Imagine if a new technology enabled all 39 melakhot to be done on Shabbat without violating any existing halakhic prohibition. How should our poskim respond?
Discussions of halakhic innovation often revolve around an asserted need for new leniencies. But it stands to reason that changed circumstances will require just as many new stringencies, and that the authority to make changes must apply both ways. If today’s halakhists are judged incompetent to issue new stringencies, they are unlikely to succeed in implementing new leniencies.
Rabbinic gezeirot function to “build a protective fence” around the Torah by forbidding actions that might lead to violations of Torah prohibitions. New circumstances yield new threats and require new gezeirot. However, in Yabia Omer 1:16, Rav Ovadiah Yosef zt”l writes, “It is well known that our teachers the rishonim and aharonim have stated broadly that we may not decree gezeirot based on our own judgment.” Rav Ovadiah cites six sources to directly substantiate this principle. My purpose here is to reopen the discussion based on an analysis of those sources and to compare Rav Ovadiah’s approach with that of Rav Moshe Feinstein zt”l.
Rav Ovadiah addresses the issue of whether to forbid reading by the light of an electric lamp on Shabbat. The Mishnah (Shabbat 11a) teaches that one may not read by the light of an oil lamp. The Talmud explains (Shabbat 12b) that the concern is lest one violate the prohibition against kindling by tilting the lamp to improve its draw. This concern plainly does not apply to electric lamps. Therefore, the gezeirah does not apply to reading under electric lamps, just as reading by the light of fireplaces is permitted. However, because electric lamps can be turned off very easily, one can argue plausibly that reading by them should be forbidden, and that the Talmudic rabbis would have forbidden this had such lights existed in their time.
Rav Ovadiah’s first source regarding the appropriateness of new gezeirot is a responsum of Rabbi Israel Bruna (Shu”t Mahari Bruna #108), one of the leading poskim of fifteenth-century Germany. Mahari Bruna discusses whether a woman who immerses while wearing a loose ring on her finger is permitted to resume intimacy with her husband. Immersion is valid only if the water can reach all the woman’s skin, and the concern is that if we permit loose rings, women will come to wear tight rings that obstruct the water’s access. He notes that Ramban and Rashba disagreed about whether halakhah requires removal of a loose ring in advance (lekhathilah) of immersion, but he asserts that “after the fact (bediavad), no one disputes that from the day that the Talmud was sealed, no gezeirah was initiated that we do not find in the Talmud, as Rabbeinu Asher (Rosh) wrote in Shabbat Chapter 2 regarding the ‘convulsion of the Geonim.’” Because the Talmud did not ban immersion with a loose ring, Mahari Bruna rules that the woman is permitted to resume intimacy with her husband.
Yet I am puzzled by Rav Ovadiah’s citation of this responsum with regard to electric lamps. A decree against reading by electric lamps declares that something should not be done; it does not invalidate something that has been done. It is therefore parallel to a decree against immersing while wearing a loose ring. Since Mahari Bruna is open to prohibiting women from immersing with loose rings, even though the Talmud did not, he should therefore also be open to prohibiting reading by electric light.
Mahari Bruna’s distinction between an initial decree (lekhathilah) and invalidating a ritual after the fact (bediavad) also seems inconsistent with the Rosh he cites as support, which is also Rav Ovadiah’s second source.
Rosh (to Shabbat 2:15) cites the Geonim as follows: “We do not practice saying [a berakhah specific for fast days] in the evening [amidah], or even in the morning [amidah], lest he be seized by illness or convulsion and eat something, making it turn out that he was a liar in his prayer.” Rosh responds: “I am astonished: How could the Geonim initiate a gezeirah after Rav Ashi sealed the Talmud?!” The issue here is lekhathilah – should one or shouldn’t one say the berakhah? This is parallel to forbidding immersion while wearing a loose ring, and it is not parallel to invalidating an immersion after the fact. The Geonim presumably did not decree that one who says the berakhah must repeat the amidah. I am therefore at a loss to explain why Mahari Bruna cites Rosh as supporting his claim that post-Talmudic rabbis are restricted only from making bediavad decrees.
Regardless, Rosh seems to support Rav Ovadiah’s principle by stating an absolute rule against new decrees, albeit implicitly conceding that the Geonim rejected this rule. However, we can interpret Rosh’s rule more narrowly. Rosh and Mahari Bruna both deal with decrees that apply to situations already considered by the Talmud. The question before them is whether to initiate a prohibition when, facing the same circumstances, the Rabbis of the Talmud chose not to prohibit. Rosh’s rule may therefore be irrelevant to the issue of whether post-Talmudic authorities can make decrees in response to entirely new circumstances, such as electric lamps.
This distinction between precedented and unprecedented circumstances emerges clearly from Rav Ovadiah’s third source, Radbaz’s commentary Yikar Tiferet to Rambam (Hilkhot Terumot 1:22). Radbaz discusses a dispute between Rambam and Raavad as to whether grains grown outside the Land of Israel become rabbinically obligated in terumot and ma’asrot when brought to Israel. Radbaz explains that Rambam held that “we should not initiate gezeirot based on our own judgment, since [such a decree] is not mentioned anywhere. Indeed, in the Yerushalmi they discussed this Mishnah at great length and never mentioned [the possibility] that [these grains] would be rabbinically obligated!” Radbaz explicitly frames Rambam’s argument against such a decree in terms of acting where our predecessors chose not to.
Rav Ovadiah’s fourth source, Maggid Mishneh (to Hilkhot Hametz u-Matzah 5:20), similarly addresses whether later rabbis can make new decrees when addressing the same circumstances as their predecessors. He understands Rambam as permitting the baking of matzot with oil or wine or honey added to the dough, because the combination does not rise faster than a dough with only water in it. Raavad limits this permission to zerizim (people eager to fulfill mitzvot punctiliously), but he forbids it to ordinary folks. Maggid Mishneh responds on behalf of Rambam: “But I say: We may not decree gezeirot based on our own judgment.” People certainly considered baking with these additives in the time of the Talmud.
Similarly, Rav Ovadiah’s fifth source, again from Radbaz (Shu”t Radbaz 1:149), also addresses a case of unchanged circumstances. Radbaz there considers whether a woman who experiences a hargashah (sensation associated with becoming niddah), but then inspects herself and finds no blood, should be considered a niddah under Rabbinic law. He responds that “we should not initiate gezeirot based on our own judgement in circumstances where our predecessors did not decree.” The phenomenon of hargashah without finding blood of course also existed in Talmudic times.
Note that Radbaz and Maggid Mishneh each introduce the rule against new gezeirot to explain why Rambam permits where Raavad forbids. This suggests that Raavad (like the Geonim cited by Rosh above) may not agree with even our narrow understanding of the rule, and he might permit making new gezeirot even when circumstances have not changed significantly.
However, Rav Ovadiah’s sixth source, Rabbeinu Nissim [Ran] (cited in Shu”t HaRivash #390), at first glance supports the claim that we cannot make new decrees even in response to new circumstances. Ran responds to a rabbi’s request that he ban a community’s practice of announcing real estate sales at Shabbat davening. These announcements served the public policy purpose of establishing a presumption of legitimate ownership (if no one came forward to contest the sale). This public good certainly suffices to override the general prohibition against speaking of business matters on Shabbat. Ran notes, however, that the Mishnah (Beitzah 36b) forbids batei din (halakhic courts) from adjudicating on Shabbat even in cases of public need, lest they come to write. Shouldn’t the same consideration forbid this practice? Ran responds that we should not extend that prohibition to this case “because we only have those [gezeirot] listed by Chazal, and we should not originate gezeirot on our own.” Here is a new practice, and yet Ran rules out making a new gezeirah.
Yet the key phrase here is “those [gezeirot] listed by Chazal.” To what list is Ran referring? Rabbinic literature contains no comprehensive list of gezeirot that we can check to see if it includes a decree against announcing real estate sales on Shabbat. Rather, Ran must be referring to the Mishnah in Beitzah (36b), which includes a list of activities prohibited on Shabbat and Yom Tov despite their being “something of a mitzvah” (reshut), among them the convening of a beit din. The Talmud (ibid 37a) identifies writing as the concern behind the prohibition. Ran explicitly classifies these announcements as reshut. His argument against banning these announcements is that the Mishnah intended its list to be exhaustive, and therefore with regard to the specific question of banning a reshut that might lead to writing, “we only have those [gezeirot] listed by Chazal.” This argument has no relevance to a general rule against new decrees.
Thus, none of Rav Ovadiah’s six sources explicitly supports a rule against initiating new gezeirot in unprecedented circumstances, and several of them implicitly acknowledge that the Geonim and Raavad allowed new gezeirot even in precedented circumstances. Nevertheless, a broader restriction against new prohibitions may have developed after Radbaz. Such a development may be revealed in the many sources that Rav Ovadiah cites later in his responsum. Moreover, there may be practical reasons making such decrees impossible today. For example, making gezeirot might require a degree of public acknowledgement and deference that is not given to any contemporary halakhist or group of halakhists.
Rav Moshe Feinstein (Igrot Moshe OC 4:50) also addresses the question of whether new gezeirot are possible in response to new circumstances. His concern is not electric lamps, but rather the potential of electric timers to completely transform the Shabbat experience: “It is obviously forbidden to permit this, because via such timers one could do all the forbidden categories of labor on Shabbat, and [run] all factories, and there could be no greater devaluation of Shabbat.” Rav Moshe adds, “It’s clear that had this device existed in the times of the Tannaim and Amoraim, they would have forbidden this.”
Rav Moshe is less certain “that we cannot forbid what the Sages did not forbid, and that one may not derive further prohibitions from their decrees, even against things that are rationally more stringent.” Even if we cannot, he insists that anything not prohibited by Hazal, “even though this was because the case didn’t exist in their time, and thus there is no actual prohibition, nonetheless one should not permit it, since it is something that it would be appropriate to forbid.” The circumlocutions in this responsum are striking and astonishing: “forbidden to permit,” “appropriate to forbid,” and so forth. Clearly, Rav Moshe felt that something goes seriously awry when halakhah cannot effectively rebuild its fences in response to new circumstances.
The authority to issue new permissions or create new obligations is not necessarily subject to the same rules as the authority to forbid. One can construct a theoretical system that gives contemporary halakhists the authority to make new decrees freeing agunot without simultaneously enabling them to ban putting televisions on Shabbat timers. Maybe that authority could also enable regulating publicly owned corporations and responding effectively to the existence of a Jewish state. But it seems far more intuitive to connect the issues practically, and even to claim that permitting what would otherwise be forbidden requires more authority than forbidding what would otherwise be permitted. Therefore, advocates for creative halakhic legislation should recognize that the authority to issue new decrees will almost certainly go both ways, and that generating the authority to permit may require granting the authority to forbid. My hope is that this essay opens space for serious discussion of the extent to which we wish to grant that authority.
 See, e.g., Mishnah Avot 1:1.
 Raavad generally sees himself as continuing Geonic tradition, so this historical conjunction would not be surprising.
 Real estate sales existed in the time of Hazal, and therefore one might argue that here as well Hazal chose not to ban announcing them, so Ran also is not relevant to the question of new technologies. But since the practice of announcing them did not exist, this seems to me an overreach.
 The Mishnah uses the term reshut, which Rashi here defines as ketzat mitzvah (“something of a mitzvah”).
 The validity of Rav Moshe’s discomfort is independent of the question of whether one shares his intuition about the negative implications of timers for the Shabbat experience.
 For example, by distinguishing between gezeirot and takkanot.