In Chapter 8 of Tractate Bechoros, we continue to discuss the laws of uncertainties regarding pidyon haben. Mishnah 4 deals with a man who has two wives, and both gave birth together in a dark cave. The babies became mixed up, such that it is unknown which baby belongs to which mother. Various scenarios branch out from this situation.
Two Women Who Had Not Previously Given Birth and Gave Birth to Two Males:
The Mishnah begins: "Shtei nashim shelo bichru veyaldu shenei zecharim" - two women who had not previously given birth and gave birth to two males. Both are married to one man, and neither of them had given birth before. Both gave birth in a dark cave, and in the morning, two boys were found. Even though it is unknown which boy belongs to which mother, it is clear that both boys were born to mothers for whom this is their first birth, meaning that both are firstborns. Therefore, "nosen eser sela'im lakohen" - he gives ten selas to the kohen, five selas for each of them.
"Mes echad meihen besoch sheloshim yom" - if one of them died within thirty days. This refers to a case where the father gave the money to the kohen early, before the boys reached thirty days of age. It seems puzzling why he would do so, as the obligation of pidyon haben does not take effect until after thirty days. Rather, a kohen happened to be readily available, and he said to him, 'I am giving you the money now.' The son is not redeemed immediately; instead, the father stipulates that when the son reaches the thirty-first day, the redemption will take effect at that moment. Here, one of the boys died before the thirty-first day, and the father wants five selas returned to him.
"Im lakohen echad nasan" - if he gave it to one kohen - "yachazir lo chamesh sela'im" - he must return five selas to him. Since the kohen was only entitled to one redemption, he must return the remaining five.
"Im lishnei kohanim nasan" - if he gave it to two kohanim - he cannot extract anything from them. This means he gave five selas to each of two kohanim, without specifying which boy he was redeeming with them. Had he specified - 'I am giving you five selas to redeem my son Reuven,' and to the second, 'I am giving you five selas to redeem my son Shimon' - there would be no question here at all. If one boy died within thirty days, he would return to that kohen and demand his money, as he never became obligated in it. But since he gave it to each of them without specification, simply saying 'for one of my sons', it is unknown which kohen redeemed which child, and each of them deflects him with the claim of 'the burden of proof is on the one seeking to extract property from his fellow.'
The Dispute Among the Rishonim Regarding the Reason for Exemption:
Rashi, and similarly the Bartenura, explain that the father assumed the baby would reach thirty days, and since it died after twenty days, it retrospectively becomes clear that it was a nefel (a non-viable baby) and not a viable child - meaning it was born prematurely or its development in the womb was incomplete. According to this approach, if it were possible to know with certainty that the baby was not a nefel - for instance, if it was born so developed that by ten days old it was already walking and talking - the father would be obligated to give five selas for it even if it died within thirty days.
Tosafos strongly disagree with this: The Torah established that the obligation of redemption only takes effect after a month, and therefore it is completely independent of the uncertainty of whether the baby will survive or not. Practically, there is no difference between these views, since for a child who dies within thirty days, we can never definitively prove that he was not a nefel, unless we rely on modern technology. Regardless, the halachah follows the view of Tosafos, since this is a double doubt (safek sefeika), and there is no obligation in the mitzvah until the boy completes a full thirty days, which is on the thirty-first day.
Other Combinations of Babies with Two Women Who Had Not Previously Given Birth:
"Zachar unekevah" - a male and a female - in the morning, one boy and one girl were found in the cave. The male is certainly a firstborn, and the only unknown is who his mother is; therefore, "nosen chamesh sela'im lakohen" - he gives five selas to the kohen.
"O shenei zecharim unekevah" - or two males and a female - two boys and one girl were found. One boy is certainly a firstborn, but the second is in doubt: perhaps he is a twin and his sister was born before him, so he is not a firstborn. Therefore, the father gives a redemption for only one.
"Shtei nekevos vezachar" - two females and a male - or "shenei zecharim ushtei nekevos" - two males and two females. As long as there are two females in the cave, it is possible to say that one female is the firstborn of one mother and the second female is the firstborn of the second mother, and there is no firstborn son here at all. Therefore, "ein kan lakohen kelum" - there is nothing here for the kohen. The kohen cannot prove that anything is owed to him, and he collects nothing: the father does not redeem them, and even the sons themselves are not obligated to redeem themselves.
One Who Had Previously Given Birth and One Who Had Not:
A new scenario: A man has two wives, one who has already given birth in the past and one who has never given birth. The baby born to the one who has already given birth is absolutely not obligated in redemption, while the one born to the one who has not given birth - if it is a male, it is obligated in pidyon haben. Both gave birth in a dark cave, and in the morning, the babies were found mixed up, and it is unknown which baby belongs to which mother.
"Veyaldu shenei zecharim" - Even though it is not known which son belongs to which mother, it is clear that one of the sons was born to the mother giving birth for the first time and is obligated in redemption. Therefore, "noten chamesh sela'im lakohen" - he gives five selas to the kohen for that son who is the firstborn, whoever he may be.
"Mes echad mehen betoch sheloshim yom" - The father is completely exempt, since perhaps the son who died was the one born to the mother giving birth for the first time and he was the firstborn, while the surviving son was born to the mother who had given birth before, and was never a firstborn.
The father died and the sons are alive:
This is the exact same situation - two sons where one of them is a firstborn and it is not known who he is - except that the father died before he gave anything. Tosafos even wonders why the Mishnah repeats this law, since it is exactly like the previous Mishnah. Regardless, the estate owes five selas to the kohen. Before the estate is divided between the two sons, the kohen collects it, since it is clear that the estate owes the debt; but once the sons have divided the inheritance, the Tanna'im disagree:
Rabbi Meir: "Im nasnu ad shelo chaleku - nasnu". If the estate gave the five selas before the sons divided the inheritance between them, the giving is valid and cannot be taken back. "Ve'im lav - peturin" - if they did not give it and have already divided the inheritance, each brother is exempt, as they have the status of purchasers, and the debt to the kohen is merely an oral loan - an agreement not written in a document - and there is no obligation to pay it, with the result that the kohen receives nothing.
Rabbi Yehudah: "Nischayvu benechaseihem". Even though they divided the inheritance, the obligation rests upon their portions to fulfill the debt of five selas, and when the kohen claims it from them together, they must pay jointly. Some explain that in his opinion, they are not purchasers but heirs, and the concept of retroactive clarification applies here, so each pays his share; while others explain that even in his opinion they are purchasers, but since this obligation is written in the Torah, it has the status of a loan recorded in a document, as explained in the previous Mishnah.
"Zachar unekevah":
The final case in the Mishnah: The two women - one who had given birth before and one who had never given birth before - gave birth in a dark cave, and in the morning a male and a female were found mixed up, and it is not known who is the mother of each of them. In this case, "ein kan lakohen kelum" - the kohen is not entitled to anything, based on the rule of "the burden of proof is on the one seeking to extract property from his fellow," since it is possible that the daughter was born to the mother giving birth for the first time and she does not have a firstborn son, while the son was born to the mother who had given birth before and is not a firstborn, meaning there is no obligation of redemption here at all. And since the kohen cannot prove that the son was born to the mother giving birth for the first time, he collects nothing.