BS”D

Sukkah 15a-b

Teves 28, 5781. January 13, 2021

Some brief notes. 

1- Our Mishna states that 50% of Kosher סכך and 50% of פסול סכך  validates a Sukkah.  This, despite  the general rule is that סכך needs to be  more shade than the sunlight.

How do these two concepts jive?

This הלכה opens up two vast topics that are called ש”ס סוגיות, where we find intricate discussions concerning various scenarios in multiple places in ש”ס. 

Topic #1. 

When the Torah requires one to perform an action we assume that doing just רוב, a mere majority of it, is considered as “done”. 

[Obviously, not when the Torah states a measurement. Such as eating a כזית of מצה. Eating רוב of a כזית is insufficient].

For example, to create a רשות היחיד one needs  to be enclosed by 3  walls. Now if there are gaps in the walls, one needs to measure the  total of both, all the open gaps and the closed walls to be certain that the majority is closed or walled. 

What if it is exactly 50/50? Is it considered a רשות היחיד? 

We find that there are two opinions in this case and other similar cases. Such as by שחיטה where one needs to shecht the ‘majority’ of the air and food pipe. What would be if one shechts just 50% and the other 50% remains uncut? 

Rav פפא is of the opinion that 50/50 is as good as רוב. 

Why?
His reasoning is, in the case of the walls concerning a רשות היחיד, that the Torah, by stating that we need a רוב (in regards to a רשות היחיד) meant to say that there should not be a רוב of gaps! So by having 50% of walls and 50% of gaps there is no majority of gaps or holes. 

On the other side we have רב הונא with the opinion that 50/50 is not considered as רוב. 

Why?  His reasoning, in the case of the walls concerning a רשות היחיד, is that the Torah by stating that we need a רוב meant to say that there should be a רוב of walls! So by having 50% of walls and 50% of gaps the majority is not walled.  

This topic is known as  פרוץ כעומד – when we have gaps פרוץ, that equal the walls עומד. 

Our Mishna, which validates a 50/50 sukkah, seems to accept the opinion of רב פפא.

Topic #2. 

According to רב פפא, that a 50-50 scenario is as good as a רוב, thereby allowing one to cover a Sukkah with 50% of Kosher סכך and 50% of פסול סכך one must make sure that it is indeed 50% of Kosher סכך and not less!

So here is the second vast topic known as אפשר או אי אפשר לצמצם. This manifests itself in the realm of time and place. 

Time– Can two things occur at the same time?  

Place– Can anything be split exactly 50-50? 

The issue is more complex since on the surface it is seems , in both of the above, that yes,  it indeed can! And why not? 

Let’s see. Time. 

In regards to בכור of an animal that one needs to gift to a Kohen. If a calf that never gave birth happenes to give birth to twin animals at the same time. 

• If they were both indeed born simultaneously and we can ascertain this fact, then both are קדוש and belong to the Kohen.

The question: Can it be possible for both to have been born at the exact same time? 

That is a universal מחלוקת between the רבנן and רבי יוסי. 

The רבנן  say אי אפשר לצמצם. Meaning it cannot happen at the exact same time. 

We discussed what that means. According to the Rambam and Rashi, in nature two things can never happen at the exact same time. 

Why not? Good question. 

[We mentioned the equally puzzling ירושלמי that states that nothing created by Hashem is perfectly square! See here a letter from the Rebbe from 1948 to Rabbi Sholom Rivkin]. 

Tosfos says that of course things can happen at the same time. It’s just that Halachically one cannot ascertain that it did indeed occur at the same time. 

Space

Does the Torah allow to cover one’s Suka with 50% of Kosher סכך and 50% of פסול סכך? 

Can a human really calculate that he placed 50% of Kosher סכך? 

If he placed only 49.999% of the Kosher סכך  it would invalidate his Suka. 

We discussed much more – and will continue  BL”N.