Meilah, Chapter 4, Mishnah 4. This chapter continues to examine when separate items may be joined together to reach a halachic measure, whether for a prohibition or for the transmission of tumah. Our mishnah presents three cases: pigul together with notar, a sheretz together with a neveilah, and food that became tameh from two different levels of impurity.
The decree that pigul and notar render the hands tameh
Chachamim established that one who touches pigul (meat of a korban that was disqualified by an improper thought at the time of the service) has his hands rendered tameh, and whatever those hands then touch becomes tameh as well. This is entirely a rabbinic institution. On the level of Torah law there is no such category as hands alone becoming tameh while the rest of the body remains tahor; impurity of that kind takes hold of the whole person.
Why did Chachamim introduce it? Because a kohen who bore a grudge against a particular person could ruin that person's korban simply by thinking the wrong thought during the service. To keep the kohanim careful and to give them a personal stake in guarding their intentions, the Sages attached this consequence to contact with pigul. A parallel decree was made regarding notar, meat of a korban left over past the time in which it must be eaten, so that the kohanim would be motivated to finish the meat within its proper time and not leave any of it behind.
The practical result of both decrees is the same: once the hands have touched pigul or notar and have become tameh, if those hands then come into contact with terumah or with kodashim, the terumah or the kodashim become tameh.
Two names do not join together
The question of our mishnah is whether these two can be combined. The mishnah rules: "Hapigul vehanotar ein mitztarfin zeh im zeh mipnei shehen shenei shemot," pigul and notar do not join with one another, because they are two distinct categories. They are separate prohibitions with separate identities, and therefore a small quantity of one cannot be added to a small quantity of the other to reach the measure that conveys tumah to the hands, whether that measure is a kezayit or a kabeitzah.
The underlying principle is: "ein gozrin gezerot ligezerot," we do not issue a decree in order to protect another decree. The impurity of the hands is itself only rabbinic. To then say that two different Torah prohibitions combine with each other so as to activate a rabbinic impurity would be building a second layer upon the first, and Chachamim did not extend their enactments that far. There are rare instances in which the Sages issued two decrees at once and treated them as a single enactment, so that the second is not considered a decree upon a decree. Here, however, that is not the case: the Torah prohibitions of pigul and of notar are independent of each other, and the decrees issued about each of them are likewise independent. They therefore remain separate and do not merge to transmit tumah.
Creeping creatures, carcasses and corpse flesh
A piece of neveilah conveys tumah when it is the volume of a kezayit. The eight sheratzim listed in the Torah, the small creeping creatures, convey tumah in a far smaller amount, the volume of a lentil. Our mishnah asks whether pieces smaller than these measures can be added together.
Here is the mishnah's language: "Hasheretz vehaneveilah, vechen haneveilah uvesar hamet, ein mitztarfin zeh im zeh letamei afilu kakal shebishteihen." A sheretz paired with a neveilah, and likewise a neveilah paired with meat taken from a dead body, are not added to one another in order to transmit impurity, and this holds true even with respect to whichever of the two measures is the easier one.
Consider the opening pair. Before us is a fragment of sheretz that falls short of a lentil's volume, alongside a portion of carcass that does not amount to a kezayit. The two are not summed up even toward the kezayit, the more forgiving of the two amounts and the one demanded for a carcass; needless to say, they are not summed up toward the lentil, the tiny and more demanding amount that governs a sheretz.
In the second case, half a kezayit of neveilah does not join with half a kezayit of flesh from a human corpse. They do not combine to produce even the more lenient form of impurity, the tumah of a neveilah, from which one can become tahor at nightfall, and certainly not the more stringent form, the tumah of a corpse, which requires a seven day purification.
The levels of tumah
The mishnah's final case concerns tameh items that do combine, so we must first review the levels of impurity. At the top is the av hatumah, a primary source of tumah such as a sheretz or a neveilah, which is capable of conveying impurity to people, to utensils and to food. This impurity can then be passed along from object to object, but it weakens at every step.
- Whatever touches an av hatumah becomes a rishon letumah, a first degree of tumah.
- A rishon can convey tumah only to food and to liquid, not to people and not to utensils. The food or liquid it touches becomes a sheni letumah, a second degree.
- A sheni can convey tumah only to terumah and to kodashim, and those become a shelishi letumah, a third degree.
Food of the first degree together with food of the second degree
The concluding clause of the mishnah reads: "Ha'ochel shenitma be'av hatumah veshenitma bivlad hatumah mitztarfin zeh im zeh." One portion of food acquired its impurity by touching an av hatumah, so it stands as a rishon. A second portion acquired its impurity from a vlad hatumah, that is, from a rishon, so it stands as a sheni. Concerning this pair the mishnah rules that they are indeed reckoned together in order to pass impurity onward, and the level at which they do so, in the mishnah's words "kakal shebishteihem," is the lighter of the two.
Tameh food must be at least a kabeitzah in volume in order to convey tumah to other food, and here the two pieces do combine to reach that measure. Half an egg's volume of a rishon together with half an egg's volume of a sheni make up the required kabeitzah and can convey impurity.
But when they convey it, they do so only at the weaker level. The combination is treated as a sheni, notwithstanding the presence of the rishon within it, so that terumah which it touches becomes a shelishi. It does not act with the strength of a rishon, which would have rendered ordinary food a sheni; that power the mixture does not possess.