130 Eduyot 6/2-3

(2) Rabbi Yehoshua and Rabbi Nechunya the son of Elinatan, the leader of Kfar Babylon, testified about the limb of a dead person that it is impure [i.e. it imparts impurity to anything under the same roof-space]. Rabbi Eliezer says: They [i.e. the Sages] only said this about a limb taken from a live person. They said to him: Can we not make [a logical inference that supports our view based on what you said]? If a live person is ritually pure, yet the limb from him is impure, is it not [logical to conclude] that [when] a dead person, who is impure, loses a limb, [that limb is also] impure? He said to them: [True, but] they only said [their law] in reference to a limb taken from a live person. Another answer: [There are] more [ways to impart] impurity while alive than while dead, for a live person can make that on which he lies and sits impart impurity to man and clothes, and he renders what is over him a medium that imparts impurity to food and drink, which are not impurities that a corpse can cause. [Thus, the previous logical inference of Rabbi Yehoshua and Rabbi Nechunya does not necessarily stand.]

(3) An olive's size of flesh that separated from the limb of a living person: Rabbi Eliezer declares impure, and Rabbi Yehoshua and Rabbi Nechunya declare pure. A barley-grain's size of bone that separates from a limb of a living person: Rabbi Nechunya declares impure, and Rabbi Eliezer and Rabbi Yehoshua declare pure. They said to Rabbi Eliezer: Why did you see [fit] to declare an olive's worth of flesh that separated from the limb of a living person impure? He said to them: We find that the limb of a living person is like a complete dead person. Just like an olive's size of flesh that separates from a dead person is impure, so too an olive's size of flesh that separated from the limb of a living person is impure. They said to him: No. If you say that an olive's size of flesh that separated from a dead person is impure, as is a barley-grain's size of bone that separates from [a dead person], [how] will you also declare an olive's size of flesh that separated from the limb of a living person impure when you declare pure a barley-grain's size of bone that separates from [the limb of a living person]? [You yourself do not appear to judge these cases as parallel to each other, so how can you claim that to be your reasoning?] They said to Rabbi Nechunya: Why did you see fit to declare a barley-grain's size of bone that separated from the limb of a living person impure? He said to them: We find that the limb of a living person is like a complete dead person. Just like a barley-grain's worth of flesh that separates from a dead person is impure, so too a barley-grain's worth of bone that separated from the limb of a living person is impure. They said to him: No. If you say that a barley-grain's worth of bone that separated from a dead person is impure, as is an olive's size of flesh that separates from [a dead person], [how] will you also declare a barley-grain's size of bone that separated from the limb of a living person impure when you declare pure an olive's worth of flesh that separates from [a living person]? [You yourself do not appear to judge these cases as parallel to each other, so how can you claim that to be your reasoning?] They said to Rabbi Eliezer: Why did you see fit to divide your method [and be inconsistent in your reasoning]? Either they are both pure, or they are both impure! He said to them: [There are] more [chances for] flesh [to become] impure than [there are chances] for bones [to become] impure, for flesh applies to carcasses and insects, which is not so for bones. Another answer: A limb that has enough flesh on it [that were it still attached to a human being, it would be viable] imparts impurity by touching, carrying, and being under its [same] roof-space. If one diminishes the flesh [of the limb], it remains impure. If one diminishes the bone [of the limb], it [becomes] pure. They said to Rabbi Nechunya: Why did you see fit to divide your method [and be inconsistent in your reasoning]? Either they are both pure, or they are both impure! He said to them: [There are] more [chances for] bones [to become] impure than [there are chances] for flesh to become impure, for flesh separated from a living man is pure, but a limb that is separated from [a living man], and it is full [with flesh, bone, and sinews], it is impure. Another answer: An olive's worth of flesh [severed from a corpse] imparts impurity by touching, carrying, and being under its roof-space, and bones create a majority in making impure by touching, carrying, and being under its [same] roof-space, and a majority of a corpse's bones impart impurity by touching, carrying, and being under their [same] roof-space. If one diminishes [the] flesh [that has been severed from a corpse], it [becomes] pure. If one diminishes the majority of bone, even though they [now become] pure [and can no longer impart impurity on whatever is] under their same roof-space, they [still] impart impurity by touching and carrying. Another answer: Any flesh of a dead person which is less than an olive's worth is pure. But [bones that makes up] the majority of a dead person's build or [constitute] a majority of his [bone] count, even if they are only a quarter [kav (a measure)], they are impure. They said to Rabbi Yehoshua: Why did you see fit to declare both [bone and flesh from a dead person] pure? [Is not Rabbi Nechunya's reasoning correct?] He said to them: No. If you say about a corpse [that it is impure, it is because of] the laws of majority, quarter [kav], and decay [that apply to it], but [how can you] also say about a living person [that he is impure], [if] he does not have the laws of majority, quarter [kav], and decay [apply to him]? [You cannot compare that which was separated from a corpse with that which was separated from the limb of a living person, because the limbs severed from a living person are less likely to impart impurity than the corpse.]