Daf Yomi

Genetically Engineered Simanim

“A Bird with One Siman”

(Chulin 62a)

Genetic engineering is developing too fast for the following question to seem to be from another world: If signs of purity would grow on impure animals, would they be considered signs of purity? Those engaged in this field probably have not considered this question, but we who study Torah, mitzvos, and halacha must contemplate such new developments.

Do Simanim Identify or Render a Kosher Species?

The sugyos that occupy us now detail the signs of purity of land animals, birds, fish, and locusts. The question that draws our attention is whether signs of purity are merely simanim indicating their status or actually cause the kashrus status of the animals that bear them.

Let us ponder the following: On one hand, we can understand that Hashem determined that a dog is an impure species and that a bull is a kosher species, and that to identify them, He specified their signs in the Torah. On the other hand, we could also posit that Hashem determined that a dog is forbidden because it does not have the two signs of purity and that a bull is permitted because it bears both of them. The implication of this question is obvious. It would seem that if a sign of purity is merely a “sign,” then if there were a bull without those signs, it would still be permitted to eat because it is a kosher species, and conversely, if there were a dog with both signs of purity, it would still be forbidden to eat. If, however, the simanim of kashrus cause an animal to be pure, we could theoretically have a dog that may be eaten. We must divide this question into two separate parts: pertaining to animals born from the womb and animals hatched from eggs.

An Iron Rule

The Mishna at Bechoros 5:2 determines an iron rule: “That which comes from the impure is impure; that which comes from the kosher is kosher.” Therefore, if a cow bore a camel, it may be eaten as it came from a kosher animal (see the Gemara, ibid., where Rabbi Shimon forbids an impure species born of a kosher one). But if a camel bore a calf, it would be forbidden to eat it because it came from the non-kosher camel. Thus, we have a calf that came from an impure species that may not be eaten despite its signs of purity, and a camel born of a kosher species which is permitted despite the lack of signs of purity. We thus see that in these animals, the signs of purity were meant as an indication of purity, but do not cause purity.

Animals Hatched from Eggs

The issue remains, however, for animals hatched from eggs. They are not considered to be “coming” from the animal that laid the egg, as in the process of the egg becoming an animal, the egg first becomes like dust not fit to be eaten and life forms in it only afterwards (see Temurah 31a). We can therefore discuss, with regard to them, if their signs of purity are merely signs or perhaps actually the cause of their purity.

What’s Good for the Goose Is Not Good for the Gander

Rabbi Elchanan Wasserman, zt”l, also discusses this inquiry in his Kovetz Beiurim, Chulin 27, and, in his opinion, this is a difference of opinions among the Rishonim. Our sugya explains that there is a kind of chicken in which the male is impure and the female kosher. Tosafos explain (s.v. Tarnegulta) that we must say that the male and female do not belong to the same species although they seem to be, as it cannot be that the male is impure while the female is kosher.

However, elsewhere (Niddah 50b, s.v. Tarnegulta), Tosafos believe that such a situation could occur, as the female bears signs of purity but the male lacks them (see ibid., where they conclude that “it seems to be the main opinion that they are two species”). The main point of their disagreement, explains Rabbi Wasserman, lies in our inquiry. If the signs of purity were meant merely as an indication of the forbidden and permitted species, it cannot be that members of the same species would not have the same halachic status. But if the signs of purity are the cause of purity, it could be that the male, lacking signs of purity, is impure while the female is kosher.

Signs as a Testament

The Maharit in his Responsa 1:51 asserts that the signs of purity are merely “signs,” pointing out that all the signs in the Gemara do not have an essential quality but rather testify to the identity of those that bear them. After all, the signs of adulthood (bagrus) do not make the boy or girl mature but testify to their physical adulthood.

On the other hand, there are grounds to prove that the signs of purity are the cause of purity. After all, our Gemara (66b) explains that though there are no fish with scales without fins, the Torah did not suffice with merely mentioning the sign of the scales in order “to aggrandize the Torah.” This means (Ritva, Niddah 51a, and see Chazon Yechezkel, etc.) that the Torah wanted to emphasize that both of the signs cause the fish to be kosher. We thus see that the signs of purity are not merely signs but give kashrus to the animal which bears them.

Natural Signs of Purity

However, Rabbi Shlomo Zalman Auerbach, zt”l (Minchas Shlomo, II, at the end) mentions that we cannot prove anything from this Gemara as it could be that only signs of purity that appear naturally purify the animal, but not signs of purity that are unnatural to this species (see Chidushei Rabbeinu Chaim HaLevi, Hilchos Maachalos Asuros, 3:11).

We should mention that Tosafos’s conclusion (on our sugya and in Niddah 50b, s.v. Tarnegulta) indicates that the signs are merely an indication and not a cause.