We have seen in our past three discussions that the question of using elevators on Shabbat is the subject of an exceedingly rich debate between two Torah giants, Rav Levi Yitzchak Halperin and Rav Shlomo Zalman Auerbach. This week we will complete our review of the debate, focus on the concern of weighing mechanisms, and suggest a conclusion about the use of elevators and escalators on Shabbat and Yom Tov.
In our first discussion of this issue we mentioned Rav Halperin's concern that when an elevator carries a heavy load the motor turns into a generator and produces electricity which is fed into the power lines. Rav Halperin writes that this involves a Torah prohibition since the generator powers various machines and appliances that perform many "Melachot."
Professor Lev (Techumin 5:65-73) responds with a factual and halachic argument. He points out factually that no new current flow is created by added passenger weight. He also states that any power that is generated by the elevator is dissipated in the electric wire and is of no use.
Furthermore, even if Rav Halperin were to be correct factually, the problem would constitute a rabbinic level prohibition not a biblical level prohibition because the creation of the power is a "Melacha She'einah Tzricha L'gufa."
This term is a halachic category describing situations where one intends to perform "Melacha" but it was not his purpose to perform that Melacha. A classic Talmudic example is one who digs a hole but his intention is only to collect dirt, not to prepare the ground for planting. The Tanaim disagreed as to whether a "Melacha She'eina Tzricha L'gufa" is forbidden biblically or rabbinically (see Shabbat 93b). Although the Rambam (Hilchot Shabbat 1:7) rules that it is biblically forbidden, most Rishonim rule that it is only rabbinically forbidden (see Raavad ad. loc. and Shulchan Aruch Orach Chaim 316:8 and Mishna Berurah 316:34). Accordingly, Professor Lev argues that if indeed the elevator motor is turned into a generator which powers many machines and appliances, only a rabbinic prohibition is violated. He argues that the intention of the elevator passenger is to descend to lower floors and not to create a generator. Thus, the passenger's action can be deemed a "Melacha She'einah Tzricha Legufa."
Rav Halperin disputes this point. He argues that "the passengers require and therefore desire that power be generated by his weight and utilized, for otherwise the car speed increases without control and it is impossible to slow down and stop except by emergency measures."
Halacha L'Maaseh- A Compromise
We have seen at length that both sides of the elevator debate have presented compelling arguments for their positions. Thus, it is difficult for a halachic authority to decide which opinion to follow. It is helpful to note that (providing one accepts Professor Lev's facts and argument on "dispute number five") the entire debate is whether or not one violates a rabbinic prohibition. Moreover, Rav Halperin writes in the second chapter of "Maaliot B'Shabbat" that since the electric circuits that are completed in the course of elevator usage last only briefly ("Eino Mitkayeim") only a rabbinic prohibition is violated. If, however, the lights displaying the floor numbers are incandescent then a biblical prohibition perhaps may be involved. One may argue, on the other hand, that since these lights are turned on only momentarily then they are only "Eino Mitkayeim" and thus only a rabbinic prohibition is violated.
Accordingly, it appears appropriate to follow the decision made by Rav Shlomo Zalman Auerbach (cited in footnote 140 of Shmirat Shabbat Kehilchata chapter 23) that "one should not rebuke those who are lenient and ride on a descending automatic elevator." Therefore, one should make every effort to avoid using a descending automatic elevator and should rely on the lenient opinions only when absolutely necessary. Rav Mordechai Willig stated at a Shiur on this topic (that he delivered at Lincoln Square Synagouge in the 1990’s) that one should make every effort to move into an apartment on a low floor to avoid having to rely on the lenient opinions regarding elevators. Rav Halperin makes very compelling arguments and his opinion should be followed except in a situation of great need.
Electronic Weighing Mechanisms and Sensors
A complicating factor in this question is the presence of electronic weighing mechanisms and sensors in most newer elevators. Rav Halperin in the fifteenth chapter of "Maaliot B'Shabbat" addresses this problem. He notes that these electronic weighing mechanisms measure the weight of the passenger load and transmit the information to the control system. It informs the control system about conditions such as "passenger in car," "full load," or "overload" and other information which enables proper control of acceleration and deceleration.
Among the steps taken by both Rav Halperin's Institute for Science and Halacha (Jerusalem) and the Zomet Institute of Gush Etzion in order to modify the elevator for Shabbat, is to disconnect the electronic weighing mechanisms in elevators. These mechanisms pose a serious problem for the use of elevators that have not been specially prepared for Shabbat use. Perhaps in case of great need or in case one does not have the opportunity to research if a particular elevator is equipped with these devices one can rely on a "Sfek Sfeika," a double doubt. One doubt is that perhaps the elevator is not equipped with weighing devices and the second is that perhaps the weighing devices work through increasing current and not completing a circuit (see Maaliot B'Shabbat p.183). One should consult his Rav regarding this question. Another serious problem corrected by Rav Halperin's institute and the Zomet Institute are the sensors present on elevators. One should do his best to avoid triggering the sensors on more modern elevators.
There is one area where it seems that one may be lenient - the use of automatic escalators on Shabbat. Rav Neuwirth (Shmirat Shabbat Kehilchata 23:52) permits the use of automatic escalators on Shabbat because the concerns detailed by Rav Halperin regarding an elevator seem not to apply to escalators. This ruling is of great significance in communities such as Hong Kong where it is very difficult to get from one section of the city to another without using escalators.
Specially Designed Shabbat Elevators
Rav Halperin's Institute for Science and Halacha modifies elevators so that the passengers' weight has no impact on the elevator's descent. The Zomet Institute also modifies elevators which accommodate some of Rav Halperin's concerns such as eliminating the use of incandescent bulbs, but takes a somewhat more lenient (and far less expensive) approach to this issue. The details of how the Zomet Institute modifies elevators for Shabbat is described in Techumin 5:96-99.