By Ari Shapiro
What exactly are the eidim saying?
The Rambam in the Peirush Hamishnayos explains that 2 witnesses come and testify that they saw the 2 of them lift up the object together. The problem with the Rambam is what is the chidush? We always believe 2 eidim.
R' Akiva Eiger on Mishnayos offers a different pshat. He says that if you hold that 1 witness can exempt you from an oath then the case here is that each person has 1 witness testifying that they picked it up alone. The problem with this is that since the witnesses contradict each other we should just throw them out.
The Rashash offers a similar pshat. He says each one has 2 witnesses testifying that they picked it up alone. He asks, but when 2 sets of witnesses contradict each other we throw them out so we should be back to square one and they should need to swear? He answers that since the shevua is only a takana d'rabbanan, in this case the chachamim were not mesaken a shevua.