A Lottery over Life (Column 438)

This past Shabbat I spoke in the synagogue about the story of Moses and the two quarreling Hebrews (Datan and Aviram), and I examined a complex case of mutual pursuit. Beyond the very contemporary question of what to do when someone witnesses a duel in the Wild West or in eighteenth-century France, I argued that this discussion also has more practical ramifications (see the article in Mida Tova for Parashat Shemot, 5767).

The Midrash: Gilui Milta

The discussion begins with Midrash Rabbah on the parashah (Shemot Rabbah, Parashah 1, §29):

“Another interpretation: ‘Nitzim’—they intended to kill one another, as it says (Deut. 25), ‘When men strive together.’ And R. Elazar said: Scripture is speaking of a case warranting death. ‘And he said to the wicked one: Why do you strike your fellow?’—it does not say ‘you have struck’ but ‘you strike’; from here we learn that once a person raises his hand to strike his fellow, even if he has not struck him, he is called wicked. ‘Your fellow’—who is wicked like you—teaches that both are wicked.”

The Midrash states that Datan and Aviram sought to kill one another; that is, there was mutual pursuit. It compares this to the verses in Deuteronomy (25:11–12):

“When men fight together, a man and his brother, and the wife of the one draws near to save her husband from the hand of the one striking him, and she puts out her hand and seizes him by his private parts—then you shall cut off her hand; your eye shall not pity.”

At first glance it appears that the Midrash learns by way of gezerah shavah that “strife” (nitzah) means an attempt to kill—that is, a case warranting death. This, as I have seen, is how the Midrash’s commentators usually understand it. One should understand that according to this it is not a full-fledged gezerah shavah but what is called gilui milta—a lexical elucidation (see Enzi"t s.v. “Gilui Milta,” and at the beginning of s.v. “Gezerah Shavah,” on the two types of gezerah shavah). The early authorities note that there are derivations that look like a gezerah shavah but are in fact gilui milta, namely, learning the meaning of a word from a biblical parallel. Here the Midrash learns the meaning of the word “nitzim,” and from the parallel it concludes that this is a case warranting death.

The Midrash: An Interpretive Gezerah Shavah

But from the Midrash’s own language one can see that this is not gilui milta but a gezerah shavah. The wording itself makes clear that the term “nitzim” is not specifically about death, for the Midrash says “Scripture speaks of a case warranting death”—implying that there are also other kinds of cases, ordinary quarrels (whose aim is not killing). If so, the Midrash itself indicates that “quarrel” (merivah) is the general sense, not necessarily one of killing. The derivation teaches that here it is a special kind of quarrel—a quarrel warranting death. Thus, this is not gilui milta but an interpretive gezerah shavah, namely, a gezerah shavah that does not legislate a law but interprets the events and verses.

This can also be seen in the Bible itself, in Exodus 21:22–25:

“When men fight and strike a pregnant woman, and her children come out but no harm follows, he shall surely be fined as the woman’s husband shall lay upon him, and he shall pay as the judges determine. But if harm follows, then you shall give life for life: eye for eye, tooth for tooth, hand for hand, foot for foot; burn for burn, wound for wound, bruise for bruise.”

Here it seems that this is not necessarily a quarrel warranting death, but an ordinary fight between two men that escalated into injury or death to a third party, a woman.[1] Thus it is not correct that the word “yinatzu” (“they fight”) necessarily means a fight to the death. If so, whence do we know that in Moses’s case it was specifically a quarrel warranting death? Therefore the Midrash brings a gezerah shavah from the verses in Deuteronomy to prove this. As noted, a gezerah shavah usually teaches a legal rule, but sometimes there is an interpretive gezerah shavah, and it would seem that this is the case here. Yet I will now argue that this is in fact a legal gezerah shavah (or at least an interpretive gezerah shavah with legal significance).

The Midrash: A Legal Gezerah Shavah

The Midrash formulates its conclusion thus: “Nitzim—they intended to kill one another.” Above I explained that the novelty is that this was a quarrel warranting death. But in my view the emphasis is not on the word “to kill” but on “one another.” That is, nitzim means a quarrel (whether warranting death or not), and a quarrel is mutual. When one person pursues another to kill him, that is not a quarrel and we would not describe it as “they are contending (nitzim).” A quarrel is when both contending sides are pursuing one another—mutual pursuit. The Midrash learned from the verses in Deuteronomy that the quarrel in question was mutual. Beyond that, it was a quarrel warranting death—but the point is that it was a mutual quarrel in which both sides wished to kill one another (not merely argue).

Note the interpretive novelty here. Moses turns to one of them and says, “Wicked one, why do you strike your fellow!”[2] One might have thought from this that only one of them was wicked and was pursuing the other. Hence we learn from the gezerah shavah that there was mutual pursuit. Indeed, the continuation of the Midrash states this explicitly: “‘Your fellow’—who is wicked like you—teaches that both are wicked.” In other words, both were pursuing one another and both were wicked. When Moses said “Wicked one, why do you strike your fellow,” he likely addressed both of them, telling each that he is wicked for striking his fellow—even if that fellow is himself wicked. In other words, the Midrash teaches that even in a case of mutual pursuit there is a law of rodef (pursuer), and each of the two is called wicked. This is already a legal novelty. Thus, the gezerah shavah that teaches us it was a mutual quarrel is indeed interpretive, but it has a legal implication: even in mutual pursuit, the law of rodef applies to both sides.

How is this learned from the gezerah shavah? For that we must turn to the sugya in Bava Kamma 28a:

“Come and hear: ‘then you shall cut off her hand’—[this means] monetary payment. What, is it not when she cannot save [her husband] by other means? No—when she could save by other means; but if she could not save by other means, she is exempt.”

The Gemara understood that the woman acted under the law of rodef (to save her husband). Therefore, if she had another way and nonetheless injured the pursuer, she must pay damages; but if she had no other way, she is exempt. Yet a difficulty arises: as we saw, there was mutual pursuit between the two combatants. Does the law of rodef apply in such a case? From the Gemara’s interpretation of the verses here we see that it does—namely, despite the mutual pursuit, the law of rodef applies, and the woman may harm one side even though the pursuer she harms is himself being pursued by her husband.

That is apparently what our Midrash learns from there to our parashah. From those verses we see that even in mutual pursuit the law of rodef applies; therefore here, too, both are considered wicked and both have the status of rodef. If so, this is truly a gezerah shavah and not merely gilui milta (lexical learning). Moreover, it is not only interpretive, but interpretive with legal consequence: it teaches the law of mutual pursuit.[3]

However, as we shall now see from at least two sources, in such a situation there may be no law of rodef.

Mutual Pursuit: The Jerusalem Talmud

The well-known Mishnah in Ohalot (7:6) speaks of a fetus endangering its mother:

“A woman who is in hard labor—one cuts up the fetus in her womb and removes it limb by limb, for her life precedes his. If most of it has emerged, one may not touch it, for one life is not pushed aside for another.”

The Mishnah distinguishes between a fetus endangering its mother, where we kill the fetus because her life takes precedence, and a case where the head has already emerged, in which case we leave the situation as is. The Bavli, Sanhedrin 72b, explains the latter by saying there is no law of rodef here because “from Heaven he is being pursued” (mishmaya kardefu lei). So why, when it is still a fetus, do we kill in such a case? Because his life does not yet have the status of a full human life, and therefore the mother’s life takes precedence (the Rambam gives a slightly different rationale, which I will not expand on here). But the Yerushalmi (end of Shabbat, and Sanhedrin 8:9) explains the prohibition to kill the newborn whose head has emerged as follows: “You do not know who is killing whom (who is the pursuer).” There is mutual pursuit; and in such a case, the rule is that “sitting and not acting” (shev ve’al ta’aseh) is preferable. That is, it is mutual pursuit and therefore there is no law of rodef, and one must not intervene.

True, in the Bavli, which explains the law differently, one might say it disagrees with the Yerushalmi and holds that even in mutual pursuit the law of rodef applies. Recall that we saw the same in Midrash Rabbah cited at the beginning.

Mutual Pursuit: Rabbi Shlomo Eiger

Rabbi Shlomo Eiger likewise concludes (as cited in R. Akiva Eiger’s Hiddushim to Ketubbot 33b) from a different sugya. He begins by posing the question:

“I have a doubt regarding two who pursue one another to kill—each after the other—and both began simultaneously (similar to what is found in the Rosh and in Shulchan Aruch, later §421:13, regarding two who injured one another, that one pays the excess of the full damage—specifically when they began simultaneously). If an observer is permitted to kill either one of them or not, for in such a case neither has the status of a rodef to justify saving [the other] with his life, since just as he is a pursuer of his fellow, so too he is pursued by his fellow.”

Up to here, he is in doubt about the law in mutual pursuit: whether both have the status of rodef such that a bystander may kill either one (but not both), or perhaps there is no law of rodef at all, since rodef applies only in an asymmetric situation.

He then seeks to resolve the doubt from the sugya in Sanhedrin, which deals with the Exodus verses we cited regarding two men who fight and strike a pregnant woman. Recall that the verses there indicate that if the woman dies, the one who killed her is liable to death; but if only the fetuses were lost, he must pay damages (the value of the fetuses).

The Gemara in Sanhedrin 74a cites the view of Rabbi Yonatan ben Shaul:

“As it was taught: Rabbi Yonatan ben Shaul says: If a pursuer was pursuing his fellow to kill him, and [the rescuer] could have saved him by [injuring] one of the pursuer’s limbs, and did not save [in that way], [but killed him], he is executed on his account.”

According to R. Yonatan ben Shaul, if it was possible to save the pursued by injuring one limb of the pursuer, and the rescuer killed the pursuer nonetheless, he is liable to death. His proof is from those verses:

“What is the reason of R. Yonatan ben Shaul? As it is written, ‘When men fight (together)…’ and R. Elazar said: Scripture speaks of a case warranting death, as it is written, ‘But if harm follows, then you shall give life for life’; and even so the Torah said, ‘If no harm follows, he shall surely be fined.’ If you say it was possible to save by [injuring] one of his limbs and it was not permitted to save by taking his life, then we can find a case where he pays—namely, when he could have saved by one of his limbs; but if you say that even when it is possible to save by one of his limbs it is still permitted to save by taking his life, how can we find a case where he pays?”

The one who killed the woman was pursuing his fellow, and in the process either killed the woman or caused damage. If he only caused damage, he must pay, even though as a pursuer he is liable to death, which would ordinarily exempt him from payment (kim lei be-derabah minei).[4] We are compelled to say it was a case where the pursued could have been saved without killing the pursuer; in such a case the pursuer is not liable to death and it is forbidden to kill him, and therefore he is liable for the monetary damage he caused. This is the proof for R. Yonatan ben Shaul’s view, who imposes the death penalty on one who kills a pursuer when he could have saved by injuring a limb.

R. Shlomo Eiger then resolves his doubt from here:

“In that verse, ‘and if no harm follows,’ it says ‘and they strike a pregnant woman’—in the plural. This can be interpreted in two ways: either that both of them struck her (the two men who fought together), or that ‘and they strike’ means either one of them, as Ibn Ezra explains the word there (on Exod. 21 in Parashat Mishpatim).”

If both combatants struck her, this is difficult:

“In that case, one may challenge R. Yonatan ben Shaul’s proof in Sanhedrin: for one can say that the verse is to be interpreted thus—‘When men fight… and they strike’—meaning both struck her; ‘if no harm follows, he shall surely be fined’—one of them, namely the pursued, for a pursued person who breaks vessels is liable. And if you say: why, then, pay all the damages and not just his half?—Not so, for one can say he pays all of it by the rule of R. Natan: wherever one cannot collect from this one, he collects all from the other (see Bava Kamma 53 and Shulchan Aruch 410:35)… And the verse states, ‘But if harm follows, then you shall give life’—meaning any life: the life of the pursuer and the life of the pursued who sought to save himself with the life of the pursuer; since he intended to kill, and the result was that he killed the woman, he is executed for her—one who intended to kill this person and killed another is liable. And because he is a pursued person there is no exemption, just as he is not exempt when he breaks vessels, so too he is not exempt if he killed a person.”

If both of them struck her, one can refute R. Yonatan ben Shaul’s proof, for perhaps the pursued is the one who killed the woman, and then it is clear he must pay the damages. He intended to kill the pursuer and accidentally struck the woman; and the halakhah is that one who intended to kill one person and killed another is liable.

Hence, if R. Yonatan nonetheless brought proof from here, he clearly could not interpret the verse as both killing her:

“We must say that R. Yonatan ben Shaul holds that the verse cannot be interpreted that way, for if so the end of the verse would be difficult—‘But if harm follows, then you shall give life for life’; if ‘and they strike’ means both struck, there is no liability for death, for it would be like ten who strike a man and kill him, where all are exempt (Sanhedrin 78a). Therefore ‘and they strike’ must mean ‘this one or that one,’ and then the question arises: if the pursuer struck, why should he pay? He had made himself liable to death.”

The reason is that if the verse means they both killed her together, one cannot understand why they would be liable to death, since when two kill together they are exempt.

But he immediately adds that even the alternative reading is difficult:

“Yet on this reading the reverse difficulty arises: how can the verse be set in a case where it is possible to save by injuring a limb, if the one who struck was the pursued? Why should he be liable to death if harm followed? Granted that one who intended to kill this one and killed that one is liable [as the Rabbis prove against R. Shimon in Sanhedrin 79], still, when one intended to kill a non-viable (nefel) and killed a viable person, the Sages agree he is exempt. And here the pursued was permitted to kill the pursuer—even if he could save by injuring a limb—so the pursuer, with respect to him, has the status of a non-viable, for whom the pursued is not liable; if so, when he killed the woman, he should not be liable to death…”

If it is not symmetric, but there is a pursuer and a pursued, then one cannot obligate the pursued, since he is permitted to kill his pursuer. If he attempted to kill the pursuer and struck the woman, it is as though he intended to commit a permitted killing (like killing a non-viable fetus) and hit a different person—he should be exempt.

Therefore he concludes that according to R. Yonatan ben Shaul the verse must be understood as follows:

“We must say [according to the view that the pursued is always permitted to kill him] that the verse ‘When men fight’ is where both began simultaneously in a quarrel warranting death, each coming to kill the other; and since neither has the status of a pursued with respect to the other and neither is permitted to kill the other, the other has the status of a fully viable person with respect to him; therefore, when he kills the woman he is liable.”

We must conclude that, for R. Yonatan ben Shaul, the verse speaks of a case where both simultaneously pursue one another, and in such a case neither has the status of pursuer or pursued, and neither is permitted to kill the other. Consequently, if they kill the woman, they are liable; and if they only caused damage, they must pay (for they do not have the status of rodef). From here he proves that where two people mutually pursue one another, neither has the law of rodef, as we saw in the Yerushalmi above.

I note that his proof can be countered in several ways, but I will leave that aside here.

Two Ways to Read the Conclusion

The conclusion from these two sources is that in mutual pursuit the law of rodef does not apply. This would seem to contradict the Midrash, which indicates that the law of rodef does apply. I noted that perhaps the Midrash follows the Bavli, which disputes the Yerushalmi. Yet it seems possible to reconcile the sources nonetheless.

Let us preface with two possible readings of the Yerushalmi’s and R. Shlomo Eiger’s conclusion:

1. The law of rodef exists only in asymmetric cases. In a symmetric case, neither has the status of rodef.
2. The law of rodef exists even in symmetric cases, but where both mutually pursue each other it is forbidden for an outsider to intervene, for in any event one of them will die and intervention accomplishes nothing. In a symmetric case, “sitting and not acting” is preferable; we are to leave them to their fight, and whoever dies, dies. We are not meant to decide who dies, for neither has priority over the other.

It seems to me that under either possibility—especially if the case is Datan and Aviram—when two such pursuers stand in a symmetric situation, our only option is to wish both sides “good luck” and watch the bout with some satisfaction. Indeed, Moses rebukes one of them—or both (as we saw in the Midrash above)—but there is no hint in the verses that he actually intended to kill either of them (as they suspected him).

Note that under the second possibility the law of rodef does exist even in the symmetric case. Both are rodfim, yet due to the symmetry one must not intervene to kill either of them. One might argue that in principle it would be permitted to kill, but we lack any way to choose which one, since both are in the same state and equally culpable. Symmetry compels non-intervention. But that could be solved by a lottery. One could draw lots to decide which of the two to kill. My claim is that this is not the issue: in a symmetric case there is no fundamental permission to kill at all; it is not merely a problem of choosing one over the other.[5]

Returning to the two interpretations, the first seems implausible. I preface by noting that the law of rodef is regarded in halakhah as a kind of capital liability: killing the pursuer is not only to save the pursued, but has a punitive dimension. The clearest indication is that if the pursuer breaks vessels on the way, he is exempt from paying for them, like one who is liable to death and money and does not pay (kim lei be-derabah minei; see Rava in Sanhedrin 74a, codified in halakhah). Indeed, in Afikei Yam II §40 it is shown at length that the death of the pursuer has a punitive element. If killing the pursuer were only for the sake of saving the pursued, one might say that in the symmetric case there is no permission to kill and the law of rodef would not apply. But if there is also punishment for being a pursuer, it is implausible that when both pursue each other, each is thereby exempt from the punishment due to him. In such a case both are guilty, and it is more reasonable to say that both are liable to death as rodfim (I speak of a case where both initiated and are culpable, as R. Shlomo Eiger explained). Of course, in practice we would not kill both, as nothing is gained thereby; but the law of rodef applies to both. Why, then, according to the Yerushalmi and R. Shlomo Eiger, do we not actually kill them? Because the pursuer is not liable to death in the usual punitive sense: if it is possible to save by injuring a limb, there is no permission to kill. The saving of the pursued must accompany the permission to kill. He may be liable to death as a pursuer, but we do not kill him unless doing so saves the pursued. In the symmetric case, killing the pursuer does not lead to salvation; therefore, though both have the law of rodef, there is no permission to kill either of them.[6]

The conclusion is that the second possibility is likely correct: in mutual pursuit both have the law of rodef, but there is no permission to implement it. This also reconciles the apparent contradiction between those sources and the Midrash cited at the outset. The Yerushalmi and the Sanhedrin sugya, too, hold that there is a mutual rodef status in a symmetric case, but there is no license to act upon it.

A Practical Difference for Mutual Rodef: Separating Conjoined Twins

It would seem that the conceptual analysis above has no practical difference (nafka minah). As we saw, even if both have the law of rodef, there is no permission to implement it by killing either of them. Why, then, was it important for the Midrash to teach via gezerah shavah that even in mutual pursuit the law of rodef applies? Is this merely a hypothetical halakhah (with ramifications for, say, kiddushin)? I think there are practical implications, and one possible example is the case of separating conjoined twins.

Conjoined twins are twins physically joined, and in some cases they share organs—sometimes even a single heart or a single brain. In certain situations, it is known that if the status quo remains, both will die within about nine months. The question is whether one may perform separation—surgically separate them so that one receives the shared organ (heart or brain) and the other is left to die. If the surgery succeeds, we save one twin, whereas if we leave them as they are, both will die.

Some fifteen years ago I heard of a case of conjoined twins (I think they shared a heart). The halakhic authorities ruled to the parents that there was no permission to perform separation, since it would constitute murder; as a result, both were left to die. This outraged me, for my immediate intuition was that in such a case it is permitted—indeed obligatory—to perform the separation, since at least one life will be saved. What is the point of scrupulously avoiding murder if the outcome is the loss of two lives? The prohibition of murder aims at saving or preserving life, whereas here, because of that prohibition, we lose lives. This struck me as utterly illogical.

I therefore delved into the sugya, reviewed the sources and considerations on all sides, and the opinions of the decisors (the result is my article in Techumin on separating conjoined twins). To my astonishment I found a full consensus among leading halakhic authorities that there is no permission to perform such separation in that scenario. I refer to a symmetric case—where there is no way to attribute the organ to one more than the other, and each twin’s chance of survival is identical. In short, there is no side consideration enabling us to choose whom to save. In such a case, the halakhic consensus prohibits surgery, since it is murder. See my article cited above.[7]

One can view the case of separating conjoined twins as mutual pursuit (albeit without intent—but an unintentional pursuer is still a pursuer)[8]; yet the conclusion there differs from the earlier cases discussed above. In those cases, the expectation was that without intervention one of the two would die; hence I explained that even if the law of rodef applies, there is no permission to implement it. In the case of conjoined twins, without intervention both will die; therefore, here there is room to implement the law of rodef and intervene (i.e., to perform separation and kill one under the law of rodef).

I note that an even clearer implication for mutual pursuit arises where two adult, intentional pursuers (as in Moses’s case) are engaged in mutual pursuit and, absent external intervention, both will die. In such a case, if we assume the law of rodef applies, there is certainly justification to intervene and implement it in order to save one life. Thus, even aside from the more problematic twins case, mutual pursuit among adults can have practical consequences if we recognize the law of rodef on both.

As I will now try to show, there are two paths to permitting separation surgery in conjoined twins in the scenario described: either on the basis of mutual rodef, or even without invoking rodef.

Permitting Separation of Conjoined Twins via Mutual Rodef

Here I present a permissive ruling based on the assumption that in such a case there is indeed mutual rodef. True, one could say that “from Heaven they were made to pursue” (mishmaya kardefu), but where both parties have been naturally placed in this situation, it may nonetheless be that the law of rodef applies. In the case of a fetus and its mother there is no rodef because the mother’s life is endangered by the fetus and not vice versa (though according to the Yerushalmi this may appear mutual). In such a case there is no license to kill the fetus whose head has emerged, for he is not a pursuer; Heaven placed him thus. But in conjoined twins both have been placed in this state, and therefore killing one is called for. Leaving both to die because there is no law of rodef is illogical; the absence of rodef status ought to ease their situation (i.e., increase our obligation to save them), not worsen it.

Assuming there is mutual rodef, there is permission to kill either one under that law. Of course, there is no sense in killing both, for nothing is gained thereby; but killing one will save the other. The question is how to choose whom to save, given symmetry. Several of my interlocutors argued on this basis for non-intervention; therefore they sided with the decisors who prohibit surgery in such a case. But, as I have already mentioned, there is the option of a lottery; in my view we should draw lots and save the one who is chosen (see the next column).

It is important to note that if in such a case there were no law of rodef on both, a lottery would not help and would not be permitted. A lottery cannot permit murder. If there is no basic permission to kill either of them, a lottery does not change that. But if both have the law of rodef, then killing either one is not murder, and the only problem is how to choose who is saved and who is killed. In that situation, a lottery is the natural solution. True, my interlocutors argued that there is a prohibition to cast lots over lives; I will address that in the next column.

Permitting Separation of Conjoined Twins Without Mutual Rodef

Now I will assume that in conjoined twins there is no mutual rodef. I wish nonetheless to argue that it is permitted (indeed obligatory) to draw lots, perform the separation, and thus save the one chosen. To explain: imagine two adult twins who must decide for themselves; they would presumably choose to cast lots to determine which one will be saved. Recall that the alternative is that both die; thus a lottery is the preferred option for both, since it gives each a 50% chance to live.

Could one possibly forbid two adult twins from deciding to draw lots in such a scenario regarding themselves? Surprisingly, this argument was raised repeatedly in my debates on the sugya, though to my mind it is wholly illogical. I explained that this is akin to a person on the roof of a burning building considering a jump. Suppose there is a 50% chance he will die from the jump, but a 50% chance to live; whereas if he does not jump he will certainly die. Is it conceivable to forbid him to jump because he is a “possible suicide”? Is it conceivable to forbid a bystander from pushing him down because this is a “possible murder”? Any sensible person understands that in such a case one must jump—or push him down—to give him a 50% chance to live. Likewise, adult twins can decide to draw lots to gain a 50% chance of survival.

What about infant twins who are not of age and cannot decide? In such a case, the court (beit din) is “the father of orphans,” and must decide for them what they themselves would decide were they of age. Therefore, in my view, the court should draw lots on their behalf and send them for separation surgery—precisely as they would have done for themselves.

Note that to permit a lottery this way, there is no need to posit mutual rodef. Even without liability to death, it is permitted to perform the separation, for we are not “killing” anyone: the one who dies from the surgery would in any case have died; the surgery saves the other, who would otherwise have died as well. In the Chazon Ish’s terms, this is an act of rescue, not of killing/murder.

I mentioned that one interlocutor claimed there is a prohibition to cast lots over lives. I will address that claim in the next column.

[1] See discussion in Sanhedrin 74a (the sugya will be cited below). At least according to one view, even there it concerns a case warranting death.

[2] Only this Shabbat I read in Rabbi Ilay Ofran’s book, Torah of the Soul (in the essay beginning p. 201), that in Scripture the word “lama” is not an interrogative but an expression of protest or rebuke; “madua” expresses a question expecting an answer. Hence I was careful here not to place a question mark (prior to implementing the teaching).

[3] One may note that the interpretation that applies the law of rodef is that of the Gemara. The verses themselves state “you shall cut off her hand”—which the halakhah reads as monetary payment—and on the surface say the opposite: that there is no law of rodef. If so, how can one make a gezerah shavah from here? Perhaps the Gemara has some textual hint (it may be learned from another gezerah shavah to the verses I cited in Exodus, where it clearly concerns pursuit—though there it is not the combatants who pursue, but both of them vis-à-vis the pregnant woman). This requires further analysis.

[4] The Gemara goes on to discuss a case of monetary liability for one and capital liability for the other.

[5] From Rashi in Sanhedrin it appears that the permission to kill the pursuer is based on “saving him from sin.” According to that, one might say that even in mutual pursuit it is worthwhile to kill one of them, for although we will not gain a life, we will save the successful one from the sin of murder. After all, even in the asymmetric case, we do not “gain” a life: if we leave the pursuer, the pursued dies; if we kill the pursuer, he dies. Either way, one dies; the choice to kill the pursuer is based on saving him from sin. Note that a decision by lottery will in any case prevent the sin of murder, for either we killed the would-be murderer (the one who would have succeeded) or the victim.

But Rashi’s approach is very difficult for several reasons. For example, regarding a minor pursuer, the Amoraim dispute (Sanhedrin 72b), and the halakhah rules that he has the status of rodef and must be killed to save the pursued, even though a minor is not culpable for sin. It is thus clear that even for Rashi, saving from sin joins with the need to save the pursued; without the latter, we would not permit killing. Accordingly, even for Rashi, in mutual pursuit there is no logic to permit killing one of them.

[6] This parallels the Brisker Rav’s well-known analysis of the Rambam distinguishing two distinct components in the law of the pursuer: (1) an obligation to kill him; (2) the removal of his blood-status (“he has no blood”). See there for proofs and ramifications. My claim here is that in mutual pursuit only (2) applies, not (1).

[7] I have now seen a discussion in Rabbi Shabtai Rappaport’s article here (see notes 1 and 3). He also cites a responsum in Igrot Moshe, Yoreh De‘ah II §60.

[8] This is evident from the case of a minor pursuer, which, as noted, the halakhah rules may be killed. In the case of the fetus in the Mishnah in Ohalot, however, it would seem otherwise, for the newborn whose head has emerged is not considered a pursuer because “from Heaven he is being pursued”—nature created this situation; hence there is no pursuit. But in the Rambam the situation does appear as pursuit (a “quasi-pursuer”); elsewhere I explained that this is a weaker form of rodef, permitting killing the “pursuer” only if he is a fetus whose life-value is lesser. One must discuss conjoined twins who have already been born: if indeed this is a natural situation and there is no full rodef, then apparently there is no permission to kill either of them. Again, one must ask whether the law of rodef does not apply at all, or whether it applies but may not be implemented in practice.