At the opening to chapter 15 of Hilchot Tumat Met, the Raavad, one of the most frequent disputants to Maimonides’ Mishneh Torah, sets out a position that seems to be contrary to the position of Maimonides’. But are they really in disagreement?

The laws of ritual impurity imparted by a corpse are notoriously complex. For this discussion the following suffices: If a corpse is in a room with an opening to an adjoining room (we will discuss what size this needs to be below), then the impurity travels through the opening and transfers to the next room. Maimonides discusses what steps can be taken to block the opening and prevent the transfer:

The following laws apply when a functional window was closed entirely or closed to the extent that less than a handbreadth by a handbreadth remained. If it was closed with an entity that intervenes in the face of ritual impurity it is considered closed, provided it is an entity that the owner does not intend to move.1

The Raavad comments:

Less than a handbreadth with regard to less than an olive-sized portion of a corpse. However, with regard to more than that, it is sufficient for the opening to be less than four handbreadths by four handbreadths.

So in a case where more than an olive-sized portion of the body remains, all one has to do is make the opening less than four handbreadths by four handbreadths; there is no need to make it less than one handbreadth wide.

Rabbi Yosef Karo in his commentary to Maimonides, Kesef Mishnah,2 argues that the Raaved’s objection is not valid, because even though Maimonides did not spell out or even mention the distinction of an olive-sized piece vs more than that, this was in fact his intention. The reason it is not spelled out, continues the Kesef Mishnah, is because Maimonides is borrowing the language of the Mishnah on which the law is based. Since the Mishnah does not explicitly make the distinction, neither does Maimonides.

The Kesef Mishnah asserts that Maimonides is relying on his earlier articulation of this distinction, in chapter 7 of Hilchot Tumat Met where he writes:

How large is the measure of a doorway? If an entire corpse is in the building, the entrance must be four handbreadths. (Since the corpse must be able to leave through this opening) If there is only an olive-sized portion of a corpse, the entrance need only be a handbreadth wide. Any portion larger than an olive-sized portion is considered an entire corpse and requires an entrance of four handbreadths

Since this distinction was stated previously, Maimonides does not feel the need to repeat it. So in truth, when Maimonides refers (here, in chapter 15) to an opening that was closed to less than a handbreadth by a handbreadth, this would indeed only apply with regard to the transfer of impurity of an olive-sized portion of a corpse. If, however, an entire corpse was present, then we would only need to reduce the opening to less than four handbreadths by four handbreadths. This is due to the fact that impurity of a corpse is only imparted by an opening through which it would be possible to remove the corpse.

However, this explanation of the Kesef Mishnah seems to be a bit of a stretch. Firstly, would Maimonides really omit such a basic element? The difference between four handbreadths and one is quite stark! How could Maimonides suppose that his reader would extrapolate the correct meaning from an earlier chapter?3

Secondly,4 and more importantly, it seems that when Maimonides made the earlier distinction, he was referring to an entirely different case. Here he is referencing a case of transfer of impurity from one room to another, whereas earlier in chapter seven he is referring to a sealed building within which impurity is trapped:

When a corpse is located in a closed structure … it imparts impurity to all its surroundings. (Since the impurity cannot be removed.) Anyone who touches the back or the roof of the structure contracts the impurity that lasts seven days, because it is like a closed grave.5

If an entrance had been opened in it … one who touches the back of the structure or its roof, is pure. Only the area in front of the door is impure. (Since the impurity will be removed through this opening.)

In this scenario we are attempting to revoke the stringent status of a closed grave. This is where he makes the distinction (quoted above) regarding an entire corpse vs an olive-sized piece. For an entire corpse, you need four handbreadths by four handbreadths; it must be possible to remove the corpse through the opening.

Our case, however, is not discussing a closed structure. We are referring to a regular building with open doors; the question is simply what size window transfers impurity from one room to another. The answer to this is—as Maimonides explicitly states—one handbreadth by one handbreadth, even for an entire corpse.

As such, Kesef Mishneh’s interpretation seems very surprising. It would seem that there is indeed a significant disagreement between Maimonides and the Raavad: namely that Maimonides is referring to impurity passing from room to room—where a one handbreadth opening would facilitate its transfer, while the Raavad seems to state that there should not be a difference between the case of a close structure and our case here. In both instances, the transfer would depend on the size of the object imparting the impurity. An entire corpse only transfers if the opening is larger than four handbreadths by four handbreadths, and an olive-sized portion’s impurity transfers through an opening of one handbreadth by one handbreadth.

Practical Application

Ritual impurity refers to a dimension of evil which cannot be appreciated by mortal hearts and minds. Instead, it is as the Midrash states: "It is a statute which I (G‑d) ordained, a decree that I instituted."6

For this reason, most of the Torah's prohibitions remain pertinent today, while the laws of ritual impurity, by and large, applied only in the time of the Temple. This is because, whenever one observes evil, one must take precautions against it. When one is aware that an action is incorrect, steps will be taken to correct it. However, evil which we cannot detect, and which is deemed evil solely by virtue of G‑d's decree, conflicts only with a holiness revealed in Beis HaMikdash. It does not disrupt the reduced levels of holiness revealed in the present era.

For this reason, most of the laws concerning ritual purity which are practiced today, pertain solely to kohanim. Since they are endowed with an extra measure of holiness, they must protect themselves from ritual impurity. The general population on the other hand, need not concern themselves with the possible pollution of ritual impurity, which would only intervene with a level of holiness associated with the Temple.7