The Gemara in Gittin 22a brings a machlokes in regard to fruits getting nutrients from a tree that is half in ארץ ישראל and half in חוץ לארץ.

ומאי טעמא דרשב"ג דמפסיק צונמא
מאי טעמא דרבי דהדרי ערבי

רשב"ג says since there is a rock between the roots, the nutrients are divided accordingly.
רבי says even though there is a separation, it isn't possible to tell which nutrients go where.

How can they argues on how a tree works, isn't it just facts?

  • What experiment could they run to figure it out? – Heshy Jun 17 '20 at 21:30
  • there's a famous yerushalmi which shows that one did experiments about something. can't recall now/ – Dr. Shmuel Jun 17 '20 at 21:36
  • But here we are trying to work out why there are arguing so he have to make sense of what they are arguing about. – Russell Jun 17 '20 at 22:09
  • @Dr are you thinking of the experiment to see if rice becomes chametz – Double AA Jun 21 '20 at 10:42
  • Ah yes @Double. – Dr. Shmuel Jun 21 '20 at 19:55

Rashi explains the Gemara as being a questions if the roots alone give the Halacha of (not) being in Eretz Yisroel. Everyone seems to agree there is some mixture in the above ground level in the the xylem and phloem. Question is if the the roots alone determine the Halachic status of the tree

The botanical question in itself seems to be a relatively easy question to determine . Replant a bunch of trees while covering the roots on one side and see how it affects the tree.

There actually have been studies done on this question and the results were that although it varies depending on the species of the tree the nourishment of the roots does seem to correspond to the side of the tree they are on. But not exclusively because once it gets above ground it gets into the xylem and phloem and gets mixed throughout the tree.

This is what the Gemara is asking.Do we say (1)that since the ROOTS which gave nourishment to this side of the tree are (not)in Eretz Yisroel the halacha only follows the roots or(2)since once it reaches the above ground level it will have some mixture throughout the tree we don't go by the roots alone.


While it's good question and should be asked, one should keep in mind that the Torah's overall approach doesn't always match up with what we call "facts". There was no laboratory when it was written and even if it did exist, all over there are clear proofs that the Torah works based on mesorah which means what one learned from their rebbe who learned from his rebbe...back to moshe rabbeinu.

For example, with regards to milk and meaty taste transfers (basar bechalav), the Rema states that a [milk drop in a meaty stew] is neutralized if there is a 1/60 majority of the stew. Rema 98:1.

If you put the stew under a microscope and tested for milk, it may or may not show sign of lactose. But not matter what your findings are, the halacha will still stand.

Same with salting meat to get the blood out. After salting and rinsing the meat, one can very well find traces of what scientifically one would call blood.

Back to your question, the two sides are differing from their understanding as it was taught to them and not how it is observed by a horticulturist.

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    You seem to be confusing legal questions and factual questions. Rama never said there is factually no milk after it's 'neutralized'. He said it's legally insignificant. The Torah's approach always matches up with facts אסתכל באורייתא וברא עלמא. What you wrote might be heresy, frankly. – Double AA Jun 18 '20 at 15:48
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    @DoubleAA, then would you consider what the Michtav MeEliyahu says (about killing lice - today's Daf Yomi - and a couple of other halachos) heresy ח"ו? He also says that the facts as known to us don't necessarily match up with the reasons for the halachos as given in the Gemara and posekim, but that it doesn't matter, because the halachah exists independently of the reason given. – Meir Jun 21 '20 at 15:38
  • @Meir Haven't seen it inside in a while so I'm not going to say specifically, but realize also that's a hotly debated topic and not everyone agrees with him. I'm not even sure what you said supports this answer's claims – Double AA Jun 21 '20 at 15:39
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    @DoubleAA The quotation from Michtav MeEliyahu can be found here, p. כט. True that not everyone agrees with him, but that's a far cry from declaring it a heretical opinion. – Meir Jun 21 '20 at 16:44
  • @Meir I only read that single page 29 just now and I don't think that is heretical and I don't think it's what is said in this answer. That page says water is warmer in the morning and it doesn't matter if the sum actually goes below the earth or not, and that the category of bugs prohibited to kill on Shabbat are those that are noticably sexually reproductive. That's fine. Those are legal categories. The Torahs way isn't that bugs don't sexually reproduce factually; it's that that kind of reproduction isn't included in what the Torah meant to forbid on Shabbat call it whatever you want. – Double AA Jun 21 '20 at 17:53

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