Explanation: The Gemara in Chulin (34a) explains the reason because we find a Sheini can make a Sheini through liquid.

Question: Why does the Gemara (ibid.) need this reason? We should say that the reason a Sheini makes a Sheini is as explained in our Gemara later, as there are times that a person eats impure food and he will take Terumah liquids etc.!

Answer: It would look ridiculous to make one who eats a Sheini a Sheini due to the Gezeirah regarding Terumah, if not for the fact that we find a Sheini can make a Sheini (as stated in Chulin 34a).

Opinion: Rabeinu Tam says that whenever "Pesul Geviyah" (a person who is unfit to eat Terumah) is mentioned, such as in Eiruvin (82b) where it says, "And half of a half to make him unfit to eat Terumah" it is referring to an amount of (impure food that is the volume of) two eggs.

Opinion (cont.): (One should note that) According to the opinion that it is one and a half eggs (and certainly the opinion that it is two eggs), it is not the same decree being discussed in our Gemara, as according to the reasoning here even one egg should cause him to be unfit to eat Terumah. Rather, the decree (mentioned in Eiruvin ibid.) causing him to be unfit to eat Terumah is an early decree.

Opinion (cont.): They decreed this in order that people should not mistakenly say that just as it is permitted to eat Terumah after eating impure food even though the Terumah touches the impure food in his stomach, so too it is permitted to have Terumah touch impure food outside one's body. This is why they decreed that a person is unfit to eat Terumah if he eats a half Peras of impure food. However, they did not decree that he is impure if he merely touched the food.

Opinion (cont.): This is specifically regarding a half Peras (two eggs). However, regarding (food the size of) an egg one would not make this mistake, as a small amount of it remains between his teeth and therefore the amount is lessened before it gets to his stomach. Since the amount (where this is relevant) is certainly not an egg, the Rabbanan decreed that it only applies to a half Peras.

Opinion (cont.): However, the decree in our Gemara is indeed even if he touches the food and even regarding the size of an egg, due to the reasoning explained by the Gemara.

Proof: This (that a person becomes unfit to eat Terumah, see a1) is clearly an early decree, as in Yoma (80b) they thought to say that this manner of a person becoming unfit to eat Terumah is a Torah law. Everyone was expert in these eighteen decrees. If so, why would they mistakenly say that it is a Torah law, as this would lessen the eighteen decrees? (It must be that the decree that one who eats impure food becomes unfit to eat Terumah is an early decree.)

Implied Question: This is despite the fact that the liquid is a Rishon, as stated in Parah (8:7) that whatever causes Terumah to become impure causes liquid to become a Rishon. (They are not only unfit, but also become impure! Why does the Gemara merely say they will become unfit?)

Answer: Our Gemara says he makes it unfit because it was before the eighteen decrees when they decreed that liquid should be a Rishon, as I will explain.

Implied Question: The Gemara does not quote an explicit Mishnah in Yadayim (3:5) that says all holy writings cause the hands to become impure. (Why not quote a Mishnah instead of a Beraisa?)

Answer: This is because we can say that the Mishnah in Yadayim (ibid.) was specifically referring to Kodesh. This is why he quotes the Beraisa that explicitly states Terumah.

Question: Why quote hands being impure due to handling Sefarim in the name of Rebbi Parnach? This is true regarding everything that makes Terumah impure, as stated in Yadayim (3:2) that whatever causes Terumah to be unfit causes hands to become a Sheini!

Answer: This is specifically regarding Kodesh, similar to the law regarding a hand causing the other hand to become impure, which is only regarding Kodesh as is apparent from the Gemara in Chagigah (24b).

Implied Question: The Gemara in Chulin (34b) states that we find a Sheini makes a Sheini through liquid. It could also have said that we find a Sheini makes a Sheini through touching Sefarim. (Why didn't it give this example?)

Answer: Perhaps when he saw that Rebbi Eliezer did not accept his answer regarding liquids, he indeed answered from holy writings.

Question: The Mishnah in Yadayim (3:2) states that Rebbi Yehoshua says that an impure hand causes the other hand to become impure. They said to him etc. He said, we find holy writings etc. They said, one cannot judge Rabbinic laws from Torah laws...or from other Rabbinic laws (see Mishnah there).

Question (cont.): How can Rebbi Yehoshua bring proof from holy writings that are a Sheini and cause hands to be impure for Terumah to hands that only cause the other to become impure for Kodesh (and not for Terumah)?

Answer #1: He only wanted to rebut their logic that a Sheini does not make a Sheini.

Answer #2: Alternatively, one can explain that the case of holy writings mentioned in Yadayim (ibid.) is specifically regarding Kodesh, and is not the decree mentioned here by Rebbi Parnach that Yadayim due to a Sefer are impure.

Implied Question: The Gemara asks a question, "do the Rabbanan not agree that a person who eats food that is a Sheini is a Sheini" even though the Mishnah in Yadayim says that we do not judge Rabbinic laws from Torah laws or Rabbinic laws.

Answer: It appears that where there is a reason the Rabbanan will agree that a Sheini makes a Sheini, like the decree due to a Sefer quoted from Rebbi Parnach. They would also agree to the decree in our Gemara regarding one who eats food that is a Sheini, as our Gemara explained that a person might eat food that is impure, and put Terumah liquid in his mouth etc. (Tosfos Yeshanim)

Observation: The word, "even" implies that they first decreed that the Sefer had impurity, and afterward they decreed that Yadayim become impure if they touch Sefarim. Since they later decreed that all hands that one was not careful about are considered impure, as stated later, it must be that the decree regarding hands touching a Sefer was decreed on this day.

Question #1: They must have made this decree (hands touching a Sefer becoming impure) between the decree about the Sefer being impure and the hands that are not watched being impure. If so, there are more than eighteen decrees!

Answer: If we say that they did not make the decree regarding hands that touch a Sefer at this time, but rather much earlier, it would be understandable.

Question: However, the term, "even" does not imply that this is the case.

Question (cont.): Additionally, it is not possible that they made a decree regarding hands that touched a Sefer if a Sefer itself did not yet cause Terumah to become invalid!

Explanation: The Gemara somewhat implies that this does not refer specifically to a Sefer Torah, as the Mishnah in Yadayim (3:5) states that all holy writings cause the hands to become impure.

Explanation: If he holds it in order to read it, he receives no merit for learning at that time. If he touches it while rolling it (commonly known as "Gelilah"), he does not receive reward for doing so.

Question: There is a difference in a case when he touches a Sefer immediately after washing, and he did not take his mind away from ensuring his hands did not become impure. Even so, his hands would be considered impure due to Rebbi Parnach's law.

Answer: They would not have made a decree due to this case, as it is uncommon that a person will touch a Sefer immediately after washing his hands. However, now that a decree was originally made regarding hands touching a Sefer, they even made a decree regarding his touching it after washing his hands, as they did not differentiate between cases.

Explanation: This does not mean that Tevul Yom should be taken out of the Mishnah (Zavin 5:12), but rather that it was not one of the eighteen decrees.

Explanation: They cause impurity due to Torah law.

Observation: The Gemara's question therefore is according to Rebbi Akiva who holds in Pesachim (14b) that liquids that cause others to become impure is a Torah law.

Explanation: The Pasuk is referring to liquids that come from an impure vessel, and the Gemara derives liquids from a Sheretz using a Kal v'Chomer from liquids that come from a vessel.

Question: What is the question, "Isn't it is a Torah law?" Why don't we say that liquids that come from a Sheretz should not be more impure than those that come from an impure vessel which they are derived from, and therefore they should only be a Sheini? Food that touches these liquids should not cause Terumah to become invalid!

Answer: There is nothing that touches a Sheretz that does not turn into a Rishon. In Pesachim (14b), I explained this at length.

Question: Why is this decree necessary? Since they decreed that unwatched hands cause Terumah to become invalid, it follows that liquids that touch such hands are a Rishon. This is due to the rule, "whatever causes Terumah to become invalid causes liquids to become a Rishon!"

Answer: Food that becomes impure through liquids is due to the decree, "whatever causes Terumah to become invalid etc." which had not yet been decreed.

Implied Question: The Gemara says specifically, "liquids that are touched by hands." (Why didn't it say "things that invalidate Terumah?")

Answer: It includes everything that invalidate Terumah.

Implied Question: Rebbi Yehoshua answered Rebbi Eliezer in Chulin (34a) that we find that a Sheini makes a Sheini through liquid, even though the decree had not yet been made!

Answer: Their mindset was to make the decree imminently.

Implied Question: The Ri says that the Gemara could have said liquids that come from contact with unwatched hands, as they also cause a vessel to invalidate Terumah. (Why didn't it say this?)

Proof: This is as the Mishnah in Berachos (52a) states that Beis Shamai says one washes his hands and then pours the wine, as if he will pour the wine first the liquids on the back of the cup will be impure due to the hands, and they will make the cup impure.

Answer: Rather, it states liquids that come in contact with a Sheretz to teach that even these are only impure according to Rabbinic law.

Implied Question: The Gemara did not want to answer that Shamai and Hillel decreed regarding hands that touched a Sefer but not by unwatched hands. (Why not?)

Answer: This is because the terminology used is that they decreed impurity "on hands," implying all hands.

Question: Why don't we say that regarding three things they permanently argued, and regarding the eighteen decrees they argued but agreed by the next day?

Question (cont.): This would be similar to the Gemara's answer later when it asks regarding harvesting grapes in order to put them in a press etc. that Hillel was quiet when confronted by Shamai, and therefore it is not considered one of the three permanent arguments.

Answer: It is unlike harvesting grapes, as Hillel was quiet when confronted by Shamai and he admitted to him at that gathering. This is why it is not included. However, in our case where they argued the entire day and only agreed the next day, it should not have said, "they did not argue."

Implied Question: This is despite the fact that it is somewhat implied that Hillel and Shamai themselves were present on the day that the eighteen decrees were made.

Proof: This is apparent from the fact that the Gemara later (17a) says regarding harvesting for the press that on that day Hillel was bent over and sat before Shamai etc., and the same terminology is used in the Tosefta regarding the eighteen decrees.

Answer: Even so, it must be that these were two different incidents.