Talmudic pages

Bava Metzia 50

The math of exploitation.

Yesterday’s daf introduced us to the concept of ona’ah, exploitation. Ever bought a bottle of water at an amusement park you thought was priced way too high? The rabbis hold that there is only so much mark-up that is permissible on items for sale. Yesterday’s mishnah offered us a set of principles that define financial exploitation and its remedy: 

The measure of exploitation: Four silver ma’a from the 24 silver ma’a in a sela, or one-sixth of the transaction. Until when is it permitted to return the item? Until a period that would allow him to show it to a merchant or to his relative.

The first opinion in the mishnah (which we’ll discover is that of the rabbis) defines financial exploitation as a markup of more than one-sixth (or about 17%). If you are financially exploited in this way, you have the amount of time it would take to talk to someone who knows how much an item should cost to discover the exploitation and return the item. 

The mishnah then explains that this initial set of principles were updated by Rabbi Tarfon:

Rabbi Tarfon ruled in Lod: Exploitation is eight silver ma’a from the 24 silver ma’a of a sela, or one-third of the transaction. And the merchants of Lod rejoiced.

Rabbi Tarfon gave sellers a lot more room to raise prices — up to a markup of one third (33%). Huzzah for the merchants! But wait, there’s a catch: 

He said to them: The entire day it is permitted to renege.

They said to him: Let Rabbi Tarfon leave us as we were, and they reverted to the statement of the rabbis.

While the merchants initially rejoiced under Rabbi Tarfon’s new ruling because they could overcharge by much more, he also required them to take back merchandise all day long. (To those of us who are used to free returns within 90 days of purchase, that sounds totally reasonable. But no-questions-asked returns weren’t routine in the ancient marketplace.) Rabbi Tarfon’s ruling increased the merchants’ sense of uncertainty over both their inventories and their profits for much longer. And, apparently, they decided they would rather mark up items less and have greater financial certainty, so they reject Rabbi Tarfon’s adjustment. 

The Gemara on today’s daf examines these two positions — the rabbis and Rabbi Tarfon — and asks: What are the implications for buying and selling more broadly?

A dilemma was raised before the sages: According to the rabbis, if he paid less than one-sixth, is there a waiver immediately, or after the time that it takes the buyer to show the merchandise to a merchant or to his relative? 

Let’s unpack this question: If the person who overpaid for the item can return it and get his money back, then that means the original sale was not final. In fact, the Gemara seems to think that in the case of one who is financially exploited by the seller, the sale only becomes official after the time required to get a second opinion on the worth of the item has passed. But does that mean that all sales only become official after a certain time has passed? What if someone paid what was considered a reasonable markup, less than one-sixth? When do they actually acquire the item? 

The rest of the discussion gets pretty complicated, and goes on for several pages, asking a wide range of questions about the implications of this mishnah for the broader world of economic exchange. What I want to note here, though, is how the Talmud weaves together many different elements: a set of economic principles, a new rabbinic ethics of commerce, a story of legal change and public backlash, and an understanding that legal rulings in one case can and do affect a range of other cases. A small story about the math of financial exploitation is really about so much more.

Read all of Bava Metzia 50 on Sefaria.

This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on April 18th, 2024. If you are interested in receiving the newsletter, sign up here.

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