Our Gemara at the end of 30b, continuing into 31a, quotes a dispute between Beis Shammai and Beis Hillel regarding how to count the volume of a chest. This relates to the idea that if it holds more than forty se’a, it is not considered a utensil because it is so large, and therefore is not susceptible to ritual impurity. It is based on a Mishna in Keilim (18:1).

A wooden chest that is large enough to contain forty se’a is not susceptible to contracting ritual impurity, since it is no longer considered a vessel. In determining its capacity, Beis Shammai say that it is measured on the inside, and Beis Hillel say that it is measured on the outside, so that the volume of the walls of the chest itself is included in the measurement.

There is an observable pattern throughout most of the disputes between Beis Shammai and Beis Hillel whereby Beis Shammai is consistently more stringent and Beis Hillel consistently more lenient. In this case as well, you’ll notice that Beis Shammai counts only the inside volume, while Beis Hillel counts the external volume as well, therefore allowing for a larger number of chests to be consider non-conductors of impurity..

Is there something deeper to understand about this pattern? Malbim on Devarim (19:1) offers an ingenious explanation of this tendency. Malbim suggests that the House of Shammai represents a spiritual ideal—namely, that the intellect can be elevated through engagement in spiritual matters and abstention from physical lusts and desires to the extent that it can attain an Edenic state of Adam prior to eating from the Tree of Knowledge. If this is attained, a higher level of immortality of the soul is achieved, insofar as the intellectual soul can divest from the body at will, allowing for transcendent states even prior to death and higher levels of attainment in the World to Come. This accounts for why the House of Shammai’s rulings are often more stringent, because the focus is on abstinence and spiritually pure states. The House of Hillel endorses a more temperate approach—serving God in this world by engaging in physical acts while also remaining devoted to God.

The dispute found in Mishna Sukkah (2:7) can be understood in accordance with the Malbim on both a halachic and metaphysical level:

One whose head and the greater part of his body were within the sukkah and his table within the house: Beis Shammai say it is invalid, and Beis Hillel say it is valid.

Here again we find the House of Hillel choosing the more lenient position. Malbim adds a mystical layer of meaning to this Mishna. The House of Shammai allows for no compromise; one must completely disengage from the comforts of this world (the home) and dwell fully on the spiritual plane (the sukkah). The House of Hillel, however, advocates moderation. One may have his head and the greater part of his body in the sukkah (the spiritual sphere) while still remaining partially engaged in the physical world (the lower part of his body remains in the home).

This idea is also reflected in a teaching of the Arizal that in the World to Come the halacha will be in accordance with the House of Shammai (Sefas Emes, Korach 5647). Meaning, in a post-Messianic world, people will be able to live on this ideal plane of disengagement from physicality, in accordance with the principles of the House of Shammai.

We can add to the Malbim’s mystical take on Beis Shammai and Beis Hillel regarding the Mishna in Keilim (18:1). Beis Shammai is more strict, requiring forty se’a of volume to be reached only by the internal capacity before the vessel can be exempted from impurity, whereas Beis Hillel allows one to include the total area, including the outside and the thickness of the walls, to reach forty se’a. Metaphysically, Beis Hillel allows the outside—earthly experience and environment—to be included in the measurements required to achieve purity, while Beis Shammai requires uncompromising internality to achieve purity.

In addition, one can apply the Malbim’s principle to another dispute between Shammai and Hillel regarding shaatnez and tzitzis. According to Beis Hillel, one may wear a linen garment even though the fringes containing the blue thread are made of wool, which ordinarily would be a forbidden mixture of wool and linen (Devarim 22:11). According to Beis Shammai, however, this mixture is still ‘forbidden, and therefore a linen garment is exempt from the obligation of tzitzis (Menachos 40a).

Let us consider the sources of these materials. Wool comes from sheep, and linen comes from flax fibers. A shepherd produces wool, while a farmer produces linen. Notably, our forefathers—Avraham, Yitzchak, and Yaakov—as well as Moshe and Dovid Hamelech were shepherds. The sons of Adam and Chava, Kayin and Hevel, were pitted against each other in these opposing professions: “Hevel became a keeper of sheep, and Kayin became a tiller of the soil” (Bereishis 4:2). The commentaries attribute significance to each brother’s chosen occupation. Rabbenu Bechaye (Bereishis 46:32) reflects on the nomadic qualities of shepherding, which involve separation from cities and metropolitan life, often associated with sin and materialism. The farmer, on the other hand, is tied to his land and possessions and embedded in a city or state structure. While modern readers may associate farming with rural simplicity, in ancient times agriculture was the foundation of urban civilization, as opposed to nomadic life.

As Malbim explains, Beis Shammai advocates an ideal withdrawal from the pleasures and pursuits of this world, while Beis Hillel advocates moderation. Accordingly, the dispute about wearing shaatnez with tzitzis reflects this same underlying truth. Beis Shammai affirms the ascetic, nomadic life symbolized by shepherding and wool garments; only such garments are considered a Jewish cloak obligated in tzitzis. Beis Hillel accepts that one cannot fully withdraw from society in this world. One may be part of an agrarian, settled civilization—symbolized by linen—and still fulfill the mitzvah of tzitzis without contradiction to spiritual pursuits. Tanya, Iggeres HaKodesh (13) offers a similar understanding of Beis Shammai and Beis Hillel, though it does not develop it explicitly on a practical level.