The Four Halachic Domains on Shabbos

The melacha of hotza'ah is built around halachic space. Before asking whether an object may be carried from one place to another, halacha first asks what kind of place each one is.

The Alter Rebbe opens the subject with the basic classification: “אַרְבַּע רְשֻׁיּוֹת לְשַׁבָּת: רְשׁוּת הַיָּחִיד וּרְשׁוּת הָרַבִּים, כַּרְמְלִית וּמְקוֹם פְּטוּר.” There are four domains for the laws of Shabbos: reshus hayachid, reshus harabim, karmelis, and makom petur (Shulchan Aruch Harav, Orach Chaim 345:1; see also Shulchan Aruch, Orach Chaim 345:1).

These names are halachic classifications rather than descriptions of ownership. A place used by many people can sometimes have the halachic status of a reshus hayachid, while a small feature standing in the middle of a public street can have a different status from the street around it. Dimensions, walls, openings, height, and the character of the surrounding area all matter.

Reshus hayachid

A reshus hayachid is the primary private domain of the Torah's laws of hotza'ah. The Alter Rebbe defines its basic form as an area enclosed by mechitzos ten tefachim high, with a usable interior space of at least four by four tefachim (Shulchan Aruch Harav 345:1).

This can be an ordinary enclosed room or courtyard, but the halachic category is broader than a building. A trench ten tefachim deep and four by four tefachim wide can be a reshus hayachid. So can the top of a sufficiently high and wide post or mound, under the rules explained in the same siman. Halacha recognizes a bounded, significant space as its own domain regardless of ownership.

A full reshus hayachid also has a distinctive rule concerning height. Its halachic airspace rises upward, unlike reshus harabim, whose relevant airspace is limited. This is one reason that the status of a ledge, wall, roof, threshold, or object cannot always be inferred from the ground beneath it.

Not every area that is a reshus hayachid min haTorah is automatically permitted for every form of carrying. Chazal imposed additional restrictions in a number of cases. The most important for an eruv is the restriction on carrying between separately occupied homes and their shared courtyard until an eruv chatzeiros is made. That distinction becomes important when considering what a valid eruv actually changes.

Reshus harabim

Reshus harabim is the public domain in which the Torah's prohibition of hotza'ah applies in its full form. The Shulchan Aruch and the Alter Rebbe discuss streets and marketplaces together with a set of physical and use-related conditions. Among the basic conditions stated by the Alter Rebbe are a width of sixteen amos, an uncovered area, and the absence of a surrounding wall (Shulchan Aruch Harav 345:11).

Those conditions are only the beginning of a large sugya. The poskim discuss how open a street must be, what surrounding walls accomplish, how traffic and public passage are measured, and the well-known question of shishim ribo, six hundred thousand. Those issues determine whether a modern street or city has the status of a complete reshus harabim. They are treated separately in Reshus Harabim in a Modern City.

For the mechanics of hotza'ah, the important point is simpler. If one place is a complete reshus hayachid and another is a complete reshus harabim, transferring an object from one to the other can constitute the Torah melacha of hotza'ah or hachnasah. Carrying an object four amos within reshus harabim is also a Torah prohibition.

Karmelis

A karmelis is neither a complete reshus hayachid nor a complete reshus harabim min haTorah. Chazal nevertheless gave it a restrictive halachic status so that carrying between it and the Torah domains, and carrying a significant distance within it, would not become ordinary permitted activity.

The Alter Rebbe summarizes the structure by saying that a karmelis was given some of the leniencies of reshus hayachid and some of the leniencies of reshus harabim (Shulchan Aruch Harav 345:25). Its precise boundaries therefore depend on measurements and surroundings. An area too small to form a karmelis may instead be a makom petur. An area with valid mechitzos can be a reshus hayachid. A street meeting the full conditions of reshus harabim has the status of reshus harabim.

The practical point is essential: calling an area a karmelis does not mean that carrying there is simply permitted. The Alter Rebbe rules that Chazal prohibited transferring between a karmelis and either a reshus hayachid or reshus harabim, and prohibited carrying four amos in a karmelis (Shulchan Aruch Harav 346:1, 5). The Torah-level and rabbinic classifications are different, but both govern actual Shabbos practice.

Makom petur

Makom petur is the fourth category. Its name literally describes an “exempt place,” but it is a technical classification, not a general shortcut around the laws of hotza'ah.

A classic example is a small raised place in reshus harabim that is at least three tefachim above the ground but does not have an area of four by four tefachim. Depending on its exact height, width, and surroundings, it can be too small to become a separate karmelis or reshus hayachid and therefore have the status of makom petur (Shulchan Aruch Harav 345:13, 25-27; Shulchan Aruch, Orach Chaim 345:19).

The details matter. A feature lower than three tefachim may be halachically absorbed into the ground around it. A feature four by four can acquire a different status. A small place situated in a karmelis does not necessarily function the same way as the corresponding feature in a reshus harabim. The term therefore cannot be applied merely because a surface looks small or inconvenient to use.

Nor does passing an object through a makom petur automatically break a transfer into permitted pieces. The Alter Rebbe rules that if an object moves from reshus hayachid to reshus harabim through a makom petur without coming to rest there, the intermediate space does not interrupt the hotza'ah (Shulchan Aruch Harav 346:1). The separate ideas of akirah and hanachah are explained in Transferring an Object From One Domain to Another.

Why the classification has to come first

The same physical movement can have a different halachic character depending on the domains involved. Moving an object from a house into a true reshus harabim is not the same halachic case as moving it into a karmelis. Moving an object within a valid reshus hayachid is not the same as carrying it four amos in reshus harabim. A threshold, wall opening, sidewalk feature, or enclosed courtyard can itself require classification before the movement can be analyzed.

That is why the laws of an eruv begin with domains. Its physical components must create or preserve the halachic domain required for carrying, and its communal component addresses a separate Rabbinic restriction within that enclosed area. Only after those questions are settled can the practical act of carrying be evaluated correctly.