Kelim, Chapter Four, Mishnah One
In mishnah 2:2 we learned that a potsherd (broken piece of pottery) which can stand without support and can be used to contain a minimal amount of liquid is still susceptible to impurity. In today’s mishnah we learn that if it cannot stand without support than it is not susceptible.
1) A potsherd that cannot stand unsupported on account of its handle, or a potsherd whose bottom is pointed and that point causes it to overbalance, is clean.
2) If the handle was removed or the point was broken off it is still clean.
a) Rabbi Judah says that it is unclean.
3) If a jar was broken but is still capable of holding something in its sides, or if it was split into a kind of two troughs:
a) Rabbi Judah says it is clean
b) But the sages say it is unclean.
Section one: Since the broken piece of pottery cannot stand on its own, it is not considered a vessel and it is not susceptible to impurity.
Section two: According to the first opinion, once a broken piece of pottery becomes pure (because it cannot stand on its own) it can never go back to becoming susceptible to impurity. This serves to distinguish a broken piece from a whole vessel, because if whole vessels are repaired they can again become susceptible to impurity.
Rabbi Judah disagrees, holding that broken pieces are just like whole vessels. Once repaired such that they can hold a minimal amount of liquid, they again become susceptible to impurity.
Section three: The jar was broken such that it can still hold liquids when stood on its side. Alternatively, it was split into two pieces, both of which can hold some liquid when stood on their side.
In this case, Rabbi Judah rules leniently. According to Rabbi Judah a potsherd can retain its susceptibility to impurity only if it can contain liquids in the same way that the original vessel did. Since these potsherds receive liquids only when standing on their sides and not when standing upright, they are pure.
The other sages disagree and hold that as long as it can hold liquids, the potsherd is still susceptible to impurity.
Note that the mishnah seems to want to balance a lenient ruling of Rabbi Judah with a stringent one, and so too when it comes to the sages. This could either be an easier way of remembering things, or perhaps a way of telling the reader that rabbis cannot necessarily be classified as either stringent or lenient on these matters. Rather they differ based on principles, and those principles sometimes lead them in differing directions.