Shevuot 46: Who Must Swear, The Need for Proof

If a worker claims to have been hired for two zuz but the employer says that the was employed for one zuz, who must swear?  The rabbis suggest different solutions.  Does the employer swear because most people remember getting paid?  Is a proof required?  If the employer faces no evidence condemning him, does he swear and then is he believed?  

What if one gives his garment to a craftsman to be fixed, and they argue about whether one or two garments were to be returned.  If the garment has not been returned within the quoted 'ready' time, then it is permitted to go along with the worker's request.  But if the garment is late, he is to be given two garments.

The rabbis debate why the employer, worker, or others should swear and then collect.  Rav Nachman bar Yitzchak suggests that we learn this through Rabbi Yehuda.  He was quoted in a baraita saying that whenever the Torah tells the employer to swear, the Sages decided that the worker should swear and collect.  Or perhaps this is when the employer claims partial responsibility.  If the employer denies all responsibility (ex., I never hired him at all), the worker must bring proof of having been hired.  The rabbis also argue about who wrote which baraitas.  

Comparing different cases, the rabbis examine the notion of "proof", threats, and the trustworthiness of the person who might be asked to swear.  What is most interesting to me here is that the rabbis consistently consider the context of the potential crime.  The rabbis are aware of human nature - the possibility that people might say things that are exaggerated and should not be taken as absolute predictors of behaviour.  

A number of people are disqualified from swearing.  For example, one who has wounds on his back is not suspected of creating those him/herself.  If a person has been wounded, s/he need only swear about those wounds he might have done to himself.  The rabbis argue about whether or not a vain or false oath leads to swearing automatically.  One might not have intended to lie falsely, it is explained.