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Halachot of Electricity on Shabbat

Halachot of Electricity on Shabbat
Halachot of Electricity on Shabbat
Tuesday January 31, 2017
The class will begin in:
6 days, 9 hours, 36 minutes
Instructor: Rabbi Dr. Stuart Fischman
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Halachot of Electricity on Shabbat

Tuesday 1:00PM
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Course Description

Modernity brought a number of questions up in Jewish law, in particular surrounding the use of electricity on Shabbat.

How does Jewish law view use of electricity on shabbat? In this course we will look at some of the earlier sources, such as the Chazon Ish zt”l and Rav Shlomo Zalman Auerbach zt”l, as well as some more current poskim including Rav Asher Weiss and Rav Nachum Rabinowitz of Ma’aleh Adumim.

About Rabbi Dr. Stuart Fischman
Rabbi Stuart Fischman graduated from Yeshiva University in 1980 and the dental school of Columbia University in 1985. Since 1989 he has been studying and teaching at Yeshivat Hamivtar in Efrat. He has rabbinic ordination from Rav Zalman Nechemia Goldberg.

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November 8, 2016 1:00PM - 2:00PM
Halachot of Electricity on Shabbat

Hello Everyone,

   Here is a summary of yesterday's shiur on the use of electricity on Shabbat.

   When I was not much younger than I am today, it was rather simple to circumvent the operation of electrical appliances on Shabbat. Those devices which have become essential in our society such lights, heaters and air-conditioners and hot-water heaters (the ubiquitous kumkums fund in every Israeli home) can all be turned on before Shabbat (either permanently or via a timer) and left alone. However, the times they are a'changing.[1] Mechanical water meters are being replaced by electronic meters which send out a signal to the water company as the reading on the meter changes. Our homes are protected by motion-detectors which are activated as we walk across the spaces that they scan. Many water faucets are activated not by turning a tap but by moving our hands across an electronic sensor. These and other electrical devices demand with urgency that we address the question of using electricity on Shabbat.

   This change is in my opinion one of the great challenges faced by the Halacha in the 21st century.[2] Shabbat is one of the most significant of mitzvot. Hashem says it is our way of testifying to the entire world that we believe that  God is the Creator. To Chazal, violating Shabbat is equal to  idolatry. We need to understand what it means to observe Shabbat and therefore we need to know how and under what conditions we can allow electrical devices to be used  (if at all) in our homes on Shabbat.

    Why is this such a great challenge? Because electricity does clearly resemble anything analyzed in  תורה שבעל פה. Until the late 19th  century  work was done either by humans or their domesticated animals. With the introduction of electrical appliances this changed. Work was now being done by electric motors and light was provided by electric lights. Is pushing on a button or pulling on a switch "work?" This is the question which needed to be answered. The Poskim examined the entire corpus of Halachic literature to find analogies to guide them in answering this question. Not surprisingly different Poskim gave different answers. A great Posek (the Aruch Hashulchan zt"l) ruled that it is permitted to turn on electric lights on Yom Tov (but not on Shabbat).  A leading rabbi in Morocco is cited as having permitted the use of record players[3] and radios on Yom Tov.

   Despite these lenient opinions, a consensus arose to forbid the turning on of electrical appliances on Shabbat and Yom Tov. During the course of these shiurim I hope to discuss the various opinions  in this matter.

   Yesterday we discussed the view of one of the great Poskim of the 20th century, the Chazon Ish zt"l , whose opinion on electricity still figures prominently in Halachic discussions.[4] The Chazon Ish wrote that the activation of an electrical circuit is forbidden on Shabbat as a form of "building" which is one of the 39 categories of מלאכה –work.[5]

   What is the reasoning of the Chazon Ish?

   The Gemarah in masechet Shabbat discusses the permissibility of assembling items which are taken apart after being used, only to be put together again when needed. The Gemarah specifically discusses cots, painters' rollers and lamps as things which are put together and taken apart as needed. The conclusion of the Gemarah is that if the item is put together with nails or pegs it is forbidden to assemble it on Shabbat but if it its pieces fit together loosely it can be assembled on Shabbat.

   From this Gemarah it would seem that "building" should not be a concern when discussing electrical devices. They are turned on and off many times in the course of the day, and nobody nails their light switch in the "on" position. Nonetheless the Chazon Ish says that to activate an electrical device is an act of building.

    Why is this so?

   The Chazon Ish wrote that "building" is the prohibition of creating something which is useful. The item which the Gemarah  uses as an example of permitted building is the painter's roller. If the painter wishes to paint a ceiling he adds sticks to the end of the roller to make it longer. But when he needs to paint a lower section of wall he needs to take the sticks off from the roller. The sticks do not change the roller, by adding them to the roller the painter is not making something "new." Therefore adding the sticks is not an act of building.  However, when a carpenter builds a box from wooden boards he is certainly making something new. When his work is completed nobody sees wooden boards any longer, what they see is a box. Therefore this is an act of building even if the carpenter  planned to take the box apart as soon as he finished building it, what he did was an act of building.

    The Chazon Ish held that the introduction of electrical current to a device (such as a light bulb) is an act of building. Despite the fact that light bulbs are turned on and off with ease and are meant to be turned on and off regularly, turning them on is an act of building. For the light bulb to be useful it needs electricity no less than wooden slats need nails to be made useful. The Chazon Ish acknowledges that the light bulb may only be left on for a short period of time, but this does not change the fact that it was made useful only by the introduction of electrical current to its filament which made it glow.

   The main commentators to Shulchan Aruch, the Magen Avraham and Taz both permitted the attachment of lids to containers and did not view this as building, even if the lids are screwed on tightly. The Chazon Ish said that this does not have any bearing on the question of electricity. The container functions as a container and does not need the lid. The removal and attachment of the lid are simply aspects of its use. . But an electrical device without electricity is not useful at all. It follows, according to the Chazon Ish, that electrical current is what changes a glass bulb into a useful light source and therefore it falls into the category of building because two disparate entities are joined to create something useful..

   The Chazon Ish was a great Posek and his opinion demands repsect. Many Poskim accept his position ( such as Rav Asher Weiss שליט"א). Many Poskim rejected his analysis, most famously הגרש"ז אויערבאך זצ"ל whose correspondence with the חזון איש I hope to study with you.

   Thanks to everyone who participated in the shiur. Stuart Fischman

[1] And I would like to wish the former Mr. Zimmerman a hearty mazal –tov  for winning the Nobel Prize.

[2] The other is the role of women in Judaism.

[3] If you are younger than me you may never have seen one of these. Here is a link to some pictures:



[4] Early Poskim equated electricity to fire, presumably because when electric switches are closed we occasionally see sparks formed. Later Poskim dismissed this comparison ( and the concern for creating sparks)  .

[5] There are two separate categories of מלאכה which address "building." The מלאכה of בונה  forbids building structures while building "items" ( whether boxes or boats or bicycles" ) falls into the category of another מלאכה called מכה בפטיש  or תיקון מנא.


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November 15, 2016 1:00PM - 2:00PM
Halachot of Electricity on Shabbat

Hello Everyone,

    In yesterday's shiur we examined a second approach to the question of how the Halachah categorizes electricity. Last week we saw that the Chazon Ish said that the activation of an electrical appliance is an act of construction and therefore prohibited on Shabbat as a violation of the prohibition against בנין/מכה בפטיש. Yesterday we saw that the Aruch HaShulchan zt"l  and Rav Kook zt"l saw electricity as a form of fire.

   Many Poskim from the late 19th-early 20th  century period considered electricity to be a form of fire. This was either due to the fact that electrical circuits create sparks when closed or that when electricity passes through an incandescent bulb it creates light. This attitude was abandoned by the later Poskim, but I think that Rav Kook's perspective on this subject gives  a valuable lesson on how we can learn Torah and arrive at a Halachic conclusion.

   The Torah forbids lighting a fire on Shabbat:

שמות פרק לה

(ג) לֹא תְבַעֲרוּ אֵשׁ בְּכֹל מֹשְׁבֹתֵיכֶם בְּיוֹם הַשַּׁבָּת:

The question that we need to answer is, "What is fire?"

   This may seem to us a silly question. We all know what fire is. But Rav Kook says that we need to know what the Torah means by the word fire, and this is not so easy to determine.

    When Moshe Rabbeinu had his first prophecy he saw a burning bush:

שמות פרק ג

(א) וּמֹשֶׁה הָיָה רֹעֶה אֶת צֹאן יִתְרוֹ חֹתְנוֹ כֹּהֵן מִדְיָן וַיִּנְהַג אֶת הַצֹּאן אַחַר הַמִּדְבָּר וַיָּבֹא אֶל הַר       הָאֱ-לֹהִים חֹרֵבָה:

(ב) וַיֵּרָא מַלְאַךְ ה' אֵלָיו בְּלַבַּת אֵשׁ מִתּוֹךְ הַסְּנֶה וַיַּרְא וְהִנֵּה הַסְּנֶה בֹּעֵר בָּאֵשׁ וְהַסְּנֶה אֵינֶנּוּ אֻכָּל:

(ג) וַיֹּאמֶר מֹשֶׁה אָסֻרָה נָּא וְאֶרְאֶה אֶת הַמַּרְאֶה הַגָּדֹל הַזֶּה מַדּוּעַ לֹא יִבְעַר הַסְּנֶה:

What was it that Moshe Rabbeinu saw? The Torah says that it was a fire  (אש)   which possessed a remarkable nature. It gave light but it did not consume the material in which it burned. We might say that since it lacked this normal characteristic of fire then this apparition was not really a fire. But Rav Kook wrote that we cannot say this. We need to accept that what the Torah refers to as fire is fire, at least according to the Torah. According to Rav Kook, if we wish to determine the Torah's view of something, we need to know and to follow the Torah's definitions. The Torah says that what Moshe Rabbeinu saw was fire, albeit an unusual sort of fire, but it was nonetheless a fire. It follows that anything that yields light even if it does not consume its substrate is fire. Since electricity does create light as it passes through a light bulb, we must judge electricity to be a manifestation of fire.

    The Aruch HaShulchan gave a second insight into the use of electricity. Even if we were to say to that the lighting of an electric bulb is to be viewed as igniting a new fire[1] the act of lighting the bulb is act of "grama" which is not categorized as "work" on Shabbat or on Yom Tov.

   The distinction between  "grama" and "work" can be subtle and it is still the focus of much debate among Poskim.

   The Gemarah in masechet Shabbat discusses what to do if a table catches fire. It is forbidden to put out a fire on Shabbat. The Gemarah says that in such a case one may fill clay pots with water and place them on the table. When the flames reach the pots, the pots will shatter, the water will spill out and extinguish the fire. The reason that this method of putting out a fire is permitted is based on the following דרשה:

תלמוד בבלי מסכת שבת דף קכ עמוד ב

כתיב לא תעשה [כל] מלאכה - עשייה הוא דאסור, גרמא שרי!

The Aramaic word גרמא is based on the Hebrew root "גרם" which means "to cause." There is apparently a fundamental distinction which we need to make between direct action upon an object as opposed to causing a result to occur. In the case of the fire it would be forbidden to pour water directly upon the flames. This would be, as the Gemarah says, "עשייה" which is "מלאכה"- "work." On the other hand it is permitted to cause the fire to go out. This, the Gemarah says is not עשייה.

    If we are going to apply the principle of גרמא to Shabbat we need to decide upon the degree of "indirectness" necessary to assure that the result which we desire to achieve is due to גרמא.

    In the case of light switches, the Aruch Hashulchan was told[2] that when a light is switched from "off" to "on" one is merely allowing the current to flow. This, he writes, is a גרמא, and permitted on Yom Tov.[3]

   The last of the Great rabbis of Vilna was Rav Chaim Ozer zt"l. He wrote about the use of electric lights in response to the essay of the Aruch HaShulchan.

   In his responsum, Rav Chaim Ozer zt"l did not make reference to the idea that to light an electric lamp on Yom Tov should be permitted as a form of lighting from an existing flame. What Rav Chaim did address was the issue of גרמא. Rav Chaim Ozer made reference to a passage in masechet Sanhedrin. In that suggyah the Gemarah discusses "indirect" forms of murder for which the criminal is not subject to the death penalty.

    In the first case a person shot and arrow at his victim. When he shot the arrow, his victim was holding on to a shield, but the killer snatched the shield away, thus allowing the arrow to strike and to kill the victim. The Gemarah says that in this case the killer does not receive the death penalty because when he fired his weapon, the victim was protected.  The act of snatching away the shield was merely an act of גרמא (as Rashi explains there).

   In the second case a murderer tied up his victim and left him in a ditch. Then the murderer opened up an irrigation canal allowing the water to flow into the ditch and drown his victim.  The Gemarah makes a distinction between two possibilities in this case. If the water flowed immediately upon the victim, then this is homicide and the murderer is put to death. This is called ".כח ראשון" If however the water needed to flow for a certain length of time[4] before reaching the victim, the act of drowning the victim is considered indirect ("כח שני")   and a גרמא so the murderer will not be put to death.

   There is a commentary to masechet Sanhedrin known as the יד רמ"ה. The יד רמ"ה asks, "What is the difference between snatching away the shield and opening the gate to the irrigation canal?"   If in the former case the removal of a barrier is a גרמא then why isn't opening the gate to the canal considered to be גרמא? Why is it that in the case of the irrigation canal the כח ראשון is not גרמא?

  The יד רמ"ה explains that גרמא implies a lack of immediacy. When the shield was snatched away the arrow had not yet reached the victim. On the other hand, the water which drowned the victim was in contact with the gate of the canal. In that case when the water immediately killed the victim, there was no גרמא because of the immediacy of the action. Therefore the murderer is guilty.

    On the basis of this explanation of the יד רמ"ה Rav Chaim Ozer rejects the opinion of the Aruch HaShulchan. The Aruch HaShulchan apparently felt that any action which indirectly leads to an outcome is  גרמא. Striking a match leads directly to creating a flame. Closing an electrical circuit involves the rearranging of the components of the switch which in turn permit the current to flow through the circuit.[5] Therefore, electric switches are merely גרמא according to the Aruch HaShulchan. Rav Chaim Ozer pointed out that גרמא necessarily involves a time-lag between the person's activity and the desired outcome. This is the distinction that the Gemarah makes between כח ראשון  and כח שני. Since electrical circuits (in our case lights) are turned on immediately, they cannot be viewed as examples of גרמא.[6]

   Thanks to everyone who attended the shiur. Bye, Stuart Fischman



[1] The Aruch HaShulchan himself seemed to view the electric current as a form of fire. Therefore switching a light on which allows a current to pass into the light bulb is merely lighting a flame (the filament) from an existing flame ( the electric current) and permitted on Yom Tov.

[2]  In his short essay he admits that he had never seen an electric light and was writing on the basis of what he was told about electricity and circuitry.

[3] גרמא  also permitted on Shabbat, but the Aruch HaShulchan did not permit light electric lights on Shabbat, presumably because his היתר was also built on the concept that electricity itself is a form of fire. Therefore to light an electric light is merely lighting from an existing flame which permitted only on Yom Tov.

[4]  And this length of time also needs definition.

[5]  It is not clear to me how light switches were described to the Aruch Hashulchan.

[6] To be fair to the Aruch Hashulchan, he may not have been aware that electric lights turn on immediately, since he writes that he had never seen an electric light.


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November 22, 2016 1:00PM - 2:00PM
Halachot of Electricity on Shabbat

Dear Everyone,


  In yesterday's class we finished the teshuva of Rav Chaim Ozer zt"l on the use of electric lights (the incandescent type) on Shabbat and Yom Tov.

   Rav Chaim Ozer wrote this teshuvah as a rebuttal to the opinion of the Aruch Hashulchan who permitted the turning on of electric lights on Yom Tov. The Aruch Hashulchan  permitted this because:

a) the electrical current is analogous to fire, and it is permitted on Yom Tov to light a flame from a pre-existing flame[1],


b) the closing of an electrical circuit via a switch does not directly close the gap within the circuit. Rather the closing of the circuit is done by means of a mechanism which removes an obstacle/insulator and only afterwards is the circuit closed allowing the electrical current to flow to the light bulb. This indirect activation is known in the Halacha as גרמא  , and גרמא is permitted on Shabbat.

   Ra Chaim Ozer zt"l did not address the first point of the Aruch Hashulchan at all. He focused his teshuva on the subject of גרמא. The concept of גרמא  figures prominently not only in the laws of Shabbat, but in the laws of damages as well. An example of גרמא by damages is the following. If a person spills water in the street, and someone slips on the water and so (a) dirties his clothes in the puddle and (b) sprains his wrist when he hits the ground, what is the extent of the liability of the person who spilled the water? In Bava Kama the Amorah רב says that in such a case the person who spilled the water is liable to pay for cleaning the person's clothes, but he is not responsible for the sprained wrist. The reason is that the damage done to the clothing was done directly by the hazard that he created (the puddle). However when the person slipped and hit the ground, the puddle only caused the fall, the actual damage was done by the ground. The person who spilled the water does not own the ground. Therefore, he only caused an event wherein the damage was done by a different party (the ground). This is גרמא and people are not liable in גרמא  cases.[2]

   גרמא can be explained as an indirect method of accomplishing a task. While technology is a modern phenomenon the question of גרמא on a theoretical level was debated hundreds of years ago by the Magen Avraham and Even HaOzer (both of these works are commentaries to Orach Chaim).

   The Magen Avaraham wrote that if a person places wheat into the receptacle of a water operated mill, he is not liable for חילול שבת when the mill grinds the wheat into flour. The Magen Avraham holds that the Torah prohibition against grinding only applies to grinding by hand. The grinding done by the water mill is only גרמא.[3]

   The Even Haozer takes very strong exception to the idea of the Magen Avraham. He makes several points in attacking the Magen Avraham's broad interpretation of גרמא. גרמא  has two implications:

a) for purposes of liability, an action done viaגרמא  is not attributed to the person who set the process into motion

b) for purposes of הלכות שבת, an act done via גרמא  is not considered to be "work."

The Even Haozer gives an example of an act which is not viewed as גרמא for the laws of damages but is considered to be גרמא for the laws of Shabbat. The case is when a person takes out his cow to graze. If he takes his cow out to graze in another person's pasture, the owner of the cow is liable for damages done to the pasture by his cow. The actions of the cow are attributed to the person. On the other hand, when a person takes out his cow to graze on Shabbat, this is permitted even though the cow is ripping the grass off from the earth which is forbidden to do on Shabbat. In this case the actions of the cow are not attributed to the person. How do we differentiate between the two cases?

   The Even Haozer explains the distinction as follows. For the laws of damages, we apply the rule of גרמא  when the outcome is not certain. Therefore, if a person starts a fire but then a wind comes and fans the fire causing it to spread into a neighbor's property the person who started the fire is not liable. But when a person takes a cow to graze in a neighbor's field, the cow will definitely eat. Therefore we attribute the damage done to the owner of the cow and do not say the damage was via גרמא.

   On Shabbat we are concerned with the intention to perform one of the 39 acts categorized as מלאכה/work. When a farmer wishes to winnow his grain by tossing it into the wind, he wishes to perform work via the wind, therefore he is judged to have violated the Shabbat even though the actual work was done by the wind. This is why the wind serves as a factor to exonerate the person who started a fire which was spread by the wind into a neighbor's property, while for purposes of Shabbat work done by the wind is still viewed as "work."  When a person takes his cow to graze on in a field, the owner of the cow is only thinking about having his cow eat, he is not thinking about the מלאכה of קוצר. Since his intention is not on doing a מלאכה he is not considered to have desecrated the Shabbat via his cow's action.

    The Even Haozer therefore disagrees with the Magen Avraham's ruling concerning a water mill. Even though the person does not perform the actual grinding, since he put the grain into the receptacle in order to have it ground, this is considered to be an act of grinding and is prohibited מן התורה.

    Rav Chaim Ozer writes that based on the Even Haozer's interpretation rule of גרמא we cannot accept the lenient ruling of the Aruch Hashulchan. Even if it were true that the electrical switch operates via a גרמא  mechanism, the intention of the person turning on the light is to cause the filament to glow, and the turning on of the switch is the common method obtaining light. Therefore closing a circuit cannot be viewed as a גרמא.

   Rav Chaim Ozer concedes that that the Magen Avraham has a powerful basis for his view of גרמא  in the commentary of the רא"ש to בבא קמא. The Even  Haozer says that any מלאכה done deliberately on Shabbat via an indirect method is forbidden (based on the example of winnowing which is forbidden on Shabbat). The רא"ש says that winnowing is the exception to the rule. According to the רא"ש no indirect action is ever considered to be מלאכה. Winnowing is the sole exception  because the only way that one can winnow is with the aid of the wind. It follows that since grinding can be done by hand, grinding done by means of a water driven mill is indeed גרמא according to the רא"ש.

   In his final ruling Rav Chaim Ozer says it is forbidden to turn on an electrical light on Yom Tov.

   Thanks to everyone who attended the shiur. Stuart Fischman

[1]   I want to point out here that the Aruch Hashulchan wrote in his teshuvah that had never seen an electric light himself, and that he wrote his opinion on the basis of what he was told about electrical circuits.

[2]  See Rashi to Baba Kama 28b    ד"ה הזיקתו.

[3] The Magen Avraham does not use the word גרמא to describe the water mill, but it is commonly understood that this is his intention.


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November 29, 2016 1:00PM - 2:00PM
Halachot of Electricity on Shabbat

Hello Everyone,

   In our series of shiurim dealing with the use of electricity on Shabbat we have until now dealt with the opinions which hold that electricity is essentially forbidden מדאורייתא. The reasons for this prohibition are that either electricity falls within the category of fire, or that by closing a circuit a person is constructing the appliance.

   Yesterday we were introduced to the opinion of הגרש"ז אויערבאך זצ"ל who was one of the first[1] prominent Poskim to say that for purposes of Shabbat, electricity is innocuous. According to הגרשז"א זצ"ל the only question that needs to be asked (regarding the operation of an electrical appliance on Shabbat) is what is being done by the appliance. Closing or opening an electrical circuit is not in itself a form of "work" forbidden on Shabbat.

    Rav Auerbach zt"l was drawn to examine the issue of using electrical appliances on Shabbat because of the need of his mother to use a hearing-aid.  After careful study of the subject Rav Auerbach zt"l concluded that it was permitted to turn the hearing-aid on and off on Shabbat. When the Chazon Ish zt"l published his work on Hilchot Shabbat Rav Auerbach was astounded to read that the Chazon Ish felt that the operation of electrical devices is a form of בנין . As far as the Chazon Ish was concerned, Rav Auerbach had permitted his mother to desecrate the Shabbat.

    The Chazon Ish was one of the great Halachic authorities of his era and his opinion was not to be dismissed lightly. Rav Auerbach entered into a correspondence with the Chazon Ish in which each side explained their position on the matter. It was this correspondence which we studied yesterday.[2]

    Rav Auerbach expressed his opinion that the מלאכה of בנין is only relevant when the object is being built permanently. Objects which are meant to be assembled and dismantled as a matter of course do not come under the rules of בנין. Furthermore, Rav Auerbach cited the שלחן ערוך הרב who wrote that בנין must involve strength and skill. Turning an electrical switch on or off is simply not an act of בנין.

    Rav Auerbach acknowledged that there are Poskim who forbade re-setting and winding a clock which stopped on Shabbat and ruled that this is an act of בנין. But Rav Auerbach pointed out that there is a basis for distinguishing a stopped clock from an electrical appliance. A clock is meant to constantly display the correct time. One can make the claim that when a clock has stopped it is essentially broken.[3] But no one can say that when an electric fan is turned off it is "broken," nor can one say that by turning it on it has been "built."

    Rav Auerbach next addressed the Chazon Ish's idea that when something intangible ("צורה" in Hebrew) is combined with something tangible  ( "חומר") this is a significant act of construction. If this is so, then why does the Chazon Ish permit the use of Primus stoves on ימים טובים? Primus stoves work by being heated and the heat draws up the kerosene fuel from its reservoir at the base of the stove. Heat is intangible. Why, asked Rav Auerbach, is it permitted to add heat to a metal appliance but not electrical current?

    The Chazon Ish replied to Rav Auerbach. He opened his letter by acknowledging that to rule on the matter of electricity is essentially a matter of judgement. As he sees it, there is a basic difference between heat and electricity.  Heating metal ( such as the tube of a Primus stove) is introducing something extraneous ( the heat) to the metal, but the nature of metal is to expel the heat.[4] Introducing an electrical current to a wire is entirely different according to the Chazon Ish. The metal wire has a latent, inherent electrical potential which is made manifest by being attached to a source of current. This  attachment is an act of construction and is actually an act of giving life to the wire ("ממות לחיים") .

   The Chazon Ish rejected Rav Auerbach's claim that since the act of turning the appliance on is not permanent (since eventually the appliance will be switched off) it is not an act of בנין. The Chazon Ish explained that the person's intentions have no bearing on the definition of an act as being a מלאכה. Consider a tailor- if a tailor sews a button onto a shirt with the intention to tear the button off the tailor was nonetheless guilty of חילול שבת because he performed the מלאכה of תפירה. Closing the circuit is an act of בנין regardless of the intention to turn the appliance off at some later time.

   Rav Shlomo Zalman Auerbach received the reply of the Chazon Ish and read it, as he wrote, with a mixture of joy and sorrow. It was a source of joy to receive a letter from the Chazon Ish, but he was filled with sorrow to read that the Chazon Ish still felt that to turn the hearing aid on or off is חילול שבת.

    Rav Shlomo Zalman Auerbach wrote in his reply to the Chazon Ish, that he does not understand at all what the Chazon Ish said about the difference between heat and electricity. If electricity is "inherent" in the metal wire then so is heat.[5] Furthermore, how could the Chazon Ish say that the electric current leads to an expression of something inherent in the wire? Rav Shlomo Zalman Auerbach wrote that he could accept this idea if the wire (or filament in the light bulb) would continue to glow and give heat after being disconnected from the power source. But as soon as the circuit is opened the wire ceases to glow. The electric appliance only functions as long as it is connected to the power source. This being the case the appliance cannot be said to be "built" since it is continuously dependent on a supply of current. Rav Shlomo Zalman Auerbach returned to the example of the Primus stove. Why is permitted to operate a Primus stove which draws kerosene from a tank, but it is forbidden to operate a hearing-aid which draws electrical current from  a battery?

    The Chazon Ish replied to Rav Shomo Zalman Auerbach. He repeated his opinion the addition of an electric current to an electric appliance is as much an act of construction as nailing together boards to build a box. It is the closing of the circuit which allows the current to flow which is the significant act. [6] The fact remains that when the appliance is turned off it is inert. When the circuit is closed and electricity is flowing through the wires it is serving its purpose which is the aim of the person who closed the circuit. This is תיקון מנא. The Chazon Ish acknowledged that "use/שימוש" is not a constructive act. Therefore the addition of heat to metal per se is not בנין. However, when something was made via intelligence and talent this is a מלאכה.[7]

    The exchange of letters did not lead to either party changing their mind about electricity.  In the absence of a סנהדרין which could put these competing views to a vote there really is no "last word" regarding the use of electricity on Shabbat. There are Poskim who adopt the view of the Chazon Ish zt"l  and there are those who adopt the view of Rav Shlomo Zalman Auerbach zt"l.

Thanks to everyone who participated in the shiur. Stuart Fischman

[1] He may have been the very first, but I cannot say that with any degree of certainty.

[2] I did my best yesterday and today to explain the position of the Chazon Ish. The Chazon Ish both in his published work as well as in his correspondence used difficult language to convey his view on electricity. Rav Shlomo Zalman Auerbach himself had difficulty with the language of the Chazon Ish, so it is no surprise at all that I struggled with it. The original texts are posted on the web-page of the shiur and I invite everyone to look at them.

[3] This is the view of the 19th century authority , the חיי אדם. There were authorirites who disagreed with this view.

[4] A student of thermodynamics would describe this phenomenon differently.

[5]  Since heat is merely the product of the motion of the molecules in the wire.

[6]  The Chazon Ish at this point apparently withdrew his argument based on the nature of the electric current:

"...ולזה א"צ להכנס בצורת החשמל בחוט..."

[7] I think that with this last line, the Chazon Ish was clarifying the difference between operating the Primus stove and an electric appliance. The Primus stove operates via heat (https://en.wikipedia.org/wiki/Primus_stove) , and metals by their nature absorb and radiate heat. Therefore applying heat to the Primus stove is not an act which can be categorized as מלאכה.

On the other hand, electric circuits are designed and reflect the application of intelligence and talent. There is an element of novelty to an electric device which is not present in the comparatively primitive Primus stove. Therefore the operation of an electric device is a מלאכה


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December 6, 2016 1:00PM - 2:00PM
Halachot of Electricity on Shabbat

Hello Everyone,

    In Tuesday's shiur we studied the opinion of Rav Shlomo Zalman Auerbach zt"l regarding the use of electricity on Shabbat and Yom Tov. We have already studied his correspondence with the Chazon Ish zt"l in which he rejected the position of the Chazon Ish. The Chazon Ish claimed that the activation of an electrical device is forbidden מדאורייתא because it is an act of construction which is מלאכת בונה.

     Rav Auerbach zt"l rejected this idea. According to Rav Auerbach, construction is an inherently one-time activity. But electrical appliances are constantly turned on and off. Therefore even though they cannot be operated until electricity is "added" to them, this addition of electricity needs to be viewed as the means of "usage" of the device and not as the construction of the device.

  Since this is so, why should it be forbidden to operate electrical devices on Shabbat?

  Rav Auerbach zt"l makes it clear that if electricity is used to perform one of the 39      מלאכות then it would be forbidden to use that device on Shabbat. For example, since it is forbidden to heat metal until it glows , it is forbidden to turn on an incandescent light on Shabbat. But if no מלאכה is involved, what is the basis for prohibiting the use of electrical devices on Shabbat?

   In the תשובה which we studied[1] Rav Auerbach addressed the use of telephones, loudspeakers and hearing aids. He was hard pressed to find a basis for the prohibition and finally based the prohibition on two earlier authorities. In a previous class we discussed the debate in the 18th century regarding winding stopped clocks on Shabbat. Some authorities permitted it and some forbade it, saying that it is אסור מדאורייתא. Rav Yakov Emden zt"l was one of the great authorities of the 18th century. He personally felt that it is permitted to wind a clock on Shabbat, but he avoided doing so.  The reason for this was that he was concerned that people might mistakenly perform actual repairs on broken objects based on the fact that it is permitted to wind a clock. Rav Auerbach zt"l wrote, that what was true in the time of Rav Yakov Emden is certainly true today and so we must avoid using any electrical devices in order to prevent error by the public. When the telephone  was invented in the 19th century Rav Yitzchak Shmelkes zt"l forbade using them on Shabbat. He wrote that introducing current into wires is a form of מוליד, which is the Rabbinic prohibition against making changes in objects.[2] Rav Shmelkes zt"l[3] felt that introducing an electrical into a circuit is "making a change." Rav Auerbach zt"l personally did not agree that מוליד is relevant to electrical current, and as a matter of principle we should not broaden the category of מוליד beyond what the Gemarah decreed to be prohibited                 ("...והבו דלא לוסיף עלה.") . Nevertheless, Rav Auerbach zt"l felt bound by the ruling of the בית יצחק . Rav Auerbach applies to the ruling of the בית יצחק the Talmudic concept of "[4] .שכבר הורה זקן"

   We see that Rav Shlomo Zalman Auerbach zt"l felt that as long as no מלאכות  were done by the appliance, an electrical appliance could be activated on Shabbat. In this spirit, he wrote that in his opinion  it is permitted in case of great need               ("במקום צורך גדול") to use a telephone on Shabbat.

   The opinion of Rav Shlomo Zalman Auerbach zt"l is very, very significant. According to the Chazon Ish zt"l there is very little room for flexibility when electricity is concerned. This is because he held that the activation of the electrical device is an איסור דאורייתא. However, according to Rav Shlomo Zalman Auerbach zt"l ( and as we shall see Rav Henkin zt"l also held like Rav Auerbach zt"l)  the prohibition against closing an electrical circuit may be under many circumstances Rabbinic, questions regarding the activation of electrical circuits may be approached with an eye towards leniency.

    Thanks to everyone who attended the shiur. Stuart Fischman


[1] מנחת שלמה (קמא) סימן ט

[2]  An example of מוליד is burning incense on Yom Tov in a clothes closet in order to give the clothes a pleasant fragrance.

[3] שו"ת בית יצחק , יו"ד, סימן לא

[4] Rav Auerbach zt"l cited the opinion of שו"ת שערי דעה who could find no reason to forbid using a telephone on Shabbat. It would  seem that the בית יצחק   was more authoritative in the opinion of Rav Auerbach zt"l.


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December 13, 2016 1:00PM - 2:00PM
Halachot of Electricity on Shabbat

Hello Everyone,

    Yesterday we moved on to the opinions of the contemporary Poskim regarding the use of electricity on Shabbat.

   We began the shiur with the approach of Rav Nachum Rabinowitz שליט"א. He has written a monumental commentary to the Rambam , serves as the Rosh Yeshivah in Ma'aleh Adumim, and wrote a volume of responsa titled שיח נחום  as well as several essays in the Halacha periodical תחומין.

   In his writings on the subject of electricity, Rabbi Rabinowitz follows in the footsteps of his mentor, Rav Henkin zt"l who (like Rav Shlomo Zalman Auerbach zt"l) held that there is no particular prohibition regarding electricity. Rather, when deciding if it is permitted to operate an electrical device on Shabbat we need to examine whether one of the 39  מלאכות are performed by the appliance. If the appliance does not perform one of the 39 מלאכות then we may either permit its use if there is a need for it ( as Rav Shlomo Zalman Auerbach zt"l did with hearing aids) or forbid it if it seems to resemble work   עובדין דחול"."

   Rav Rabinowitz is very consistent in applying Rav Henkin's approach to electricity. We saw already that Rav Auerbach zt"l permitted the user of a hearing aid to turn the device on and off on Shabbat. Nevertheless, Rav Auerbach said that it is not permitted to replace the batteries when they run down. He compares replacing batteries to replacing torn shoelaces[1]which is forbidden on Shabbat. Rav Rabinowitz, on the other hand, permits a person who uses a cochlear implant to replace its batteries and this is permitted even if by replacing the batteries various LED will go on. Rav Rabinowitz[2] explains that no מלאכות דאורייתא are done, neither by the implant itself nor by the LEDs. Therefore the only reason to forbid changing the batteries would be the more general Rabbinic prohibition of עובדין דחול , but  in a case of great need (such as restoring the ability to hear) this prohibition is not invoked.[3]

   One of the leading authorities regarding the use of electrical devices on Shabbat is Rav Yisrael Rosen, who is the founder of the Zomet Institute which specializes in designing electrical devices which can be used on Shabbat. Their products are used in Israeli hospitals, the IDF and wherever there is a necessity for such devices. Rav Rosen is also the editor of the periodical תחומין. At the end of Rav Rabinowitz's article on the use of cochlear implants, Rav Rosen wrote an addendum. In this addendum Rav Rosen provided some technical instructions regarding the implants. What is of interest to us is what he wrote regarding changing the batteries on Shabbat:

אורך חיי הסוללה בציוד FM, במקלט ובמשדר, אינו מיועד ליום שלם. ניתן להשתמש בשבת עד לכילוי הסוללה. אם חיוני - יש המתירים לבצע החלפת סוללה ב'שינוי'.

Whereas Rav Rabinowitz finds no objection to changing the batteries, Rav Rosen only permits this if it is (a) a vital necessity and (b) only then via a שינוי.[4]

   In a תשובה printed in his שו"ת שיח נחום Rav Rabinowitz discusses the questions surrounding LEDs in greater depth. He addresses two issues:

a) is it permitted to walk into an area protected by an alarm system which respond to motion by flashing LEDs?

b) is it permitted to use a key card to open a door in a hotel when inserting the card causes LEDs to light up?

   Additionally, he discusses whether it is permitted to walk into a doorway which has doors which open automatically.

   To all three questions Rav Rabinowitz replies that these actions are permitted. We have seen already that in these cases Rav Rabinowitz would say that no מלאכה דאורייתא is involved. The only remaining question is whether there is a Rabbinic issue of עובדין דחול. This prohibition is not invoked here. To understand this leniency we need to understand a parameter known as פסיק רישיה. On Shabbat מלאכות are forbidden when they are done for the usual constructive purpose. For example, it is forbidden to kill an animal on Shabbat. But the usual reason for killing an animal is because it is need for food. What about a case where a parent kills a chicken so that his or her child wants to use the chicken as a toy? Would this be permitted? The Gemarah says, no,  this is prohibited because it is inevitable that by cutting off the chicken's head the chicken must die (פסיק רישיה ולא ימות) .

    The Rashba qualifies this rule of פסיק רישיה. One of the 39 מלאכות is צידה- trapping an animal. The Mishnah says that if a deer enters someone's home on Shabbat it is forbidden to close the door to the house because this would trap the deer inside. The Yerushalmi on this Mishnah says that if the person's intention in closing the door is only to protect his belongings, then it is permitted to close the door. The Rashba accepted this Yerushalmi as normative.[5] The Yerushalmi/Rashba apparently understand פסיק רישיה as relevant when the act is clearly a מלאכה but the person is performing the act for other than the "classical" reason. It is true that the final Halacha is not in accordance with the Yerushalmi/Rashba. However, Rav Rabinowitz writes, in these cases which involve LEDs or automatic doors, the person is merely walking, and walking is by no means a מלאכה. Since it is a purely innocent act the label of מלאכה cannot be attached to it. One can go further and say that the label of "incidental מלאכה" cannot be attached to it because, as different from the case of cutting off the head of a chicken, the person is walking and not coming into any contact with any of the electrical circuits.

   For all of these reasons Rav Rabinowitz sees no problem with activating LEDs or automatic doors on Shabbat.

    Other Poskim take strong exception to the lenient view of Rav Rabonowitz. Rav Asher Weiss שליט"א , a prominent Poskek in Yerushalyim wrote a teshuvah in his work מנחת אשר to an unnamed correspondent who permitted the use of automatic doors on Shabbat.  He wrote that he was  shocked and horrified to see this idea in print. Rav Rosen, who is the editor of תחומין also disagreed very strongly with rav Rabinowitz. Rav Rosen holds that Rav Rabinowitz is sanctioning the deliberate operation of electrical devices on Shabbat which is something that Rav Auerbach zt"l never did.

    These are the major opinions on the use of electricity on Shabbat. Thanks to everyone who attended the class. Stuart Fischman


[1] עיין שש"כ (מהודרה השלישית) פרק טו הערה (ריא) מתי יש בהשחלת שרוך איסור תורה או איסור דרבנן.

[2] ב"תחומין" כרך לא, עמוד 30

[3] In his essay Rav Rabinowitz does not address the comparison of replacing dead batteries to replacing torn shoelaces. Rather he compares inserting batteries to the assembly of portable cots, which the Gemarah permits as long as the cots are not assembled in a permanent fashion. Since we all know that batteries eventually die, electrical devices are designed for the easy removal and insertion of batteries. Therefore the exchange of batteries is "normal use" and not an act of "repairing" or "assembly."

[4]  I imagine that Rav Rosen sets these limits out of deference to the opinion of Rav Shlomo Zalman Auerbach zt"l.

[5]  I would emphasize that other Rishonim do not accept this Yerushalmi and the Shulchan Aruch does not accept the Yerushalmi/Rashba in this case.


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December 20, 2016 1:00PM - 2:00PM
Halachot of Electricity on Shabbat

Hello Everyone,

   In today's shiur I tried to present two very distinct views over what it means to observe Shabbat. Over the past few weeks we have focused on the views of those authorities who hold that the use of electricity on Shabbat is not in itself problematic. Working off of this premise some authorities permit various activities which involve electricity such as walking through automatic doors or using "key cards" to open doors on Shabbat.

    I feel an obligation to present both sides of Halachic issues so I opened today's shiur with the rulings of the former Chief Rabbi of Israel and current Chief Rabbi of Jerusalem, Rav Shlomo Amar שליט"א .  Rav Amar is a vociferous opponent of many of the technological innovations introduced by the Tzomet Institute. Rav Amar, in the essay which we studied today, presents two interesting views of developing "Shabbat-friendly" electrical devices.

    The Chazon Ish zt"l ruled that it is forbidden to activate any electrical circuit because it is a constructive act of בונה which is one of the 39 מלאכות. The Chazon Ish zt"l held no official position, but his works and rulings are studied and influential. This is (understandably) particularly true in the city of Bnei Brak where he lived. In Bnei Brak there is a hospital ".מעייני הישועה"  This hospital was built with the guidance of the leading rabbis of Bnei Brak. Rav Amar writes that when it came time to plan the hospital's elevators the rabbis who were directing the building process ruled that "Shabbat elevators" should not be placed in the building. Anyone who has visited an Israeli hotel knows that "Shabbat elevators" are programmed to automatically go to every floor and open and close their doors on their own. This eliminates the need for the passengers to operate any circuits. The rabbis of Bnei Brak explained that if there is a need due to פיקוח נפש to use the elevator then it is permitted of course to use the regular elevator. If there is no פיקוח נפש then the people can walk.

    Rav Amar mentions this story to show that there is a "big picture" which he feels the rabbis of Tzomet are missing. Shabbat needs to be different from the other six days of the week. It is the day that we set aside to mark the fact that we believe that the world was created by Hashem's "work" of the first six days of the Creation. Just as He rested, we rest. As it happens, the Torah defines "work" as thirty-nine tasks which were involved in the building of the משכן. These are Biblically prohibited. The Rabbis of the Talmud added other decrees to protect the sanctity of the Shabbat. For example, it is Biblically permitted to instruct a non-Jew to perform work on Shabbat, but the Rabbis of the Talmud forbade this. Shabbat must be a day of rest.

   Some people must work on Shabbat. Doctors, police, soldiers and other emergency services need to operate every day of the year. The Tzomet Institute manufactures "work around" devices that allow these providers of essential services to carry out necessary tasks without performing any of the מלאכות. Rav Amar himself sees these innovations as something positive. The rabbis of Bnei Brak say that their risk for abuse far outweighs any benefit that they provide. The rabbis of Bnei Brak say that if there is a matter of פקוח נפש then there is no need at all for any "work-arounds." However once the public hears that there is a way to use a smart-phone or computer without violating the Shabbat these "Shabbat-friendly" devices will become widely available and Shabbat will no longer be distinguishable from any other day.

   Rav Amar shares this fear of Shabbat becoming like a week day via the widespread use of "Kosher switches." He mentions that he was approached by an engineer who offered to develop a "grama switch" to operate the Jerusalem Light Rail system. He maintains that the great majority of rabbinic authorities oppose the Tzomet Institute's work and those authorities who did approve of their work never dreamt that the devices would be used outside of hospitals or the military.

    Rav Amar specifically forbade the use of electric carts by the disabled to attend the synagogue on Shabbat. He says the disabled should pray at home, and their use of these carts is חילול שבת .

    Rav Yisrael Rosen is the director of the Tzomet Institute. He naturally objected to Rav Amar's ruling. Rav Rosen wrote that he was personally instructed by Rav Auerbach zt"l to develop the grama-operated cart for a disabled man in Jerusalem, and that Rav Auerbach would send disabled people to him to have carts made. Ray Yehoshua Neuwirth zt"l, the author of שמירת שבת כהלכתה wrote favorably about the grama-operated carts. He congratulated Rav Rosen for his valuable work in this field.

    Rav Rosen of course realizes that his technology, like any other technology, may be abused. Nevertheless, there can be no denying that these carts are a blessing for the disabled.

   These are the competing views on technology and Shabbat.

   I hope that you enjoyed the shiurim and I look forward to meeting with you after Chanukah. Stuart Fischman.


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January 3, 2017 1:00PM - 2:00PM
Halachot of Electricity on Shabbat

Hello Everyone,

    In yesterday's shiur on the use of electricity on Shabbat we reviewed the סוגיאות of the Gemarah that deal with the concepts of גרמא and הסרת המונע .Briefly put the relevant passages are as follows. On page 120b of masechet Shabbat the Gemarah says that it is forbidden to open a door on Shabbat if that door faces a lamp. The act is forbidden because by opening the door one allows the wind to enter the room and this will extinguish the flame in the lamp. Later on the same page the Gemarah says that it is permitted to line up clay pots filled with water in front of a fire. Even though the pots will shatter and spill their water putting out the flame this is permitted. The Gemarah says that this sort of act is not "work" in the context of Shabbat. Rather this method of putting out a fire is "גרמא" an indirect means for performing a task, and is permitted on Shabbat.

   On page 77b of masechet Sanhedrin we are introduced to the subtle concepts of כח ראשון and כח שני . The Gemarah says that if a person ties up somebody else and places him in front of a sluice gate and then opens up the sluice gate thus allowing the water to flow and drown the victim, this person is guilty of murder. The Gemarah then states that culpability is limited to cases where the victim was killed by כח ראשון but if the death was caused by כח שני then technically the perpetrator is not guilty of murder. Rashi explains that כח ראשון is the water which flowed out immediately once the gate was opened. However ,water which flowed out later is attributed to the assailant and therefore the victim's death was due to גרמא.

   The third סוגיא is in masechet Bava Kama, page 60a. The Gemarah there discusses liability for damage done by a person's fire. If a person starts a fire which spreads because of the wind, he is not liable for damages done by the fire. The Gemarah asks why is this case not similar to a parallel case in the laws of Shabbat. One of the 39 forbidden acts forbidden on Shabbat is winnowing grain. Winnowing is done by tossing the mixture of grain and chaff into the air whence the wind blows the chaff away while the grain falls back to the ground.  We see in this case that work done by the wind is attributed to the person who participates in the act. So too, says the Gemarah, the person who started the fire should be held responsible for the act done by the wind.

    Rav Ashi answers this question. He says that by Shabbat what is forbidden is "מלאכת מחשבת" and that was done in the case of winnowing. By the case of the fire, the spread of the fire by the wind was a גרמא and in liability law people are not responsible for גרמא. Rashi explains that מלאכת מחשבת means that a task was achieved as planned. Even though the actual work was done by the wind, since this was the plan, this act of separating the wheat from the chaff is attributed to the person who tossed the mixture into the air.

    The Rosh asks, why is it that in Bava Kama the Gemarah forbids acts of גרמא on Shabbat while in masechet Shabbat the Gemarah permits גרמא? He answers that winnowing (זורה) is different from the other acts forbidden on Shabbat. The other acts forbidden on Shabbat (e.g. writing, sewing, weaving etc.) are done directly by the person. Therefore performing them via גרמא is not included in the Torah's category of "work." On the other hand, winnowing can only be done with the aid of the wind. Since the act of winnowing is included in the list of 39 forbidden acts it must be that it is the exception to the rule that גרמא is permitted.

    In Israel there are research institutes where electrical devices are designed to work via גרמא. These גרמא  circuits allow people and organizations who provide vital services to perform essential activities without violating Shabbat. It is important to keep in mind that even though the Gemarah permits גרמא this permission must not be abused. This how the Shulchan Aruch rules with regard to גרמא:

שולחן ערוך אורח חיים הלכות שבת סימן שלד

סעיף כב

תיבה שאחז בה האור, יכול לפרוס עור של גדי מצדה האחר שלא תשרף; ועושים מחיצה בכל הכלים להפסיק בין הדליקה, אפילו כלי חרס חדשים מלאים מים שודאי יתבקעו כשתגיע להם הדליקה, דגרם כיבוי מותר. הגה: במקום פסידא (מרדכי פרק כ"כ).

The Rema says that גרמא can only be used to prevent loss. In Israel it is clear that hospitals, the police and army must work on Shabbat. Allowing them to use גרמא  circuits eliminates the need to weigh every action to examine if it is truly פיקוח נפש.

   It follows that it would be a travesty of Halacha to use גרמא circuits to operate bread-making machines or home entertainment systems on Shabbat. It may very well be that no מלאכות would be done by operating these devices via גרמא circuits but doing so would be a gross violation of the spirit of Shabbat. ישעיהו הנביא taught us thousands of years ago:

ישעיהו פרק נח

(יג) אִם תָּשִׁיב מִשַּׁבָּת רַגְלֶךָ עֲשׂוֹת חֲפָצֶיךָ בְּיוֹם קָדְשִׁי וְקָרָאתָ לַשַּׁבָּת עֹנֶג לִקְדוֹשׁ ה' מְכֻבָּד וְכִבַּדְתּוֹ מֵעֲשׂוֹת דְּרָכֶיךָ מִמְּצוֹא חֶפְצְךָ וְדַבֵּר דָּבָר:

(יד) אָז תִּתְעַנַּג עַל ה' וְהִרְכַּבְתִּיךָ עַל במותי בָּמֳתֵי אָרֶץ וְהַאֲכַלְתִּיךָ נַחֲלַת יַעֲקֹב אָבִיךָ כִּי פִּי ה' דִּבֵּר:     

    What is left for us to examine is to define גרמא. גרמא is commonly understood to mean an indirect action, but how do we judge what actions are indirect?

    There is a well-known ruling in שמירת שבת כהלכתה that it is permitted to adjust on Shabbat a "Shabbat clock" to delay the turning-off of an appliance. In the footnote to this ruling (chapter 13, note 100), Rav Auerbach zt"l is quoted as saying that this action is only postponing the arrival of a termination, and is not analogous to adding oil to a lamp to enable it to burn longer. This, he adds, is a permitted גרמא.

    Rav Herschel Shechter שליט"א is one of the preeminent students of Rav Soloveitchik zt"l. In his book, בעקבי הצאן  he writes that Rav Soloveitchik zt"l was opposed to many of the leniencies put forward as being within the category of גרמא. As Rav Soloveitchik understood the issue, if a person is performing an action in conjunction with a second process which is already operating then the result of this action is attributed to the person. In שמירת שבת כבלכתה (chapter 13, paragraph 33) Rav Neuwirth zt"l permits in cases of great need to  plug a lamp into an electrical outlet when the current is off so that when the Shabbat clock turns the current on the lamp will provide light. In note 115 he says this is a  גרמא which is permitted. Rav Soloveitchik zt"l ( as reported by Rav Shechter שליט"א) would say that this is absolutely forbidden. The electrical system is already operating and the current will come back on. The fact that now the current is off does not create the necessary "separation" between the actions of the person plugging the lamp into the socket and the current which will cause the lightbulb to glow.[1]

    However, in Israel many of the rabbis who are active in the field of designing electrical devices for use on Shabbat accept the rulings of Rav Auerbach zt'l and his student Rav Neuwirth zt"l regarding גרמא. Most of the upcoming classes will focus on innovations which rely on their definition of גרמא.

    When we discuss גרמא we need to understand if removing an impediment is also considered an indirect cause and permitted as גרמא. We ended yesterday's class with a discussion of a  תשובהfrom  Rav Tzvi Pesach Frank zt"l . He was asked if it is permitted to open the doors and windows to a room where flowers are growing. The intention of the person is to allow fresh into his home, but of course the sunlight and fresh air also aid in the flowering of his plants. Is this permitted because his primary intention is not for the plants or is it forbidden because of "פסיק רישיה" that inevitably the plants will benefit?

Rav Frank zt"l said it is permitted because the removal of an obstacle is not  considered a positive activity.

   Next week (bli neder) will finish Rav Frank's תשובה and discuss the issue in greater detail.

Thanks to everyone who participated in the class. Stuart Fischman


[1] Paul Terman asked how would Rav Soloveitchik zt"l  explain the fact that it is permitted to line up clay pots with water with the intention  that the fire will cause the pots to burst open and so pour water on the flames. The flames exist when the pots are put into place, why isn't that analogous to an electrical current powering the clock? Rav Shechter explains that ( as I understand it) that the flames are not necessarily progressing directly towards the pots. On the other hand the Shabbat clock(like any other clock) is proceeding inexorably in one direction. The person adjusting the Shabbat clock is working with the clock, and we cannot separate his actions from the clock's motion.


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January 10, 2017 1:00PM - 2:00PM
Halachot of Electricity on Shabbat

Hello Everyone,

   Here is a review of yesterday's  class on  גרמא and  the use of electricity on Shabbat. We started with the תשובה of  רב צבי פסח פרנק זצ"ל  on גרמא and הסרת המונע. רב צבי פסח פרנק was asked if it is permitted on Shabbat to open the windows in a room where there are flowers blossoming. By allowing fresh air into the room this will aid in the growth of the flowers, and aiding the growth of  flowers is a תולדה of זורע on Shabbat. On the other hand, the purpose of opening the windows is to provide fresh air for the people in the room and there is no intention to aid the flowers.

    רב צבי פסח פרנק answered that opening the windows is removing an obstacle to the air, and the removal of an obstacle is in the category of גרמא and is permitted on Shabbat. רב צבי פסח פרנק  analyzes the subject of "removing obstacles" and גרמא. Based on Rashi's explanation of הסרת המונע  as long as there is a distance between the flowers and the window, the inflow of fresh air is not attributed to the person who opened the window (כח ראשון) rather it is a גרמא (כח שני).

    We then discussed the issue if it is permitted to adjust a Shabbat clock on Shabbat. The use of Shabbat clocks for any purpose other than lighting was opposed by Rav Moshe Feinstein zt"l . He wrote that the Sages forbade instructing Gentiles to perform work for us on Shabbat because this violates the spirit of Shabbat. The introduction of Shabbat clocks would lead to the same sort of desecration since almost all electrical appliances can be operated via external clocks or built-in timers. However many if not most Poskim permitted the use of Shabbat clocks, and as Rav Feinstein zt"l predicted, their use has expanded beyond the realm of lamps. The question arose if it is permitted to adjust the clocks on Shabbat.

   The answer to this question hinges on one's understanding of what exactly characterizes a גרמא.The Gemara's example of a permitted גרמא  is the arrangement of clay pots filled with water facing a fire. If the flames should approach the pots their heat will cause the pots to shatter and release the water which will extinguish the flames. What can we derive from this case? It would seem to be as follows. One may perform an act (arranging clay pots filled with water facing flames) with the anticipation that a second unrelated and independent act will occur ( the flames heating the pots until they burst apart) which will yield a result which the person is not permitted to achieve by acting directly (the putting out of the fire).

    This is what the שמירת שבת כהלכתה writes about changing the settings of a Shabbat clock:[1]

יש לכוון ולסדר לפני שבת את שעון-השבת לשעות הרצויות להפסקת זרם החשמל או לחיבורו.

שעון-שבת שהיה מכוון מבעוד יום* להפסיק את זרם החשמל בשעה מסויימת, מותר(צח) לעשות בשבת את הדרוש(צט) כדי שיפסיק בשעה מאוחרת יותר(ק), אבל אסור להביא לידי כך שיפסיק את זרם החשמל בשעה מוקדמת יותר(קא).

וכן אם היה השעון מכוון לחבר את זרם החשמל בשעה מסויימת, מותר לעשות כדי שיחבר את הזרם מאוחר יותר(קב), אך לא כדי שיחברו מוקדם יותר(קג).

יש לכוון ולסדר לפני שבת את שעון-השבת לשעות הרצויות להפסקת זרם החשמל או לחיבורו.

שעון-שבת שהיה מכוון מבעוד יום* להפסיק את זרם החשמל בשעה מסויימת, מותר(צח) לעשות בשבת את הדרוש(צט) כדי שיפסיק בשעה מאוחרת יותר(ק), אבל אסור להביא לידי כך שיפסיק את זרם החשמל בשעה מוקדמת יותר(קא).

וכן אם היה השעון מכוון לחבר את זרם החשמל בשעה מסויימת, מותר לעשות כדי שיחבר את הזרם מאוחר יותר(קב), אך לא כדי שיחברו מוקדם יותר(קג).

   The book שמירתשבת כהלכתה is based on the ruling of רב שלמה זלמן אויערבאך זצ"ל.He held that an electrical circuit controlled by a Shabbat clock is a גרמא  environment. When the current is off one may arrange the pins which set the on/off times because this action is inherently innocuous. The pins themselves do nothing until the current arrives, just as the clay pots filled with water do nothing until the flames arrive.

   There were Poskim who objected to this ruling. Rav Moshe Feinstein zt"l said it is forbidden to tamper with a Shabbat clock at all and that some adjustments may actually be חילול שבת מדאורייתא (חלילה).  We saw last week that Rav Soloveitchik zt"l also objected to making changes in a Shabbat clock saying that it is not at all a גרמא system.

    The disagreements over what constitute a גרמא appear in the Shulchan Aruch itself. The מחבר writes that if someone wishes to light a candle on יום טוב but does not wish for it to burn completely, she may immerse the candle in a container of water prior to lighting it. The height of the water will determine how long the candle will burn. However once the candle is lit this may not be done. Many Poskim ask, "Why can't the candle be placed into the water after it had been lit?"  The placing of the candle into the water is apparently only a גרמא and גרמא can be performed to prevent loss (in this case the loss of the candle). The commentators explain that the מחבר feels that one of the conditions of גרמא  is that the object which one wishes to affect (in this case, the candle) may not be directly handled. Other Poskim do not recognize this as a necessary condition and permit placing the candle into water after it has been lit. Rav Neuwirth zt"l ( the author of שמירת שבת כלכתה) acknowledges this issue. He distinguishes between the   adjustment of a Shabbat clock (which he permits) and a seemingly similar activity which is forbidden. It is forbidden to place cold food on top a stove which is not lit, with the anticipation that a non-Jew will come later and light the stove. Why is this not permitted as a גרמא? The placing of the food on the stove before the stove is lit is an innocuous act. The arrival of the non-Jew is totally unrelated to the action of the Jew; this should be a permitted גרמא. Rav Neuwirth explains that in this case the placing of the food on the stove is not a גרמא because the object of the גרמא is being handled directly by the Jew.

   I wished today to show the complexity of the subject of גרמא. Any manipulation or adjustment of electrical devices on Shabbat should only be done after consultation with a rabbi whom one trusts.

    Thanks to everyone who participated in the class. Stuart Fischman



[1] The entire discussion of Shabbat clocks appears in chapter 13 of שמירת שבת כהלכתה.


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January 17, 2017 12:55PM - 1:55PM
Halachot of Electricity on Shabbat

Hello Everyone,

   In yesterday's shiur we studied more aspects of גרמא. We have seen that the Gemarah distinguishes between "work" which is forbidden on Shabbat and גרמא which is permitted. The Gemara's example of גרמא is to line up in the path of flames clay pots filled with water. When the flames reach the pots their heat will shatter them, the water will spill out and put out the flames.

    The question that we need to answer is how to apply the Gemara's example of גרמא to electrical circuits. What are the parameters that create a גרמא system? The way to arrive at these parameters is to examine actions which the Gemarah prohibits despite their resemblance to the גרמא of the clay pots. The גרמא of the clay pots is in masechet Shabbat page 120b. On page 47b of the same masechet there is another suggyah that also deals with putting out flames. The Gemarah on 47b prohibits the placing of an open container of water beneath a lamp to catch any sparks which may come off from the flame, thus preventing a fire.

    The question is why isn't the placing of the water beneath the flame considered a גרמא? If the essence of גרמא is the absence of direct action, then here there is no direct extinguishing of any sparks.

    Another difficulty regarding גרמא is a suggyah on page 120a in Shabbat. Rav Yehudah extends the notion of גרמא and in a case where one end of a garment has caught fire he permits pouring water on the other end of the garment to protect it from the flames. The רי"ף  rules thatגרמא  is permitted but does not mention the ruling of רב יהודה at all, the implication being that he does not accept it. The Ramban remarks that it  is puzzling that the רי"ף  rejects Rav Yehudah's גרמא.

   Having seen these suggyaot we studied an essay by Rav Elyashiv Knohl in תחומין who explains the various interpretations of גרמא .

   Rashi and Tosafot on page 47b explain why the container of water is not גרמא while pots of water are גרמא.

    Rashi emphasizes that in the case of the clay pots the person is not involved in the release of the water. This is done by the flames. In the suggyah on 47b the person has placed an open container beneath the lamp to catch the sparks. There is no "intermediary" in this situation so the action of extinguishing the sparks is attributed to the person. According to Rashi, therefore, גרמא is a system in which the action/מלאכה is performed by an outside agent.

   The Tosafot on page 47b have two explanations for the prohibition of placing an open container of water beneath a lamp. Their first explanation is that actually this is aגרמא  and as such would be permitted. The suggyah is concerned with the possibility that the person may move the water to catch a spark and because of this concern the Mishnah prohibits the open container of water. It would seem that according to this explanation all indirect activities are גרמא  and permitted (barring any other concerns). The Tosafot go on to quote Rabbeinu Tam and Rabbeinu Chananel who have a different explanation. They point out that in the case of the clay pots the fire is not extinguished immediately. The flames need to heat the pots until they shatter and only then is the water released. In the case of the open container the sparks are extinguished immediately. It follows that a גרמא  system is a system for indirect action which cannot act immediately. The Tosafot explain that Rav Yehudah permits pouring water on the edge of the garment which is burning at its other end despite what the Mishnah prohibits on 47b because in Rav Yehudah's case the water has been absorbed by the garment and is no longer visible.

   The Ramban, as we saw explains the position of the רי"ף who permits גרמא but does not permit pouting water on to the garment which is on fire. According to the Ramban/רי"ף the essential feature of a גרמא   system is uncertainty. When it is clear that an event will occur despite the fact that the action is indirect it cannot be considered a גרמא. The sparks will fall down and once a garment catches fire at one end the flames will proceed to consume the entire garment. However, if there is a fire at one end of a room there is no such certainty as to whether the flames will go in one direction or another. That is why it is permitted to line up clay pots at one location as a גרמא  activity.

    Rav Knohl's essay in תחומין addresses the issue of walking in spaces which are scanned by motion detectors. When these motion detectors are activated they respond either by illuminating the area, opening doors or other responses which are usually accompanied by flashing LED lights. Rav Knohl concludes that it is difficult to say that these circuits as constructed meet the Halacha's definition of גרמא. Nonetheless it may be permitted to walk in these areas because of a different consideration. Rav Knohl cites the opinion of Rav Wosner zt"l of Bnei Brak who said that for an activity to be prohibited on Shabbat it needs to meet two criteria:

a) it has to be one of the 39 [1]מלאכות

b) the person's action needs to be such that it would be viewed as "work."

In the case of walking into a space where there are motion detectors the act of walking cannot be considered to be "work." It is inherently innocuous. Therefore Rav Wosner ruled that a person may walk down a street where motion detectors activate lights.[2]

   Basing himself on Rav Wosner's ruling, Rav Knohl holds that:

a) one may walk down a street even though motion detectors will activate lights

b) if one needs to enter a building which has automatic doors he should not walk towards the door so that it opens for her.[3] If however a person finds herself in a place where waiting for someone to open the door for her is dangerous or otherwise anxiety producing Rav Knohl says she may walk towards the automatic door because it is at most a Rabbinic prohibition and this can be viewed as a גרמא.

   Thanks to everyone who participated in the shiur. Stuart Fischman.


[1] And we have already seen the opinions regarding the question if activating an electrical circuit is a מלאכה

[2] I hope to review Rav Wosner's תשובה  with you next week.

[3] We have seen that Rav Rabinowitz of Maaleh Adumim permits this.


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January 17, 2017 1:05PM - 2:05PM
Halachot of Electricity on Shabbat
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January 24, 2017 12:55PM - 1:55PM
Halachot of Electricity on Shabbat
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January 31, 2017 12:55PM - 1:55PM
Halachot of Electricity on Shabbat
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February 7, 2017 12:55PM - 1:55PM
Halachot of Electricity on Shabbat
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February 14, 2017 12:55PM - 1:55PM
Halachot of Electricity on Shabbat
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