three, so says R. Meir. The Sages say that one is sufficient. Now the Schoolmen presumed that all agree that the force of arbitration is equal to that of legal decision; their point of difference would accordingly resolve itself into one holding that three are required for legal decision and the other holding that two are enough.— No, all [both R. Meir and the Sages] agree that legal decision is by three, and the point in which they differ is this: One [R. Meir] holds that the force of arbitration should be regarded as equal to that of legal decision, while the other disputes it. May it be assumed then that there are three views held by the Tannaim with regard to arbitration, viz., one [R. Meir] holds that three are needed; another [R. Simeon b. Gamaliel] holds that two are sufficient,  while the Sages hold that one is enough? — R. Aha the son of R. Ika, or according to others R. Yemar b. Salomi, said: The Tanna who says two are necessary is really of the opinion that a single one is sufficient. And the reason he requires two is that they might act as witnesses in the case, if required. R. Ashi said: We may infer from this that no Kinyan  is needed for arbitration, for if it be thought necessary, why does the Tanna in question require three? Surely two should suffice, the two parties being bound by Kinyan!  The adopted law however, is that arbitration requires Kinyan [even when made by three]. Our Rabbis taught: Just as for legal judgment three are required, so are three required for settlement by arbitration. After a case has been decided by legal judgment, thou must not attempt a settlement.