Talking Talmud

Do you need to see the entire process of shechitah to be able to trust that it was done properly? The Gemara has a case that does require one to see the entirety of the process, but we know that that isn't usually how it works (so often, we do not see any of the process of shechitah!), so the sages delve into the particulars of the case. Perhaps it's a question of whether you know the shochet's level of knowledge and expertise. Also, if one chooses an agent to go slaughter an animal and the agent discovers that the animal was already slaughtered - can it be trusted to be a kosher shechitah? What about terumah that was set aside? Would it have been set aside properly?

A quantifiable majority determines the outcome of an unknown, as per the biblical verse: "Follow the majority." But with an unquantifiable majority - what is the source for the principle to apply in those cases as well? Note that the Gemara supports this principle with 9 examples -- that is, 9 sources as possibilities from which it is understood or derived. Note also that checking the reality of the situation isn't the issue; the sages are intent on establishing the sources and using the majority to establish "truth," rather than looking for the truth in other ways.

Given that the knife for shechitah cannot be notched, there was an event when a knife was discovered to be notched after it was used to slaughter 13 animals. But if he only discovered that to be the case after the last animal's shechitah, then maybe it became notched along the process and the first animal(s) were not a problem. The big - and perhaps indeterminable - question is when did the knife received its notch? All of which leads to the conclusion that the knife must be checked (for notches and whatnot) before each and every act of shechitah. Also, investigating the source of "chazakah" (the given status of a thing unless or until proven otherwise). Beginning with the example of tzara'at, in the case of a house. But what if that tzara'at is behind the door? Or in a dark house? The question of whether there's a tzara'at lesion to find does not require spotlighting the whole house in the search! Note that the source of establishing a given is in the context of tzara'at, and not kashrut, but it's not the first time they are linked.

A Torah scholar must learn 3 skills: writing, kosher slaughtering, and circumcision. And 3 additional things are subject to dispute - whether they are skills that are required or commonplace: tying the knot of tefillin, the blessing for the wedding, and tying tzitzit. Also, standards of presumption regarding an animal: while it's alive, the presumption is that it's not going to be kosher. Once it's slaughtered correctly, then the presumption is that the animal IS kosher, unless a blemish is discovered. Also, what if a wolf bite is clear on the innards of an animal - but perhaps it's a puncture after the shechitah? Or might the bite have obscured a hole that would have made the animal a treyfa? What about a snake's poison? But the wolf/intestine is a concern of a prohibition! And the snake concern is about danger, which requires greater stringency!

If you heat a knife to white-hot, the shechitah done with that knife is kosher, because it was already sharp enough before it was hot. The concern is whether the slaughtering was done with the knife's blade or if it was done via the heat and a burn. The Gemara contrasts the issues that pertain here to the details of tzara'at, which has a long-standing tradition "halakhah le-Moshe mi-Sinai" regarding the measure of impurity. Plus the details of shechitah as applied to a case of tzara'at. Also, the 3 knives that the butcher needs to cut the meat and the forbidden fats, and to keep the forbidden from contaminating the permitted. Plus, distinctive indications regarding which knife was which.