Niddah 23a

וְיָלְפִינַן מוּפְנָה מִשְּׁנֵי צְדָדִין. וּלְהָכִי אַפְנְיֵהּ רַחֲמָנָא לִבְהֵמָה מִשְּׁנֵי צְדָדִין, כִּי הֵיכִי דְּלָא נִגְמַר מִן מוּפְנָה מִצַּד אֶחָד.

and derive the halakha from the analogy that is free on both sides. And it is for this reason that the Merciful One rendered the verbal analogy between animal and man free on both sides, so that one would not derive the halakha from the verbal analogy between sea monster and man, which is free on only one side.

רַב אַחָא בְּרֵיהּ דְּרָבָא מַתְנֵי לַהּ מִשְּׁמֵיהּ דְּרַבִּי אֶלְעָזָר לְקוּלָּא: כׇּל גְּזֵרָה שָׁוָה שֶׁאֵינָהּ מוּפְנָה כׇּל עִיקָּר — לְמֵדִין וּמְשִׁיבִין, מוּפְנָה מִצַּד אֶחָד — לְרַבִּי יִשְׁמָעֵאל לְמֵדִין וְאֵין מְשִׁיבִין, לְרַבָּנַן לְמֵדִין וּמְשִׁיבִין, מוּפְנָה מִשְּׁנֵי צְדָדִין — דִּבְרֵי הַכֹּל לְמֵדִין וְאֵין מְשִׁיבִין.

Rav Aḥa, son of Rava, teaches in the name of Rabbi Elazar a more lenient version of the aforementioned principle of exegesis of verbal analogy: With regard to any verbal analogy that is not free at all, one can derive halakhot from it, but one can also refute it logically. If the verbal analogy is free on one side, according to Rabbi Yishmael one can derive halakhot from it, and one cannot refute it. According to the Rabbis, one can derive halakhot from it, but one can also refute it. If the verbal analogy is free on both sides, everyone agrees that one can derive halakhot from it and one cannot refute it.

וּלְרַבָּנַן, מַאי אִיכָּא בֵּין מוּפְנָה מִצַּד אֶחָד לְשֶׁאֵינָהּ מוּפְנָה כׇּל עִיקָּר?

The Gemara asks: But if so, according to the Rabbis, what difference is there between a verbal analogy that is free on one side and one that is not free at all? In both cases, the Rabbis hold that one can derive halakhot from such a verbal analogy but one can also refute it.

נָפְקָא מִינַּהּ הֵיכָא דְּמַשְׁכַּחַתְּ לַהּ מוּפְנָה מִצַּד אֶחָד, וְשֶׁאֵינָהּ מוּפְנָה כׇּל עִיקָּר, וְלָאו לְהַאי אִית לֵיהּ פִּירְכָא, וְלָאו לְהַאי אִית לֵיהּ פִּירְכָא — שָׁבְקִינַן שֶׁאֵינָהּ מוּפְנָה כׇּל עִיקָּר, וְגָמְרִינַן מִמּוּפְנָה מִצַּד אֶחָד.

The Gemara answers: The difference is in a case where you find two mutually exclusive verbal analogies, one that is free on one side and one that is not free at all, and neither does this one have a logical refutation nor does that one have a logical refutation. In such a case, we disregard the analogy that is not free at all, and we derive the halakha from the one that is free on one side.

וְהָכָא, מַאי פִּירְכָא אִיכָּא? מִשּׁוּם דְּאִיכָּא לְמִיפְרַךְ: מָה לְאָדָם, שֶׁכֵּן מִטַּמֵּא מֵחַיִּים.

The Gemara asks: And here, with regard to the verbal analogy between man and sea monster, which was rejected because it is free on only one side, what logical refutation is there on account of which this verbal analogy is rejected? The Gemara answers: The verbal analogy between man and sea monster is rejected because it can be refuted as follows: What is unique about man? Man is unique in that a person can become impure while he is alive, unlike an animal, which can become impure only after it dies, or a sea monster, which cannot become impure at all.

וְכֵן אָמַר רַבִּי חִיָּיא בַּר אַבָּא אָמַר רַבִּי יוֹחָנָן: הַיְינוּ טַעְמָא דְּרַבִּי מֵאִיר — הוֹאִיל וְנֶאֶמְרָה בּוֹ ״יְצִירָה״ כְּאָדָם.

And likewise, Rabbi Ḥiyya bar Abba said that Rabbi Yoḥanan said: This is the reason for the opinion of Rabbi Meir, that a woman who discharges an item similar to a domesticated animal, an undomesticated animal, or a bird is impure: It is because formation is stated with regard to the creation of these animals, just as it is stated with regard to the creation of man.

אֲמַר לֵיהּ רַבִּי אַמֵּי: אֶלָּא מֵעַתָּה הַמַּפֶּלֶת דְּמוּת הַר — אִמּוֹ טְמֵאָה לֵידָה, שֶׁנֶּאֱמַר ״כִּי הִנֵּה יוֹצֵר הָרִים וּבוֹרֵא רוּחַ״? אֲמַר לֵיהּ: הַר מִי קָא מַפְּלָה? אֶבֶן הִיא דְּקָא מַפְּלָה, הָהוּא ״גּוּשׁ״ אִיקְּרִי.

Rabbi Ami said to him: If that is so, then in the case of a woman who discharges an item that has the shape of a mountain, its mother should be impure with the impurity of a woman after childbirth, as it is stated with regard to the creation of mountains: “For He Who forms the mountains and creates the wind” (Amos 4:13). Rabbi Ḥiyya bar Abba said to him: Does she discharge a mountain? The discharged item cannot possibly be that large. It is an item with the form of a stone that she discharges, and that is called a clod, not a mountain.

אֶלָּא מֵעַתָּה הַמַּפֶּלֶת רוּחַ — תְּהֵא אִמּוֹ טְמֵאָה לֵידָה, הוֹאִיל וְנֶאֶמְרָה בּוֹ ״בְּרִיאָה״ כְּאָדָם, דִּכְתִיב ״וּבוֹרֵא רוּחַ״? וְכִי תֵימָא לֹא מוּפְנֶה, מִדַּהֲוָה לֵיהּ לְמִכְתַּב ״יוֹצֵר הָרִים וְרוּחַ״, וּכְתִיב ״וּבוֹרֵא רוּחַ״, שְׁמַע מִינַּהּ לְאַפְנוֹיֵי!

Rabbi Ami further inquired: If that is so, in the case of a woman who discharges an item having an amorphous form [ ruaḥ ], its mother should be impure with the impurity of a woman after childbirth, since creation is stated with regard to it, just as it is stated with regard to man, as it is written: “And creates the wind [ ruaḥ ].” And if you would say that no verbal analogy can be drawn here, because the verse is not free, i.e., it is not superfluous, as it is necessary to recount the creation of the wind, that is not so. Rabbi Ami explains: From the fact that the verse could have written: Who forms the mountains and the wind, and instead it is written: “Who forms the mountains and creates the wind,” conclude from it that the superfluous word “creates” serves to render it free for drawing a verbal analogy between ruaḥ and man.

אֲמַר לֵיהּ: דָּנִין דִבְרֵי תוֹרָה מִדִּבְרֵי תוֹרָה, וְאֵין דָּנִין דִבְרֵי תוֹרָה מִדִּבְרֵי קַבָּלָה.

Rabbi Ḥiyya bar Abba said to Rabbi Ami: One derives matters that are stated in the Torah from matters that are stated in the Torah, i.e., from verses in the Torah, but one does not derive matters that are stated in the Torah from the words of the tradition, i.e., verses in the Prophets or the Writings, such as the verse in Amos.

(אָמַר) רַבָּה בַּר בַּר חַנָּה, אָמַר רַבִּי יוֹחָנָן: הַיְינוּ טַעְמָא דְּרַבִּי מֵאִיר — הוֹאִיל וְעֵינֵיהֶם דּוֹמוֹת כְּשֶׁל אָדָם.

§ Rabba bar bar Ḥana said that Rabbi Yoḥanan said: This is the reason for the opinion of Rabbi Meir: Since the eyes of these animals are similar to those of a human, a woman who discharges an item of that type is impure.

אֶלָּא מֵעַתָּה, הַמַּפֶּלֶת דְּמוּת נָחָשׁ תְּהֵא אִמּוֹ טְמֵאָה לֵידָה, הוֹאִיל וְגַלְגַּל עֵינוֹ עָגוֹלה כְּשֶׁל אָדָם! וְכִי תֵימָא הָכִי נָמֵי, לִיתְנֵי נָחָשׁ!

The Gemara objects: If that is so, then in the case of a woman who discharges an item that has the form of a snake, its mother should likewise be impure with the impurity of a woman after childbirth, since the pupil of a snake is round, like that of a human. And if you would say that indeed, this is the halakha , then let the mishna teach this case of a woman who discharges an item that has the form of a snake among the other cases where the woman discharges an item of an unusual form.

אִי תְּנָא נָחָשׁ, הֲוָה אָמֵינָא: בְּנָחָשׁ הוּא דִּפְלִיגִי רַבָּנַן עֲלֵיהּ דְּרַבִּי מֵאִיר, דְּלָא כְּתִיב בֵּיהּ ״יְצִירָה״, אֲבָל בְּהֵמָה וְחַיָּה — לָא פְּלִיגִי, דִּכְתִיבָא (ביה) [בְּיהוּ] ״יְצִירָה״.

The Gemara explains: If the mishna had taught the case of a snake, I would say that it is only in the case of a woman who discharges an item having the form of a snake that the Rabbis disagree with Rabbi Meir and rule that the woman is not impure, as a term of formation is not written with regard to the creation of the snake. But with regard to a woman who discharges an item having the form of a domesticated animal or an undomesticated animal, they do not disagree with Rabbi Meir, as the concept of formation is written with regard to them.

וְהָא גַּבֵּי מוּמִין קָתָנֵי לַהּ: אֶת שֶׁגַּלְגַּל עֵינוֹ עָגוֹל כְּשֶׁל אָדָם! לָא קַשְׁיָא — הָא בְּאוּכָּמָא, הָא בְּצִירְיָא.

The Gemara raises a difficulty: But with regard to the halakhot of blemishes that render the slaughter of a firstborn animal permitted, it is taught in a mishna ( Bekhorot 40a) that an animal whose pupil is round like that of a human is considered blemished. Evidently, the eyes of animals are dissimilar to those of humans. The Gemara answers that it is not difficult; this statement, that the eyes of animals are similar to those of humans, is referring to the pupil, and that statement, that the eyes of animals are not similar to those of humans, is referring to the entire eyeball in the socket.

רַבִּי יַנַּאי אָמַר: הַיְינוּ טַעְמָא דְּרַבִּי מֵאִיר — הוֹאִיל וְעֵינֵיהֶם הוֹלְכוֹת לִפְנֵיהֶם כְּשֶׁל אָדָם. וַהֲרֵי עוֹף, דְּאֵין עֵינָיו הוֹלְכוֹת לְפָנָיו, וְקָאָמַר רַבִּי מֵאִיר דְּטָמֵא! אָמַר אַבָּיֵי: בְּקַרְיָא וְקִיפוֹפָא, וּבִשְׁאָר עוֹפוֹת — לָא.

§ Rabbi Yannai said: This is the reason for the opinion of Rabbi Meir: It is because the eyes of these animals are fixed in the front of their heads like those of a human, unlike the eyes of birds and snakes, a woman who discharges an item of that kind is impure. The Gemara raises a difficulty: But there is the case of a woman who discharges an item similar to a bird, whose eyes are not fixed in the front of its head, and nevertheless Rabbi Meir says that the woman is impure. This apparently contradicts Rabbi Yannai’s explanation. Abaye said: Rabbi Meir is referring to the little owl [ bekarya ] and the great owl [ vekifofa ], whose eyes are fixed in the front of their heads, but in the case of a woman who discharges any of the other species of birds, Rabbi Meir does not deem her impure.

מֵיתִיבִי: רַבִּי חֲנִינָא בֶּן אַנְטִיגְנוֹס אוֹמֵר: נִרְאִין דִּבְרֵי רַבִּי מֵאִיר בִּבְהֵמָה וְחַיָּה, וְדִבְרֵי חֲכָמִים בְּעוֹפוֹת.

The Gemara raises an objection to this answer from a baraita : Rabbi Ḥanina ben Antigonus says: The statement of Rabbi Meir seems correct in the case of a woman who discharges the form of a domesticated animal or an undomesticated animal, and the statement of the Rabbis seems correct in the case of birds.

מַאי עוֹפוֹת? אִילֵּימָא בְּקַרְיָא וְקִיפוֹפָא, מַאי שְׁנָא בְּהֵמָה וְחַיָּה דְּעֵינֵיהֶן הוֹלְכוֹת לִפְנֵיהֶן כְּשֶׁל אָדָם? קַרְיָא וְקִיפוֹפָא נָמֵי!

The Gemara asks: To what birds is Rabbi Ḥanina ben Antigonus referring? If we say he is referring to the little owl and the great owl, what is the difference between this case and the cases of a domesticated animal or an undomesticated animal, with regard to which Rabbi Ḥanina ben Antigonus accepts the opinion of Rabbi Meir? If the key factor is that their eyes are fixed in the front of their heads like those of a human, Rabbi Ḥanina ben Antigonus should accept the opinion of Rabbi Meir in the case of a little owl or a great owl as well, as their eyes are also fixed in the front of their heads.

אֶלָּא פְּשִׁיטָא בִּשְׁאָר עוֹפוֹת. מִכְּלָל דְּרַבִּי מֵאִיר פְּלִיג בִּשְׁאָר עוֹפוֹת!

Rather, it is obvious that when Rabbi Ḥanina ben Antigonus says that he does not accept the opinion of Rabbi Meir, he is referring to the other species of birds. From the fact that it is necessary for Rabbi Ḥanina ben Antigonus to reject Rabbi Meir’s opinion in those cases, it may be concluded that Rabbi Meir himself disagrees with the Rabbis with regard to the other species of birds as well, despite the fact that their eyes are not fixed in the front of their heads.

חַסּוֹרֵי מִיחַסְּרָא וְהָכִי קָתָנֵי: רַבִּי חֲנִינָא בֶּן אַנְטִיגְנוֹס אוֹמֵר — נִרְאִין דִּבְרֵי רַבִּי מֵאִיר בִּבְהֵמָה וְחַיָּה, וְהוּא הַדִּין לְקַרְיָא וְקִיפוֹפָא, וְדִבְרֵי חֲכָמִים בִּשְׁאָר עוֹפוֹת, שֶׁאַף רַבִּי מֵאִיר לֹא נֶחְלַק עִמָּהֶם אֶלָּא בְּקַרְיָא וְקִיפוֹפָא, אֲבָל בִּשְׁאָר עוֹפוֹת — מוֹדֵי לְהוּ.

The Gemara explains that the baraita is incomplete, and this is what it is teaching: Rabbi Ḥanina ben Antigonus says: The statement of Rabbi Meir seems correct in the case of a domesticated animal or an undomesticated animal, and the same is true with regard to a little owl or a great owl. And the statement of the Rabbis appears correct even to Rabbi Meir with regard to the other species of birds. The reason is that even Rabbi Meir agrees that if a woman discharges an item that has the form of one of the other species of birds, she is not impure, i.e., he disagrees with them only with regard to a little owl or a great owl, but he concedes to their opinion with regard to the other species of birds.

וְהָתַנְיָא: אָמַר רַבִּי אֶלְעָזָר בְּרַבִּי צָדוֹק: הַמַּפֶּלֶת מִין בְּהֵמָה וְחַיָּה, לְדִבְרֵי רַבִּי מֵאִיר — וָלָד, וּלְדִבְרֵי חֲכָמִים — אֵינוֹ וָלָד. בְּעוֹפוֹת — תִּיבָּדֵק.

The Gemara cites proof for Abaye’s claim that Rabbi Meir differentiates between an owl and other species of birds, as it is taught in a baraita that Rabbi Elazar, son of Rabbi Tzadok, says: In the case of a woman who discharges an item that has the form of a type of domesticated animal or undomesticated animal, according to the statement of Rabbi Meir it has the halakhic status of a full-fledged offspring, and according to the statement of the Rabbis, it does not have the status of a full-fledged offspring. In the case of a woman who discharges an item that has the form of birds, it must be examined.

לְמַאן תִּיבָּדֵק? לָאו לְדִבְרֵי רַבִּי מֵאִיר, דְּאָמַר: קַרְיָא וְקִיפוֹפָא — אִין, שְׁאָר עוֹפוֹת — לָא?

The Gemara asks: According to whom must it be examined? Is this not referring to the statement of Rabbi Meir, who said that if a woman discharges an item that has the form of a little owl or a great owl, yes, she is impure, but if she discharges an item that has the form of other birds, she is not impure? Consequently, the item must be examined to determine what type of bird it resembles.

אָמַר רַב אַחָא בְּרֵיהּ דְּרַב אִיקָא: לָא, תִּיבָּדֵק לְרַבָּנַן, דְּאָמְרִי: קַרְיָא וְקִיפוֹפָא — אִין, שְׁאָר עוֹפוֹת — לָא.

Rav Aḥa, son of Rav Ika, said: No, this baraita does not prove that Rabbi Meir differentiates between owls and other species of birds, as perhaps the statement that the discharged item must be examined applies according to the Rabbis, as they say that if a woman discharges an item that has the form of a little owl or a great owl, yes, she is impure, but if a woman discharges an item that has the form of other birds, she is not impure.

וּמַאי שְׁנָא קַרְיָא וְקִיפוֹפָא מִבְּהֵמָה וְחַיָּה? הוֹאִיל וְיֵשׁ לָהֶן לְסָתוֹת כְּאָדָם.

The Gemara asks: But if the Rabbis hold that a woman who discharges an item similar to a land animal is not impure, why would they hold that if she discharges an item that has the form of owls she is impure? What is the difference between a little owl and a great owl on the one hand, and a domesticated animal and an undomesticated animal on the other? The Gemara answers: Since owls have cheeks like those of a human, therefore a woman who discharges an item similar to an owl is impure, whereas if she discharges an item that has the form of a land animal she is pure, despite the fact that their eyes are fixed in the front of their heads.

בְּעָא מִינֵּיהּ רַבִּי יִרְמְיָה מֵרַבִּי זֵירָא: לְרַבִּי מֵאִיר דְּאָמַר בְּהֵמָה בִּמְעֵי אִשָּׁה וָלָד מְעַלְּיָא הוּא, קִבֵּל בָּהּ אָבִיהָ קִידּוּשִׁין מַהוּ? לְמַאי נָפְקָא מִינַּהּ? לְאִיתְּסוֹרֵי בַּאֲחוֹתָהּ.

§ Rabbi Yirmeya asked Rabbi Zeira: According to Rabbi Meir, who said that an animal in the womb of a woman is considered a full-fledged offspring, what is the halakha in a case where it is a female, and her father accepted betrothal for her, i.e., he married her off by accepting betrothal money from a man, or a document of betrothal? Is such a betrothal valid? Rabbi Yirmeya elaborated: What practical difference is there whether it is valid? The difference is with regard to whether it is prohibited for the man to marry her sister. If the betrothal is valid, it is prohibited for the husband to marry her sister, as one may not marry his wife’s sister.

לְמֵימְרָא דְּחָיֵי? וְהָאָמַר רַב יְהוּדָה אָמַר רַב: לֹא אֲמָרָהּ רַבִּי מֵאִיר אֶלָּא הוֹאִיל וּבְמִינוֹ מִתְקַיֵּים! אָמַר רַב אַחָא בַּר יַעֲקֹב: עַד כָּאן הֱבִיאוֹ רַבִּי יִרְמְיָה לְרַבִּי זֵירָא לִידֵי גִּיחוּךְ, וְלֹא גִּחֵיךְ.

The Gemara asks: Is this to say that such an offspring can live? This factor is important, as a man is prohibited from marrying his wife’s sister only during his wife’s lifetime. But doesn’t Rav Yehuda say that Rav says: Rabbi Meir said that a woman who discharges an item that has the form of an animal is impure only since there are other animals of its type that can live, i.e., there are animals similar to the discharged item that do survive, but not that creature itself. Rav Aḥa bar Ya’akov says: Rabbi Yirmeya tried this hard to cause Rabbi Zeira to laugh, but he did not laugh. In other words, Rabbi Yirmeya was not asking his question seriously.

גּוּפָא, אָמַר רַב יְהוּדָה אָמַר רַב: לֹא אֲמָרָהּ רַבִּי מֵאִיר אֶלָּא הוֹאִיל וּבְמִינוֹ מִתְקַיֵּים. אָמַר רַב יִרְמְיָה מִדִּפְתִּי:

The Gemara discusses the matter itself. Rav Yehuda says that Rav says: Rabbi Meir said that a woman who discharges an item that has the form of an animal is impure only since there are animals of its type that can live. Rav Yirmeya of Difti says: