Chatzi Shiur

Rabbi Israel Chait

Written by a student




Rambam, Hilchos Shvisas Assar 2:3

“One who ate or drank less than a kabeitzah on Yom Kippur is liable, he is not liable for excision. Even though [consuming] a partial measure (chatzi shiur) is Biblically forbidden, we are only liable for excision for a [full] measure.”


Rambam, Hilchos Shavuos 5:7

“One who swore not to eat any amount of nivaila or treifa and then ate less than an olive’s bulk, he is culpable on his vow for we are not sworn (prohibited) against a chatzi shiur from Sinai.”



This appears to be an open contradiction. Hilchos Shvisas Assar says chatzi shiur is Biblically forbidden, while Shavuos says we are not prohibited on a chatzi shiur from Sinai. 

Gemara Shavuos 22b, Tosfos “Ahetira” says, 


“Since chatzi shiur is [only] an issur b’alma, it’s not considered as sworn and standing from Sinai.”  


What does “issur b’alma” mean? Is it prohibited or not?



In Chatzi Shiur, its reason—ta’am ha’issur—is incorporated into the nature of the prohibition. One who eats insufficient measure of prohibited foods—Chatzi Shiur—violates Torah because he might add to this measure, thereby meeting the prohibited measure. But Chatzi Shiur alone isn’t worthy of violation. The nature of Chatzi Shiur’s prohibition is its “ta’am” (the reason), and not the cheftzah—the substance, which is an insufficient measure. This is why Chatzi Shiur is not considered as that which we are “sworn against from Sinai.” In fact, the very term “Chatzi Shiur” implies an insufficient measure.


Under the severity of our swear at Sinai to accept Torah, Chatzi Shiur is extraneous. Yes, chronologically Chatzi Shiur is simultaneous with Torah, as it is derived from “Kol Chailev” (Lev. 3:17). This explains how Rambam says it is “Biblically forbidden” (Shvisas Assar). But logically, Chatzi Shiur is subsequent to a Torah prohibition of pork for example: the prohibition of a partial measure of pork can exist only subsequent to the primary prohibition of pork. So, logically, “we are not sworn (prohibited) against a chatzi shiur from Sinai” (Hilchos Shavuos), as Chatzi Shiur is a “secondary” prohibition [only existing subsequent to a primary prohibition]. Only once a prohibition of pork exists, can Chatzi Shiur come into existence. [Chatzi Shiur is prohibited extraneously, not for itself, but lest one eat more and the latter eating of pork adds to the first, creating a full measure. It is a prohibition that, by definition, is subsequent to a Torah prohibition.]

Chatzi Shiur  can’t come about simultaneously with the prohibition of pork. You can’t construe Chatzi Shiur as a “half pork prohibition”; it’s not an extension of pork. For if it was, it would be a prohibition against pork, which is sworn since Sinai. But by saying it’s not sworn since Sinai, the prohibition is not against pork per se. [This applies to any Chatzi Shiur, like writing 1 letter on shabbos. One isn’t culpable until he write 2 letters.]


The nature of Chatzi Shiur is that it is a secondary prohibition—[not primary like the prohibition of pork]—and that’s what is unique about Chatzi Shiur. Chatzi Shiur is the only D’Oraissa principle not considered “sworn from Sinai,” it’s not “Mushba v’Omade.” This explains Tosfos as well, “Since chatzi shiur is only an issur b’alma, it’s not considered as sworn and standing from Sinai.”  “Issur b’alma” means it is not a primary issur. 


You cannot have Chatzi Shiur as a secondary system that too is Mushba v’Omade. A secondary system cannot also be Mushba v’Omade, as that would impinge upon the first system being Mushba v’Omade.


One final point Rabbi Chait made was a quote from Rav Chaim: Stealing less than a pruta is not considered stealing any value whatsoever. Either one stole or he didn’t: one can’t steal “partially.” Diminishing a friend’s wealth is not a quantitative category. As the stolen object has no halachic value, repeated theft of less than a pruta—although measuring millions of dollars—is considered as no stolen quantity. The stolen object—less than a pruta—has no value and tis therefor not subject to completing a shiur through adding more stolen percentages of a pruta. Each percentage is not considered anything.