Explanation: The Ri says that the reason we do not follow the majority regarding Piku'ach Nefesh is because it says "va'Chai Bahem" (one should live through Mitzvos), and not die through them.

Mitzvos should never lead to death of a Yisrael.

Implied question: Why couldn't we have said [that when most are Nochrim, we assume that he is a Nochri] not to sustain him?

Answer: Even if it is half-half, one need not sustain him. Only when the majority are Yisrael, we say "this is only to sustain him."

Implied question: Why couldn't we have said [that when most are Yisrael, we assume that he is a Yisrael] to sustain him, like Rav said above?

Answer #1 (Rashi here): This answer is for Shmuel, who holds that we do not follow the majority even to excavate him from a fallen house, and all the more so to sustain him.

Implied question: Shmuel holds that we do not follow the majority regarding monetary laws! (Therefore, he would not follow the majority to return an Aveidah.)

Answer: That is only when he received it with the owner's permission, e.g. he sold an ox and it was found to be a gorer;

Here, he did not receive it with the owner's permission. We follow the majority.

Answer #2 (Rashi in Kesuvos 15b): It is a Chidush that we even return an Aveidah to him, which is a great Aveirah [if he is a Nochri];

We say (Sanhedrin 76b) that it says about one who returns an Aveidah to a Nochri "Lema'an Sefos ha'Ravah Es ha'Tzeme'ah." Even so, we return when the majority are Yisre'elim.

All the more so we sustain him. This is not such an Aveirah [if he is a Nochri], for we provide for poor Nochrim with poor Yisre'elim, due to Darchei Shalom.

Inference: If it is half-half, one does not return his Aveidah. The finder says "prove that you are a Yisrael, and [then] I will return to you."

Question: We could have said that all of the cases (the majority are Yisre'elim, Nochrim, or it is half-half) are relevant for damages!

If the majority are Yisre'elim, he is a Yisrael. This teaches about when our ox gored his ox. (We must pay him.)

If it is half-half, he is a Yisrael. This teaches about when his [Tam] ox gored our ox. He pays only half.

If the majority are Nochrim, he is a Nochri. He pays full damage.

Answer: The Gemara preferred to teach a Chidush in every case.

Question #1 (R. Tam): In Nidah (25a), a Beraisa asks "what is a Shefir Merukam (the outer skin of a fetus before bones form, with a human form inside)", and Aba Sha'ul says that its initial formation is mi'Rosho (from the head).

Question #2 (R. Tam): There, the Gemara connotes that we discuss only the size of the limbs, like it concludes "its two eyes are the size of eyes of a fly..."

Conclusion (R. Tam): The text [there] should say "Aba Sha'ul says that its initial formation is k'Rashon."

Explanation: On the day that its initial formation is finished, it is the size of Sal'am (a kind of grasshopper - Vayikra 11:22); the Targum of Sal'am is Reshona.

Support: Also the Aruch (Erech Rashon) explains like this.

Question: We could have answered that Misah and Yom Kipur atone with Teshuvah for all Aveiros in the Torah, but without Teshuvah, there are some Aveiros for which they do not atone, e.g. for Porek Ol (casting off the yoke), Megaleh Panim (distorting Torah) and annulling Bris Milah!

Answer #1: The Gemara gave a better answer.

Answer #2: Presumably, this is like the Seifa, which says that Teshuvah suspends [punishment] for severe Aveiros, until Yom Kipur comes and atones;

The Seifa refers to any [Maharsha - severe] Aveirah. Teshuvah does not atone without Yom Kipur. The same applies to the Reisha.

Source: In Shevu'os (13a), we learn this from a verse;

Citation (13a): "Ki Devar Hash-m Bazah" refers to Porek Ol and Megaleh Panim b'Torah. "V'Es Mitzvaso Hefar" is annulling Bris of the flesh;

Citation (cont.): It says "Hikares Tikares" - Hikares before Yom Kipur, Tikares after Yom Kipur.

Citation (cont.) Suggestion: Perhaps this is even if he did Teshuvah!

Citation (cont.) Rejection: "Avonah Bah" - it is only when the sin is still in him.

Question (R. Yakov of Orlins): Why aren't these among the 36 Kerisos listed in Kerisus 2a?