parshas hachodesh; simanei kashrus - sibah or siman; achila less than k'zayis - ptur onshin or not a maaseh achila; and more

1) The gemara (Pesachim 6) has a din שואלין ודורשין בהלכות הפסח קודם הפסח שלשים יום which is derived from the fact that Moshe taught the halachos of Pesach Sheni one month in advance, on Pesach Rishon שהרי משה עומד בפסח ראשון ומזהיר על הפסח שני שנאמר ויעשו בני ישראל את הפסח במועדו וכתיב ויהי אנשים אשר היו טמאים לנפש אדם.  R' Chaim Kanievsky held that this is a real derasha, not just an asmachta, and is therefore a din d'orasya.  Rokeach writes that reading parshas Parah and HaChodesh is a kiyum of this din of being shoel v'doresh hil ha'chag, as the whole point of these parshiyos is to teach us the halachos of becoming tahor and offering korban pesach.  Acc to R' Chaim, the reading would therefore be a kiyum d'orasya.  Rama (282:4, see R' Akiva Eiger there) quotes a yesh omrim that a katan should not be called by for any of the 4 parshiyos.

I enjoyed posting the Ayeles haShachar pieces last week, so I am going to do more of the same this week, with a mix of halacha and aggadah.

2)  זֹאת הַחַיָּה אֲשֶׁר תֹּאכְלוּ -  מלמד שהיה משה אוחז בחיה ומראה אותה לישראל.  Why did Moshe have to hold up the animals for display?  What was the necessity of having a show and tell session instead of just teaching the halachos?

The Rogatchover has a chakira whether the simanei kashrus are a siman or a sibah for a creature's kashrus (see post here, also here ).  Tos (Nida 50b) writes with respect to some kind of wild chicken that lives by a pond:

 תרנגולתאדאגמא. הזכר אסור לפי שאין לו סימני טהרה ולא שרי מטעם כל היוצא מן הטהור טהור שהרי האם לא ילדה האפרוח אלא ביצים הטילה והאפרוח מעפרא קא גדיל ונאסר ממילא ע"י סימני טומאה ונקבה נמי אין לאוסרה למאן דאסר זה וזה גורם דהא אפרוח לא יצא אלא מן הביצה ומעפרא קגדיל כדפרישית.

Even though we know that this chicken is born from the egg of a kosher mother bird, it is considered a min tamei because it lacks simanim.  It seems from Tos that simanim are a sibah -- even though we know the family the bird is related to, it still needs simanim to be kosher.  Ralbag on our parsha seems to disagree and hold that simanin just serve to identify the species of the animal, and it's by virtue of being a member of that species that it is kosher.  

R' Shteinman suggests that our Rashi speaks to this issue.  Let's say a person could genetically engineer a tamei animal and cause it to be born with simanei kashrus, or genetically engineer a kosher animal so it was not born with simanim.  What would be its status -- tamei or tahor?  Are the simanim the sibah for the animal's status, and without them it is tamei, or are the simanim just a siman that help us identify the species?  R' Shteinman writes that Moshe held up each animal so that we can recognize it and know what species it is because that is what determines whether it is tamei or tahor, not the presence/absence of simanin.

Rashi works well l'shitaso, as he writes at the end of the parsha (11:47) writes that the mitzvah of knowing the simanei kashrus is לא בלבד השונה, אלא שתהא יודע ומכיר ובקי בהן.  Theoretical knowledge is not enough; you have to be able to recognize the physical signs of what makes an animal kosher.  

3) וְאֶת הַשָּׁפָן...וְאֶת הָאַרְנֶבֶת  For those interested in this sort of thing (which, for the record, I am not), R Shteinman quotes R' Hirsch who writes  והנה, רגילים לפרש ששפן וארנבת הם בעלי החיים הקרויים כן בימינו. אך פירוש זה לא ייתכן, אלא אם כן שני בעלי חיים אלה יהיו מעלי גרה, ודוחק לומר כן and then adds that today we know that the ארנבת actually does chew its cud, but it is almost undetectable.  (I'm not sure why this piece is in brackets.)  

4) Yesh lachkor whether אין אכילה פּחותה מכּזית means it is not a maaseh achila, or whether it is a maaseh achila but there is a ptur onshin? 

Rashi comments on the pasuk  וְהָאֹכֵל מִנִּבְלָתָהּ יְכַבֵּס בְּגָדָיו וְטָמֵא עַד הָעָרֶב וְהַנֹּשֵׂא אֶת נִבְלָתָהּ יְכַבֵּס בְּגָדָיו וְטָמֵא עַד הָעָרֶב that the reason the pasuk mentions eating is to tell us that the shiur of noge'a or nosei is the same amount as that which constitutes achila, namely, a k'zayis:

  האוכל – ליתן שיעור לנושא ולנוגע כדי אכילה, והוא כזית.

It sounds from here like the definition of achila is a k'zayis.  

However, R' Shteinman points out that the implication of there being a chiyuv for eating a chatzi shiur (according to R' Yochanan Yoma 74) is that the shiur k'zayis is a maaseh achila, just there is a ptur onshin.  If achila less than a shiur is not a maaseh aveira, then the sevara of "chazi l'itztarufei" makes no sense -- 0+0 is still 0.