Gemara

34b (Rav Dimi): If one incurred a monetary obligation at the same time that he transgressed b'Shogeg a sin punishable by death or lashes (for Mezid), R. Yochanan says that he must pay, since he was not warned;

Reish Lakish exempts. Since if he was warned he would be exempt, he is exempt even if he was not warned.

Question: Surely, all agree that one who transgressed a capital sin b'Shogeg need not pay!

(Tana d'Vei Chizkiyah): "One who strikes an animal... and one who strikes (kills) a man" equates these. One who hits an animal pays, whether he was Shogeg or Mezid, whether or not he aimed for this animal, and whether he hit with an upward or downward motion. Likewise, one who strikes a man is exempt (from paying) in every case.

Correction (Ravin): Rather, if one transgressed a capital sin b'Shogeg, all agree that he does not pay. They argue about one who transgressed b'Shogeg a sin punishable by lashes and money;

R. Yochanan says that he pays. Only capital sins are equated (above, 3:i) to striking an animal (to exempt in every case). Chayavei Makos (punishable by lashes) are not equated.

Reish Lakish exempts from paying. The Torah explicitly equates Chayavei Makos to capital sins.

(Rava): We learn from a Gezeirah Shavah "Makeh-Makeh";

We do not need "so will be done to him" to teach about a blow worth a Prutah, so it teaches about blow worth less than a Prutah, which is punishable by lashes. While hitting him, he tore his silk. (The Gezeirah Shavah exempts him from paying for the silk.)

Question (Rav Chiya): Tana d'Vei Chizkiyah equated striking an animal and a man. How do we know that he hit the animal on a weekday, and always pays? Perhaps he hit it on Shabbos, and we distinguish (between Shogeg and Mezid)!

Answer (Rava): What is the case of "One who strikes an animal will pay for it, and one who strikes a man will die"? We must say that there was warning, for otherwise we would not kill one who struck a man!

If he struck the animal on Shabbos (with warning), he would not pay! Rather, we must say that he hit it on a weekday.

Pesachim 29a (Beraisa): If one ate Chametz of Hekdesh during Pesach, he was Mo'el;

Some say that he was not Mo'el.

(R. Yochanan): The Tana who exempts is R. Nechunya ben Hakanah, who exempts for (damage done while performing Melachah on) Yom Kipur (Chayavei Kerisos), just like for Shabbos (Chayavei Misas Beis Din).

Bava Kama 42a - Question: R. Yosi ha'Galili expounds "the owner of the ox is clean" to exempt paying for a fetus aborted due to one's animal (it gored the mother). Why didn't he learn like R. Akiva, from "when men will fight", not oxen?

Answer (Rav Ada bar Ahavah): When men fight, intending for each other, even if the woman dies, they pay (for the fetus). When they intend for her, they are exempt (if she dies). One might have thought that oxen are always liable.

A Beraisa supports Rav Ada.

Sanhedrin 78b (Mishnah): If one intended to kill a Nochri and (accidentally) killed a Yisrael, he is exempt;

R. Shimon says, even if he intended to kill Reuven and killed Shimon, he is exempt.

Chachamim exempt one who intended to kill a Nochri and killed a Yisrael. This implies that one who intended to kill Reuven and killed Shimon is liable.

R. Shimon expounds "V'Im Ason Yihyeh v'Nosata Nefesh Tachas Nafesh" to refer to paying money, like Rebbi;

(Beraisa - Rebbi): "V'Nosata Nefesh Tachas Nafesh" refers to money. It says 'Nesinah' here, like it says about paying for causing a miscarriage.

(Rava): Tana d'Vei Chizkiyah (above, 3:i) is not like Rebbi or Chachamim. He equates striking people and animals, whether or not he intended, whether he was Shogeg or Mezid;

This cannot mean without intention at all, for that is Shogeg! Rather, he intended for Reuven and killed Shimon. If we kill the murderer, we need not teach that he does not pay! Rather, he is not killed, and he does not pay.

Rishonim

Rambam (Hilchos Na'arah Me'orasah 1:13): If a man seduced or raped a woman for whom he is Chayav Misas Beis Din, whether or not he was warned he is exempt from the fine. "If there will be no Ason, he will pay" - whenever there is death, he does not pay, even though he killed the woman b'Shogeg. He did not intend for her, for it says "when men will fight..." This shows that regarding Ason, we do not distinguish between Shogeg and Mezid to exempt from paying. It says "one who strikes an animal", and "one who strikes a man". Just like one who hits an animal pays, whether he was Shogeg or Mezid, also one who strikes a man is exempt from paying whether he was Shogeg or Mezid.

Rambam (Hilchos Chovel u'Mazik 4:5): If one struck a pregnant woman and made her miscarry and she died, even if he was Shogeg he does not pay anything. "If there will be no Ason, he will pay" - whenever there is death, we do not distinguish between Shogeg and Mezid to exempt from paying.

Rambam (6): This is if he intended to hit her. If he intended to hit someone else, even if she died he pays for the fetus. Because he did not intend for her, this is like a matter without Misas Beis Din.

Rebuttal (Ra'avad): This is like R. Shimon, who exempts (from Misah) one who killed a different person than he intended for. But the Rambam himself rules like Chizkiyah, who exempts from payment regardless of intent!

Defense (Magid Mishneh): These two rulings do not depend on each other.

Rambam (7): If one wounded someone on Shabbos or wounded his parent, even if he was Shogeg he is exempt from paying. When one is Chayav Misas Beis Din, whether he was Shogeg or Mezid he is exempt from paying.

Question: How can R. Nechunya exempt due to the Kares for Chametz? The first Tana says that there was Me'ilah. This shows that he was Shogeg!

Answer #1 (Rashi Pesachim 29a DH Es): He was Mezid about Chametz, but Shogeg that it was Hekdesh.

Answer #2 (Tosfos DH Rebbi): The Halachah follows Chizkiyah, who exempts Chayavei Misos from payment even if he was Shogeg. Likewise, R. Nechunya exempts Chayavei Kerisos from payment even if he was Shogeg.

Poskim

Shulchan Aruch (CM 423:4): If one struck a pregnant woman and made her miscarry and she died, even if he was Shogeg he does not pay anything. "If there will be no Ason, he will pay." This is if he intended to hit her. If he intended to hit someone else, even if she died he pays for the fetus. Because he did not intend for her, this is like a matter without Misas Beis Din.

Rema: Some exempt even if he did not intend to hit her.

Beis Yosef (EH 177:4 DH v'Im Ba (2)): Rashi says that Chayavei Misos Shogegin is when he was not warned. The Rambam exempts from payment whether or not he was warned, and whether he was Shogeg or Mezid.