1)

(a)Our Mishnah lists four Avos Nezikin Shor, Bor, Mav'eh and Hev'er (which will all be explained shortly).

(b)'Avos Nezikin' are the principle categories of damage, all of which are mentioned by the Torah in Mishpatim.

(c)The Tana does not follow the same order as he does further on in the Mishnah 'Lo Harei ha'Shor k'Harei ha'Mav'eh ... ' because he prefers to follow the order in which they appear in the Torah (see Tosfos DH 'ha'Shor').

(d)Assuming 'Shor' to mean the damage of 'Regel', and Mav'eh, that of 'Shen', when the Tana says 'Lo Harei ha'Shor k'Harei ha'Mav'eh', he means that had the Torah only written 'Regel', we would not automatically have known 'Shen' from it (for reasons that will be explained later).

2)

(a)We need a Pasuk to teach us the obligation to pay of someone who ...

1. ... lights a fire, which we cannot learn from Shor and Mav'eh combined (the 'Tzad ha'Shaveh' [what they have in common]) since they possess a soul of life (which may be the reason that they are obligated to pay), whereas a fire does not.

2. ... digs a pit, which we cannot learn it from the combination of Shor, Mav'eh and Hev'er which all move (and enter the domain of the Nizak), whereas a Bor remains still (and it is the Nizak who enters the Mazik's domain).

(b)The two specifications that all four Avos have in common are that it is natural for them to damage and that the onus of guarding them against such a contingency lies on the person who will ultimately have to pay.

(c)Assuming that the Mazik pays with Karka, he is obligated to pay with the best quality ground.

(d)The Nizak cannot force the Mazik to pay Karka if he does now want to.

3)

(a)Where there are Avos, there must be Toldos. We also find Avos and Toldos in the areas of Shabbos and Tum'ah.

(b)There is no basic difference between the thirty-nine Avos and the Toldos regarding Shabbos, because in both regards one is Chayav a Chatas for a Shogeg, and Sekilah for transgressing b'Mezid.

(c)The Tana refers specifically to those thirty-nine as Avos and the rest as Toldos, according to ...

1. ... the Chachamim of Rebbi Eliezer to teach us that if someone contravenes an Av together with its Toldah in one He'elam (having forgotten that both are forbidden on Shabbos), one brings only one Chatas.

2. ... Rebbi Eliezer (who obligates two Chata'os in that case), because the thirty- nine Avos Melachos were considered major Melachos in the Mishkan, in which case .

4)

(a)A Sheretz, Shichvas-Zera (semen) and a Tamei Mes are all Avos ha'Tum'ah.

(b)In spite of the fact that a Tamei Mes is not an original source of Tum'ah, he is nevertheless an Av ha'Tum'ah because the corpse itself is an Avi Avos ha'Tum'ah.

(c)Toldos ha'Tum'ah differ from Avos inasmuch as they can only transmit Tum'ah to food and drink, whereas Avos render people and vessels Tamei as well.

(d)When they asked whether the Toldos of Nezikin follow the specifications of the Avos or not, Rav Papa gave a vague answer. He said some of them are and some of them are not.

5)

(a)The Tana of the Beraisa lists three Avos in 'Shor', Keren, Shen and Regel.

(b)From the Pasuk ...

1. ... in Melachim "Va'ya'as Lo Tzidkiyah ... Karnei Barzel, Va'yomer, Koh Amar Hash-m ... b'Eleh Tenagach Es Aram" he learns that when the Torah writes "Ki Yigach" (Negichah), it is referring to the horn.

2. ... in v'Zos ha'Berachah "Bechor Shoro Hadar lo, v'Karnei la'Hem Karnav, ba'Hem Amim Yenagach" that it is not only for damages performed by a detached horn that one pays for only half the damage the first three times (because it is unusual), but that the same applies to the damage performed by a horn that is attached (because it is unusual too).

(c)The initial suggestion is that 'Divrei Torah mi'Divrei Kabalah Lo Yalfinan' 'Divrei Kabalah' refers to Nevi'im and Kesuvim.

(d)We refute that suggestion however, on the grounds that learning a definition from a Pasuk in Nach falls under the category of a 'Giluy Milsa' (an indication) rather than a 'Yalfusa' (a real Limud, which is confined to Halachos).

6)

(a)Negifah, Neshichah, Revitzah and Be'itah are all Toldos of Keren. They are Chayav only if the animal performed these acts with the express intention of damaging the object, animal or person involved.

(b)Despite the fact that, in the same Parshah, the Torah also writes "Ki Yigof", Negifah is nevertheless not considered an Av because the Negifah in the Pasuk is synonymous with Negichah (as we shall now explain).

(c)By referring to Negichah (by Shor d'Azik Shor) with the Lashon "Ki Yigof" (which implies a less forceful action), the Torah implies that a person has a Mazal (a sixth sense that makes him afraid of oxen and therefore more elusive, making it more difficult for the ox to get him; or a protective angel, that forces the ox to use more force to kill him), whereas an animal does not.

(d)The ramifications of this distinction are that when the ox is Mu'ad (duly warned after killing three times, obligating to pay full damages) for killing a person, it is automatically Mu'ad for killing an animal, but not vice-versa.

7)

(a)What makes ...

1. ... Neshichah a Toldah of Keren and not of Shen is the fact that by 'Shen', the animal derives benefit from its damage, whereas by Neshichah, it does not.

2. ... Be'itah and Revitzah Toldos of Keren and not of Regel is the fact that Regel is common, whereas they are not.

(b)We reject the proposal that Rav Papa's 'Toldoseihen Lav k'Yotzei Bahen' refers to the Toldos of Keren on the grounds that they, like Keren, are 'Kavanaso La'hazik (the animal intends to damage), Mamoncha (your property) u'Shemirasan Alecha' (the onus is on you to guard them)'. Consequently, there is no logical reason to differentiate between the Av and the Toldos.

(c)So we switch to Shen v'Regel. Bearing in mind that the Torah writes "v'Shilach Es Be'iro u'Bi'er bi'S'deh Acher", we learn from the Pasuk ...

1. ... in Yeshayah "Meshalchei Regel ha'Shor v'ha'Chamor" that "v'Shilach" refers to Regel.

2. ... in Melachim "Ka'asher Yeva'er ha'Galal ad Tumo" that "u'Bi'er" refers to Shen.

(d)In the previous Pasuk, Shen is referred to as "Galal" either because it is sometimes revealed or because by means of the tooth, the food is reduced to excrement (which "Galal" can also mean).