Literary critic Adam Kirsch is reading a page of Talmud a day, along with Jews around the world.

Before I began reading Daf Yomi, I was familiar with only a few Talmudic episodes—the famous ones that are regularly cited as examples of the Talmud’s wisdom or sensibility. Whenever I come across one of these passages in the course of my reading, there is a thrill of recognition, as though a piece of a puzzle had been slotted into place. That happened this week with one of the best known and most provocative incidents in the whole Talmud, the one known as “the oven of achnai.” This passage, in Bava Metzia 59b, raises profound questions about the nature of Talmudic decision-making and the relationship of the rabbis’ authority to the authority of God.

The route to the oven of achnai begins many pages earlier, with a point of financial law. The first part of Chapter Four of Tractate Bava Metzia establishes that a purchase is not complete until the seller delivers the goods to the buyer. This means there is a window of opportunity in any transaction for the seller to renege: If he has received money from the buyer but hasn’t yet handed over the goods, he can cancel the transaction and return the money. As I wrote in my last column, the rabbis severely discourage him from taking advantage of this loophole, condemning him with a biblical curse.

In Bava Metzia 49b, the rabbis discuss another type of unjust transaction, which they call “exploitation.” In a capitalist system, the rule is that sellers try to sell high and buyers try to buy low, and whoever makes the best deal wins. We follow the ancient Latin maxim caveat emptor, let the buyer beware: If you buy something and then find out you paid too much, or got a lemon, you have no one to blame but yourself. But the Talmud takes a different view, holding that for any commodity there is a fair price. A transaction that diverges from the standard price of any item is inherently unjust, because it constitutes exploitation of either the buyer (if the price is too high) or the seller (if the price is too low). Presumably, the exploited party consented to the transaction only because they were ignorant of the correct price, and it is against Torah law to take advantage of that ignorance, as stated in Leviticus 25:14: “And if you sell to your colleague an item that is sold, or acquire from your colleague’s hand, you shall not exploit your brother.”

This is one of those Torah laws that clearly needs to be made more specific if it is to function in everyday life. How do you quantify exploitation? The Talmud lays down the formula: “The measure of exploitation is four silver ma’a from the 24 silver ma’a in a sela, or one-sixth of the transaction.” In other words, if a seller charges one-sixth higher than the market price—or, conversely, if the buyer pays one-sixth less than the market price—the transaction is unjust. The exploited party then has two courses of action. He can nullify the transaction entirely, so that the item goes back to the seller and the money goes back to the buyer, or he can simply demand the exploiter return the extra profit he made by straying from the market price.

How much time does the exploited party have after the transaction to bring such a claim? The rabbis reason that the buyer has as much time as it would take “to show the merchandise to a merchant or to his relative.” This allows him to compare prices and discover whether he was ripped off, but it gives him only a reasonable amount of time to do so. A seller who is defrauded, however, is in a more difficult situation because he no longer has the item he sold, and so he can’t easily bring it to an expert for an estimate of its fair price. As a result, the rabbis do not set a time limit on the seller’s ability to bring a case for exploitation. This seems like it has the potential to create serious problems for the commercial system: What would happen if a seller brought a claim against a buyer a year or 10 years later? How could such a claim be proved, and what if the buyer no longer has the item he bought? But the rabbis believe that this is what justice requires.

Having established this principle, the rabbis go on to consider its limits and exceptions. According to Rabbi Yehuda, “There is no exploitation for a merchant”: that is, a man whose business is buying and selling goods can’t claim to be ignorant of the market price of those goods. “He knows how much his merchandise is worth,” Rav explains, and if he chooses to sell for a lower price than usual, it is only because “other merchandise happens to become available to him and he needs the money to purchase that item.” Here the rabbis acknowledge that sometimes it is actually in a person’s interest to accept an “unfair” price,” if he has a particular need for the money or the goods involved in the transaction.

This raises the question of whether the parties to a transaction can waive their right to sue for exploitation. One might think that because the law against exploitation comes from God, it is binding on both parties whether they want it to be or not. Rav draws an analogy with the law governing a husband’s obligations toward his wife, which include providing her with food and clothing. Because this is a Torah law, a woman cannot waive these rights even if she wants to. Even if she signs a contract that specifies that her husband will not provide her with food and clothing, he is still obligated to do so.

Does the same principle hold with exploitation? The answer, according to Rava, is that the parties can waive their rights to sue for exploitation, but only if they are both informed in advance that the transaction does not conform to fair market prices. If a seller charges 200 dinars for an item that is worth only 100 dinars, but informs the buyer that this is what he is doing, then the buyer can enter into the transaction and waive his right to challenge it later. The principle is informed consent: Just as a merchant cannot sue for exploitation because he is presumed to be informed about prices, so a lay person who is explicitly informed in advance cannot later claim to be exploited.

After dealing with monetary exploitation, the rabbis move to another type of sin: verbal abuse. “Just as there is a prohibition against exploitation in buying and selling, so there is exploitation in statements,” says the mishna in Bava Metzia 58b. The two types of mistreatment are juxtaposed in Leviticus 25, which follows the prohibition on fraud with the warning: “And you shall not mistreat one man his colleague; and you shall fear your God, for I am the Lord your God.” “The verse is speaking with regard to verbal mistreatment,” the Gemara explains, and the rabbis go on to condemn such mistreatment in very strong terms. It is particularly forbidden to say anything that will humiliate another person; this includes reminding a repentant sinner of his past misdeeds, or even just using a derogatory nickname. The Gemara compares such conduct with adultery, saying that both types of sinners are condemned forever to Gehenna. Indeed, “it is preferable for a person to engage in intercourse with a woman whose married status is uncertain and not humiliate another in public.” Or, in the words of Rav, “It is more comfortable for a person to cast himself into a fiery furnace than to humiliate another in public.” This insistence on respect and dignity is one of the keynotes of rabbinic ethics, and it appears in various ways throughout the Talmud.

It is at this point that the rabbis bring up the story of the oven of achnai. Achnai is the word for “snake,” and it refers to a style of building ovens that resembles a coiled snake: the clay oven is cut into horizontal segments and sealed with mortar. There was a dispute between the rabbis about whether such an oven could contract tumah, ritual impurity. The law is that only intact vessels can become tamei, and the rabbis disagreed about whether an achnai oven should be considered one intact vessel or a series of broken vessels stuck together. Rabbi Eliezer believed that the oven could not become tamei, but “the rabbis”—that is, the majority of the rabbis—disagreed.

In the ensuing argument, Rabbi Eliezer tried to support his position by calling down a series of miraculous signs. First, he caused a carob tree to jump a hundred cubits; then he made a stream flow backward; then, he made the walls of the study house collapse. The logic seems to be that only God could have performed these miracles, so God was clearly on Eliezer’s side. Finally, this was explicitly affirmed, when a divine voice (bat kol—literally, a “daughter of the voice”) was heard to say, “Why are you differing with Rabbi Eliezer, as the halakha is in accordance with his opinion in every place?”

But even this did not convince the rabbis, and Rabbi Yehoshua responded by quoting Deuteronomy: “It is not in the heavens.” That is, the Gemara explains, “Since the Torah was already given at Mount Sinai, we do not pay attention to a Divine Voice, as you already wrote at Mount Sinai, in the Torah: ‘After a majority to incline.’ ” In other words, since the Torah itself entrusts the power of legal interpretation to the majority vote of the rabbis, even a new sign from God cannot overturn the rabbis’ authority. According to Elijah the Prophet, when Yehoshua made this argument, God “smiled and said: My children have triumphed over me; my children have triumphed over me.”

This wonderful story seems to capture the whole ethos of the Talmud, and the way it elevates tradition, logic, and consensus over the charismatic and miraculous aspects of religion. The rabbis live in a postmagical age, when even signs from heaven count for less than human reason, and they are content to live in such an age. More, God is content on their behalf. God even takes pleasure in the ingenuity with which his children prove their self-sufficiency. The rabbis are, in a sense, God’s successors, having inherited his authority over the law. The genius of rabbinic Judaism was to arrange for this inheritance of the sacred, allowing the Jews to survive even in a disenchanted world.


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