Edim Zomemim - Why Not Believe Them?

Question

There is a concept of Edim Zomemim (Wikipedia has it translated as "Collusive Witnesses") (עדים זוממים).

Basically, if two witnesses testify about someone, and then two other witnesses come and say something along the lines of "you cannot be true, because you weren't there," we believe the latter pair, and punish the former.

My question is why do we believe the second over the first? What makes them any more believable? Maybe they're also lying.

[I understand that this is what the Torah says we do. I'm just looking for a logical explanation]

Answer 1

Rambam (Mishna Torah, Hil. Edim 18:3) notes that this rule is a g'zeiras hakasuv and gives no reason.

According to Ramban (Devarim 19:18)(as expounded upon by Ralbag and Abarbanel), the logic is as follows: When we have two pairs of witnesses in contradiction (i.e. "Reuven did X" vs. "Reuven did not do X") then we have no reason to believe one pair over another and may not take any form of action. However, here, Pair A of witnesses say "Reuven did X". The fact that they were present at a certain place at a certain time is not technically part of their testimony; it is just necessary background information. Thus, Pair B of witnesses, when they say that Pair A were in fact somewhere else at that time, they render Pair A's testimony impossible, and yet they have nobody technically contradicting them, since to do so there would need to be witnesses that Pair A were indeed at the relevant place at that time. (And Pair A themselves cannot testify concerning themselves.)

Ran in his d'rashos (11) gives another reason: We believe the witnesses who have less ability to lie. The first witnesses can set up a story and create false testimony and perhaps they were confident that nobody saw them elsewhere at the time they specify in their testimony. But if it is Pair B that is indeed lying, how are they not worried to testify falsely when Pair A knows that they are lying? All Pair A would have to do is bring other witnesses that they know were at the scene of the crime as well and saw them there. Thus, it is more likely that Pair A are the false witnesses since they have more "ease" in lying.

Answer 2

Their are different explanations given. Some give the technical reason that the zomemin are being testified against directly, while their testimony is on some other matter. The 2nd group's testimony falls directly on the 1st group, and they can't defend themselves from a an edus against them. (Compare this with regular contradicting testimonies, where both are rejected.)

Another reason given is the ease of testimony, though its not as clear-cut. Its easier for the first group to lie, since they can plan what time they will say they saw something. On the other hand, the second group will have to mention the same time as the first group, which is more difficult to plan in advance. (If they're lying, other people may have seen them..)

Answer 3

I'm not all that knowledgeable on the subject, but I would assume that V'Darashta V'chakarta... also applies to the second pair of witnesses. After all, it's impossible to know right off the bat that the second pair is not trying to lie to help a friend of there.