Q: Two people in a house got into a heated argument, and one walked away with a broken arm. What evidence must he bring to sue the other person?

A: Generally, we require the explicit testimony of two valid witnesses to collect payment and do not rely on circumstantial evidence. However, in injury cases, if there were witnesses that someone entered the house intact and exited injured, the Sages relied on the circumstantial evidence to allow the victim to swear that the other person injured him and collect (C.M. 90:16).

If the wound was such that cannot be self-inflicted, e.g. between the shoulders, this is considered definitive knowledge, equivalent to explicit testimony – and the victim collects without an oath. If a third person was in the house, but he could not have inflicted the injury – it is considered as if just the two people were present (see Pischei Teshuva 90:1; Aruch Hashulchan 30:17).

Although women and relatives are generally disqualified from testimony, the Rishonim instituted that in places where valid witnesses are usually not available, e.g. the women’s section or at sudden brawls, we can rely on them in certain instances (Rama 35:14; Aruch Hashulchan 35:13).