Bava Batra

Rabbah said: Behold, he is dead and his grave indeed proves this.  Abaye [however] said to him: [How] now! If [in the case of] a ship [that sank], where most of the passengers  are doomed to perish, [we] apply to the victims  the restrictions of living  men and the restrictions of dead  men, how much more [ought we to do] so  [in the case of] sick men, of whom most do recover. R. Huna, the son of R. Joshua. said: In accordance with whose [view] may that reported statement of Rabbah be justified?  In accordance with [the view of] R. Nathan. For it was taught:  Who takes away from whom?  He  takes away of their  possession without proof, but they [can] not take away of his possession except by [the production of] proof; these are the words of R. Jacob. R Nathan, [however]. said: If he  was in good health,  he must produce proof that [at the time the gift was made] he was lying sick;  if he was lying sick,  they  must produce proof that [at the time the gift was made], he was in good health. R. Eleazar said: As regards [Levitical] uncleanness also [they  differ in their views on the same principles]  as in [this] dispute. For we learnt: A [walled] valley in the summer [is subject to the laws of] a private domain in respect of the Sabbath  and [to those of] a public domain  in respect of [Levitical] uncleanness.  In the rainy season  it is regarded as a private domain  in both respects. Raba said: This  has reference only  [to the case] where a winter has not passed over it,  but [where] a winter has passed over it, [it is regarded as] a private domain in all respects. THE SAGES, HOWEVER, SAY: HE WHO CLAIMS FROM THE OTHER HAS TO PRODUCE THE PROOF.