Are the kosher-signs just signs, or are they reasons?
Rabbi Shmuel Wise
Reb Elchanan Wasserman in his Koveitz Shiurim (Chullin; letter 27) engages with this question as it pertains to the gemara’s discussion of Monday’s daf this week (Chullin 62b). R’ Pappa there rules that the “swamp-rooster” is among the non-kosher birds, but the “swamp-hen” is among the kosher birds. A trick to remember this, R’ Pappa offers, is to recall the halachah that a male Ammonite convert is prohibited to marry into the congregation, but a female Ammonite convert is permitted.
At first glance, it would appear that these two “swamp” birds are of the same species—yet somehow the male version of this species is on the non-kosher list and the female version goes on the kosher list. Tosofos here, however, rejects such a reading, pointing out that if they are of the same species then by definition the “swamp-rooster” was born of the “swamp-hen”—a kosher bird and since “anything that comes from something permitted is itself permitted,” the “swamp-rooster” should also be permitted. Rather, Tosofos explains, these two birds are of two different species, one kosher the other not.
Tosofos in Niddah (50b) however explains differently. Tosofos there suggests that the “swamp-rooster” and the “swamp-hen” are indeed of the same species. Yet the “swamp-rooster” specifically is not kosher because it lacks the kosher-signs of birds delineated in the mishnah on 59a. As to the rule which says, “what came from something kosher is itself kosher,” Tosofos there explains that that rule doesn’t apply to a creature that develops in an egg outside of the mother’s body (see there for further elaboration on this).
Tosofos in Niddah seems to make the astounding suggestion that the kosher-signs we are learning about in these dapim are not simply ways to refer to the species that are kosher but they themselves are what makes the animals kosher! Indeed, Reb Elchanan understands that this is the very point of contention between Tosofos here in Chullin and Tosofos there in Niddah: Tosofos here contends that the kosher-signs are nothing more than signs that point to certain species that are kosher. Thus, it is untenable that there would be a species with a non-kosher male version and kosher female version: it’s either a kosher species or a non-kosher species. Tosofos there in Niddah, on the other hand, understands that everything is about the signs: With the signs the individual animal in question is kosher; without them it is not. Hence, it’s entirely plausible to have a kosher and non-kosher animal within the same species.
The notion that the presence of the kosher-signs is what makes an animal kosher seems hard to reconcile with the plain understanding of the laws of the kosher animals. Consider: If everything revolved around the kosher-signs there should be no need for the Torah to mention any particular species. Why then does the Torah do so by the kosher animals and birds? In fact, when it comes to the kosher birds, the Torah doesn’t even mention the kosher-signs whatsoever and instead just lists the non-kosher birds! Evidently the Torah did in fact prohibit entire groups (species) of animals and the kosher-signs are merely a means of describing the groups of animals that are prohibited.
But what of the words of Tosofos in Niddah? Didn’t Tosofos there state regarding the swamp bird that only the male which lacks the kosher-signs is not kosher?
It could be suggested that Tosofos himself is struggling with this very issue when he raises the point that “what is born of something kosher is itself kosher.” Tosofos deals with this problem by suggesting that the “swamp-rooster” is not technically born of its mother (see above). Thus, Tosofos is arguing that in light of the facts that a) the “rooster hen” has different physical attributes than its female counterpart (that do not display the kosher signs) and b) it isn’t legally born of its mother, the halachah views it as a different species with respect to its kosherness. This would mean that Tosofos in Niddah agrees that the kosher-signs merely refer us to certain groups of kosher animals.