Please note that unless otherwise indicated, we follow the explanation of Rashi. Consequently, our notes and comments do not necessarily have any bearing on the practical Halachah.

1)

(a) There are four Avos Nezikin - Shor, Bor, Mav'eh and Hev'er (which will be explained later).

(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 ke'Hrei ha'Mav'eh ... ' - because it prefers to follow the order in which they appear in the Torah (see Tosfos DH 'hya'Shor').

(d) Assuming 'Shor' to mean the damage of 'Regel', and Mav'eh, that of 'Shen', when the Tana says 'Lo Harei ha'Shor ke'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).

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

1. ... lights a fire. We cannot learn it from Shor and Mav'eh - 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. We cannot learn it from 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) He is not obligated to pay with Karka - even if the Nizak asks for it, umless he chooses to do so.

(a) Where there are Avos, there must be Toldos. We also find this distinction - 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 be'Meizid.

(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.

4)

(a) What a Sheretz, Shichvas-Zera (semen) and a Tamei Meis have in common is - that they are all Avos ha'Tum'ah.

(b) In spite of the fact that a Tamei Meis is not a source, 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 aren't.

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

(b) From the Pasuk ...

1. ... "Va'ya'as Lo Tzidkiyah ... Karnei Barzel, Va'yomer, Koh Amar Hashem ... be'Eileh *Tenagach* es Aram" - he learns that when the Torah writes "Ki Yigach" (Negichah), it is referring to the horn.
2. ... "Bechor Shoro Hadar Lo, ve'Karnei Lahem Karnav, Bahem 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).

(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 de'Azik Shor) with the Lashon "Ki Yigof" (which implies a less forceful action), the Torah implies - that a person has a Mazel (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.

(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 doesn't.
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 La'av ke'Yotze 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 ve'Regel. Bearing in mind that the Torah writes "*ve'Shilach* es Be'iro *u'Bi'er* bi'S'deh Acher", we learn from the Pasuk ...

1. ... "*Meshalchei Regel* ha'Shor ve'ha'Chamor" - that "ve'Shilach" refers to Regel.
2. ... "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).