Taharos, Chapter 7, Mishnah 1. The sixth chapter was devoted to the domains, the reshuyos, and how doubts about tumah are resolved in each one. With this chapter the Mishnah turns to a subject it has touched on more than once and now examines in depth: the am ha'aretz, the person who is not careful about the laws of tumah and taharah. How much do we suspect him, and how far do we go in guarding our own purity from him?
The framework was already laid down earlier: amei ha'aretz stand in relation to those who eat their ordinary food in purity as those people stand in relation to those who eat terumah, and so on up the ladder. Each level treats the level beneath it as a source of concern. Now the Mishnah brings that abstraction down to the street.
The potter who stepped away
"Hakadar shehinicha es kedeirosav veyarad lishtos." A potter has set out his pots and turns aside for a moment to go down and take a drink. He is a craftsman selling his wares, so his merchandise is spread out in a public place, and that public place is presumably full of amei ha'aretz. The concern is real, because an am ha'aretz carries midras impurity: his garments brush against an object and render it impure. So what is the status of the pots when he returns?
"Hapenimiyos tehoros vehachitzoniyos teme'os." The pots are lined up in rows, one behind the other, something like bowling pins. Those standing on the inside remain pure, while those on the outer edge are impure. The reason is straightforward: the outer ones are exposed, and it is likely that a passerby's clothing rubbed against them, while the inner ones are shielded by the outer rows.
Rabbi Yose's limitation
Rabbi Yose attaches a qualification, opening with the Mishnah's familiar formula, "bameh devarim amurim," under what circumstances was this taught? His answer: "bimfuzaros, aval ba'agudos hakol tahor." The ruling that the outermost pots become impure applies only where each vessel stands separately, scattered and unconnected, like those free-standing pins. Where the pots have been tied together into bundles, none of them contracts impurity at all. Imagine the bicycles parked outside a shop, all threaded onto one chain so that they form a single mass; pots too can be roped together that way, and in that arrangement, Rabbi Yose holds, taharah is preserved throughout.
Why exactly should being bundled make the difference? That itself is a matter of dispute. The Bartenura explains that because they are fastened to one another they do not shift when someone presses against them, and without that movement the midras impurity does not take hold, so the entire set remains pure.
The halachah, however, does not follow Rabbi Yose. We rule like the chachamim, the anonymous first opinion of the mishnah: the outer pots are impure whether or not they are bundled.
Handing over the key
The Mishnah ends with an entirely different scenario. "Hamoseir mafte'acho le'am ha'aretz." Someone entrusts an am ha'aretz with the key to his home. The likely picture is a neighbor: the owner fears being locked out one day, so he leaves a spare next door. From that moment the neighbor holds the means to walk in whenever he pleases. Must we now treat the contents of the house as questionable?
"Habayis tahor." Everything in the house retains its taharah, and the Mishnah explains why: "shelo masar lo ela shemiras hamafte'ach." The neighbor was made a guardian of a piece of metal, nothing more; entry into the home was never part of the arrangement. No permission to come inside was extended to him, and he would not presume to use the key on his own, since anyone who did so would be behaving like a burglar. Consider how such things work between people: when you leave a spare key next door, you certainly do not imagine your neighbor strolling from room to room in your absence. Such conduct would be altogether bizarre.
And it is precisely on that ordinary human expectation that the halachah rests. Even an am ha'aretz, whom we do not trust in matters of tumah and taharah, is presumed not to help himself to a house that was never opened to him. He was entrusted with a key, and a key is all he received.