The Mishna brings cases comparing situations where an animal and a person may do the same damage but one would be obligated to pay damages and the other would not. If a person burns a field on Shabbat the person is exempt from payment of damages as when one does an action punishable by death, one is exempt from monetary payment. This Mishna raises a question against Rabbi Yochanan's view that one who burns as a destructive act has not desecrated Shabbat since one is only liable for creative acts performed on Shabbat. Two alternative readings of the Mishna are brought to answer this question. If an ox was chasing another ox and one ox was injured but there are different claims made by each of the owners about whether the damage was caused by the animal or by a rock, or if there were three animals and each owner claims the other's ox caused the damage, or the owner has two oxen, one large and one small or one tam and one muad, and each owner claims it was a different ox that caused the damage, the burden of proof lies with the one trying to claim the money from the other. Rabbi Chiya bar Abba holds that Sumchus would disagree in these cases and say that the money in question is split between the two sides. The Gemara tries to assess whether the case is where each is confident in their claim (bari) or one is confident and the other is not (shema).