And why do we mention the words of Shammai and Hillel for naught? In order to teach future generations that a person should not stand by his opinion, for even the patriarchs of the world did not stand by their words.

And why do we mention the opinions of an individual among the majority since [in any case] the halachah does not accord [with him] but rather with the opinion of the majority? So that if a court will form the opinion of the individual and rely upon him, then a subsequent court will not be able to nullify the verdict of its fellow court unless it is greater than [the first court] in wisdom and in number. If [the latter] was greater than [the former] in wisdom but not in number, or in number but not in wisdom, it is not able to nullify the decision of the [former court] unless [the latter] is greater in number and in wisdom.

R' Yehudah said: If so, why do we mention the opinions of an individual among the majority for naught? So that if a person will say, “Thus have I received as a tradition,” one will [be able to] answer him, “It is in accordance with the words of So-and-so that you have heard!”

Beis Shammai say: A quarter[-kav] of bones [transmits tumah] from the bones, whether from two or three. But Beis Hillel say: A quarter[-kav] of bones [transmits tumah only when they come] from the [bones of a single] corpse, from a majority of the structure or from a numerical majority. Shammai says: Even from one bone.