Think about the last time you had to measure something without the assistance of an instrument: determining if your opponent’s tennis serve was in or out without the benefit of an electronic eye, perhaps, or lining up a painting without the use of a level. Dividing the last cookie between two eager siblings is a classic. In all cases, we assume there is an answer, even if we don’t have access to it: That is, we believe the serve was either in or out. We also believe the cookie can be divided perfectly (or perfectly enough, even if the siblings will always contend the other got the “bigger” half).
The Talmud has been grappling with a different dilemma of trying to make a call that is nearly impossible — determining which of twin male calves is a bekhor when they appear to have emerged from the womb simultaneously. To sort through this thorny case, the rabbis contemplate other problems where perfect measurement seems out of reach.
One such problem comes from the Torah’s case of a murder victim whose body is found lying in an open field between two towns. When no perpetrator can be found, Torah rules: “Your elders and magistrates shall go out and measure the distances from the corpse to the nearby towns. The elders of the town nearest to the corpse shall then take a heifer that has never been worked, which has never pulled in a yoke; and … bring the heifer down to an ever-flowing wadi, which is not tilled or sown. There, in the wadi, they shall break the heifer’s neck.” (Deuteronomy 21:1–4) The term for that unfortunate heifer is eglah arufah, or decapitated cow. Its job is to atone for the murder. Already, we can see that there is a similarity to our case, in which the true bekhor is unknown. The similarity increases when we consider a variant on the mystery murder victim case found in another mishnah:
Come and hear another proof from a mishnah (Sotah 45b): If the slain person was found precisely between two towns, the two towns bring two heifers between them — this is the statement of Rabbi Eliezer. What is the reason that each town must bring a heifer? Is it not because Rabbi Eliezer holds: With regard to matters that are in human hands, it is possible for two matters to coincide precisely?
In this specific case, the victim is found exactly midway between two towns — a set-up even more reminiscent of twin calves that emerge from their mother’s womb simultaneously: We don’t know which town bears responsibility for this murder victim, and we don’t know which calf is the true bekhor.
According to Rabbi Eliezer, the solution in the murder case is for each town to contribute a separate heifer for the required ritual. Effectively, both towns shoulder responsibility. That is because he believes it is possible for the corpse to be found exactly midway between the towns. Coming back to the newborn calves, the Gemara posits that if (according to Rabbi Eliezer) town elders can determine that a corpse lies exactly equidistant between two towns, and both can be held responsible, it ought to also be possible for a person to determine that twin calves were born simultaneously, and name each one a bekhor.
But wait — Rabbi Eliezer is not the only one to weigh in on the corpse lying at the midpoint between towns:
Rav Hiyya bar Avin says that Rav Amram says: The sages taught in a beraita: If the slain person was found precisely between two towns, Rabbi Eliezer says the two towns bring two heifers between them, but the rabbis say they bring one heifer in partnership and stipulate that it is brought for the town that is nearest.
According to Rabbi Eliezer, the two towns are both fully responsible for this corpse. However, the rabbis disagree. They rule that the two towns bring one heifer between them, and it will serve to atone for whichever (unknown but singular) town bears the responsibility. This stipulation now brings us back to the twin calves:
Rather, must one not conclude from it that the rabbis hold: It is impossible for two matters to coincide precisely, and this is true even with regard to matters that are in human hands? Indeed, conclude from it that this is so.
Not only are the rabbis concerned that it is not possible to know for certain if a corpse lies at the midpoint between towns — they don’t seem to think it is possible for the corpse to truly be midway between the towns. Similarly, it is not only impossible to know for certain that two calves emerged from their mother’s womb simultaneously — it is not possible for them to actually emerge at the same time. Therefore, we cannot have two bekhorot; there is only one, we just don’t know which it is.
And if that’s the case, just as two towns share the responsibility of the eglah arufah, rather than each shouldering the entire responsibility independently, in the case of the twin calves, the priest does not get both calves. Rather, the owner gets one calf, the priest gets the other, and we leave it up to Heaven to call it good.
In the case of the cookie, my mom z”l had her own workable solution: One sibling divides the treat and the other chooses which half to take. Tennis players, you’re on your own.
Read all of Bekhorot 18 on Sefaria.
This piece originally appeared in a My Jewish Learning Daf Yomi email newsletter sent on October 6, 2026. If you are interested in receiving the newsletter, sign up here.
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Source: My Jewish Learning
