In Rashi D"H "Yered Mumcheh" it says that the diuk is that you have to have a specialist check the animal and you cannot do Haaramah. Then rashi D"H "Vi'im Lav," the second pshat (Iy Nami), says that the words Lo Yishchot really mean that one cannot do Haaramah since one can obviously not shecht the bichor because it is a Tam.
(a) If the first Rashi states that no Haaramah can be done, why do we need Lo Yishchot to tell us the same thing.
(b) Furthermore, how could a Haaramah be a valid one if its a Bichor Tam, where its obvious to everyone that you cannot shecht it?
(could Rashi possibly be talking about two different types of Haaramah?)
Avi Hoffman, Washington Heights, New York
(a) You asked, "If the first (Rashi) [Reisha] states that no Haaramah can be done, why do we need Lo Yishchot to tell us the same thing.
When Rashi (DH Lo Tzericha) writes that we know he cannot do Ha'aramah from the Reisha (since the Mumcheh must "do down" to see the animal"), he means that even without the Seifa (v'Im Lav...) we would know that Ha'aramah is not permitted. However, that does not mean that the Seifa is extra if it is only teaching the same thing as the Reisha (that Ha'aramah cannot be done). It is quite common for a Mishnah which teaches a Chidush "if such and such is done", to conclude that "if it is not done" the Chidush does not apply. This is an accepted stylistic method of the Mishnah; it will state both the positive and the negative, for clarity. (See for example Mishnah Berachos 2:1, 3:2, 7:5, etc.)
This is evident from our Sugya as well. The Gemara did not ask "why did the Mishnah have to state that if it has no Mum one should not bring up the animal (i.e., this is already evident from the Reisa)." It simply asks that the Mishnah should have said "Lo Ya'aleh v'Yishchot," since Lo Ya'aleh is the main Chidush.
The Rashi you asked about (DH v'Im Lav), then, is simply saying that with regard to the Beraisa, we are forced to accept the Dochek that "Lo Yishchot" really means "Lo Ya'aleh v'Yishchot." The Seifa is now simply stating the negative of the Reisha.
(b) You asked, "Furthermore, how could a Haaramah be a valid one if its a Bichor Tam, where its obvious to everyone that you cannot shecht it?"
The Bechor Tam of the Beraisa was only Tam when it fell into the Bor. Through the fall, it is very possible that it obtained a Mum. The Ha'aramah is to insist that it might have become a Ba'al Mum through the fall, and bring it up before showing it to a Mumcheh.