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Ask the Rabbi - 292

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Ask the Rabbi

November 18, 2000 / 20 Cheshvan 5761; Issue #292

Thoughtful Work


Isaac Bergman from Brooklyn wrote:

Dear Rabbi,

Recently I read (probably in Scientific American, I don't recall) of a newly-developed brain-scanning device which enables a person to control an onscreen cursor with just his thought alone. If research progresses to the point that a person with his thoughts alone can, say, turn on and off lights, would such "thought actions" be allowed on Shabbat? Technically, all he is doing is thinking! Don't forget that every time a thought goes through your mind, electric currents are generated too, and the same goes for every time you move a muscle.

Dear Isaac Bergman,

In general, the Torah forbids all constructive, pre-meditated acts on Shabbat.

Interestingly, the Torah refers to such acts as "thought-actions" (melechet machshevet; Exodus 35:34), the term which you used.

So, for example, it is forbidden to turn on a light since it causes the filament to glow red (or white) hot; and it is even considered "building" a circuit according to some authorities. Similarly, walking into a dark room and completing the circuit not by manual switch but rather by passing an infra-red beam is regarded as the person's action and is forbidden by the Torah.

In both cases, the person did an action which turned on a light, even though in the second case all he is doing is walking. So too, if a light were to be turned on using just the brain, even though no physical act was performed, since the result is in the physical realm, Jewish Law would forbid it on Shabbat.

Regarding currents in our brain and nervous system during normal activity: The Torah does not forbid using your brain, or any other body part, on Shabbat, even though it generates electric currents. Similarly, the Torah allows eating on Shabbat, even though eating causes the break-down and separation of food into usable and unusable components, activity forbidden if done in a laboratory.

It's actually a commandment to eat and enjoy Shabbat, as Moses said to the Jews, "Eat (the manna) today, because today is Shabbat." (Exodus 16:25) In short, natural bodily functions are allowed on Shabbat.

According to Kabbala, doing mitzvot actually creates spiritual worlds -- still, it is permitted to create these worlds on Shabbat!

Yiddle Riddle


LAST WEEK WE ASKED: I was eating a snack when I had a sudden urge for some bread. I asked my Rabbi, "Should I wash my hands in the special ritual way which is usually required before eating bread?" "No," said my Rabbi. "Should I say the 'hamotzi' blessing usually said before eating bread?" "No," he said. After eating, I asked, "Should I say the 'birkat hamazon' -- the 'Grace after Meals' -- which is normally required after eating bread?" "No," said my Rabbi.

Can you explain what's going on in the above story? Why do the "usual" halachot (Jewish Laws) seem not to apply?

ANSWER: The "snack" I ate at the beginning of the story was a jalapeno pepper. It burned my mouth so much that I had to eat a little bread (less than an olive-size) to cool the burning sensation. I had no desire to eat bread at all except to cool my burning mouth. In such a case, washing is not needed, and hamotzie and birkat hamazon are not said. (Rather, the shehakol blessing is said on the bread, unless at the time of blessing over the tangy food there was intention to eat the bread as a "chaser.")

  • Shulchan Aruch Orach Chaim 212:1
  • Mishneh Berura 158:10, 212:5
  • Aruch Hashulchan 212:5

Thanks to Michael Treblow


The Public Domain
Comments, quibbles, and reactions concerning previous "Ask-the-Rabbi" features.


Re: FIRST JEW IN NORTH AMERICA (Ask the Rabbi Issue #289):

Re: Who were the first Jews in N. America? It is widely understood that the Sephardic refugees from Belem, Brazil, who were rescued by a French ship when they were shipwrecked en route back to Holland after their expulsion from Brazil by the Portuguese in 1654, were the first. However, in the American Jewish Historical Society's publication (June '98, Vol. 86, p. 195) is the story of Jaochim or Chajjim Gans of Prague who arrived in America in summer 1585 aboard one of Sir Walter Raleigh's ships.

David Welsh, Calabasas, California


Your thoughts and insights are wonderful....keep them coming.


Written by various Rabbis at Ohr Somayach Institutions / Tanenbaum College, Jerusalem, Israel.
General Editor: Rabbi Moshe Newman
Production Design: Michael Treblow
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