Eduyos Chapter 3, Mishnah 1. In this chapter we begin a series of mishnayos dealing with the disputes between Rabbi Dosa ben Harkinas and the Sages. Rabbi Dosa ben Harkinas was one of the elders of the generation in the time of Rabbi Akiva, a man of great stature, and these are the opinions of his that the Sages disagree with. The first mishnah deals with the way tumah is transmitted, and its parallel is found in chapter 3 of Maseches Ohalos. Since the material is built in layers, let us first lay out the background for each one.
The three ways a corpse conveys tumah:
Touch - direct contact with the source of tumah.
Carrying - bearing the weight of the source of tumah, even without touching it, such as carrying it in a bag or on a bed.
Ohel (tent) - and this has three forms: the one receiving the tumah (a person or a vessel) is under one roof together with the tumah; the one receiving the tumah overshadows the tumah, such as someone stepping over a corpse lying on the ground; or the tumah overshadows him, when it is carried over his head.
It is worth noting that not only a whole corpse conveys tumah, but even a significant portion of it. Maseches Ohalos discusses this at length and specifies various measures: an olive's volume of flesh, a quarter-kav of bones (as we have already seen earlier in this maseches), and other measures for decayed matter, blood and the like. For our purposes we will be dealing with flesh, whose measure for transmitting tumah is an olive's volume.
The question of the mishnah: two half-olive pieces:
What is the law when the olive's volume is not one whole piece, but two small pieces that together add up to an olive's volume? Do they convey tumah or not?
Rabbi Dosa ben Harkinas: They do not combine. As long as he does not have a single whole piece of the required measure, the tumah does not have enough force to be transmitted, and that is all.
The Sages: They do combine and convey tumah, provided that the manner of transmission of both halves is the same: both by touch (the right hand touching one half and the left hand the other half), or both by carrying, or both by ohel.
It also emerges from the mishnah that ohel is in a certain sense similar to touch: the ohel makes it as though the corpse fills the entire space, so that whoever is inside it is considered as having come into contact with the corpse. For this reason, according to the Sages, half an olive's volume by touch combines with half an olive's volume by ohel, while Rabbi Dosa ben Harkinas says that they never combine.
Two types of ohel:
An ordinary ohel: a roof shared by the tumah and by those who receive it. Everything in the house becomes tamei: the people and the vessels become primary sources of tumah, and foods and liquids likewise become tamei.
Tumah retzutzah (crushed tumah): the source of tumah is pressed and squeezed in, meaning that there is no handbreadth (the width of a hand, four fingers) of space around it in every direction, such as a corpse lying flush against the ceiling. In such a case the ohel does not serve as a barrier and the tumah does not spread to the sides, but rather breaks through and rises up to the heavens and descends down to the depths.
From here comes a secondary dispute that is also included in our mishnah: tumah retzutzah is the more compressed and more powerful version of ohel. Some hold that only it is considered like touch, while an ordinary ohel, in which there is space around the tumah, is not like touch. Others hold that every ohel, whether crushed or not crushed, has the status of direct contact.
The wording of the mishnah:
"Kol hametamei b'ohel" - anything that transmits tumah by way of an ohel (overshadowing). It should be stressed that the only thing that transmits tumah through an ohel is the remains of a human body and nothing else, though it is enough that it be a significant portion of the body. "Shenechlak" - and it was split into two halves, so that there is no single intact piece of the required measure, and each limb has its own measure according to its law. "V'hichniso l'toch habayis" - he brought both halves under one shared roof, beneath which a person or a vessel is located. "Rabbi Dosa ben Harkinas metaher" - the two halves do not join together into a whole, and even an ohel does not help in this regard. "Vachachamim metam'in" - they do join together, and everything under the roof is tamei.
"Keitzad" - the six cases:
Before listing the examples, an introduction is needed: in these six cases we are not dealing with an ordinary ohel, but with an ohel in a state of tumah retzutzah (crushed tumah), where there is not a handbreadth of space on any side of the tumah. This is the most forceful form of transmission, and it is the one analogous to direct contact. In all of these cases Rabbi Dosa ben Harkinas rules tahor and the Sages rule tamei, since the mode of transmission is identical for both halves.
Contact and contact - "Hanogea bishnei chatzayei zeisim min haneveilah": he touches half a kezayis with his right hand and half a kezayis with his left. According to this version, neveilah (the carcass of a dead animal) is included as well, and the same law applies to flesh from a corpse.
Carrying and carrying - "O nos'an": two half-kezayis pieces are placed in two vessels, without direct contact, and he bears the weight of both at once, one in his right hand and one in his left.
Contact and ohel: his right hand touches half a kezayis, and his left overshadows a second half-kezayis lying in a crushed space.
Contact and ohel: his right hand touches half a kezayis, and the second half-kezayis overshadows his left hand, in a crushed space.
Ohel and ohel: both his hands overshadow two half-kezayis pieces lying in a crushed space.
Ohel and ohel: his right hand overshadows half a kezayis, and his left is placed beneath a half-kezayis that overshadows it. In a combination of ohel with ohel there is no longer any need for a crushed space, since here there is no comparison being drawn between ohel and contact.
The two reverse cases:
In contrast to these, the Mishnah brings two cases in which there is no combining: his right hand touches half a kezayis of flesh and his left is under one ohel with half a kezayis of flesh, except that this is not crushed tumah but an ordinary ohel; or his right hand overshadows half a kezayis in a crushed space, while another half-kezayis overshadows it not in a crushed space. The novelty is that even when both hands receive by way of ohel, as long as one of them is in an ohel that spreads out to the sides and the other is in tumah that breaks through and rises upward, these are two different modes of transmission. The first is considered like direct contact and the second is not, and therefore all agree that in this case it is tahor, and even the Sages do not combine them.
The view of Rabbi Meir:
Rabbi Meir says: "Af bazeh Rabbi Dosa metaher vachachamim metam'in". In his view, the Sages draw no distinction whatsoever between crushed tumah and tumah that is not crushed: an ohel is an ohel, and both forms are essentially equivalent to contact. Therefore, if one half comes by way of an ohel of any sort and the other half by way of contact, they join together and transmit tumah. Rabbi Dosa ben Harkinas, as is his way, says that two halves never join together at all.
Rabbi Meir goes on to explain Rabbi Dosa's approach: "Hakol tamei chutz min hamaga im hamasa" - that is, half a kezayis that comes by way of carrying together with half a kezayis that comes by direct contact, "v'chein hamasa im ha'ohel" - half a kezayis that is carried together with half a kezayis in an ohel, do not join together. In other words: contact and ohel are one pair, an identical mode of transmission, and therefore they combine; carrying, however, combines neither with contact nor with ohel.
The principle that emerges from the Mishnah:
The Mishnah sums up: "V'zeh haklal: kol shehu misheim echad - tamei, mishnei sheimos - tahor". If the mode of transmission of the two halves is identical, they combine and it is tamei; and if they are two different modes, there is no combining and it is tahor. Conceptually, this principle is accepted by both Rabbi Meir and the first tanna, while Rabbi Dosa ben Harkinas says that there is no combining here at all, since two halves never join together to transmit tumah.
The halachah: The ruling follows the first tanna, in accordance with the Sages. That is, we do combine two half-kezayis pieces; and we distinguish between crushed tumah and ordinary tumah: crushed tumah has the status of contact, whereas an ordinary ohel that is not crushed does not.