Diapers With Disappearing Ink

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diapersby R. Daniel Mann

Question: Is it permitted to use on Shabbat a diaper with forms on the outside that disintegrate when the diaper is soaked, alerting parents to change the diaper?


Answer: There is a Torah-level violation to erase (mochek)writing or, according to many, a picture or figure (see Shulchan Aruch, Orach Chayim 340:3; Beur Halacha to 340:4). When the erasure does not serve a positive purpose such as enabling new writing, the violation is only Rabbinic (Mishna Berura 340:17). Thus, the diapers in question would seem to have no more than a Rabbinic prohibition. Another possible reason for no Torah prohibition is that the erasure’s result may be “destructive” (mekalkel). It is debated whether considering the side benefit, that the disintegration provides desirable information, it is mekalkel (see Beur Halacha to 340:13).

The main cause for leniency relates to who and how the erasing is done. Directly, it is the baby who erases by urinating, but he is almost always too young to require training in Shabbat prohibitions. Although one must not “feed” children prohibited matters, he may allow a situation in which a baby might choose to do a forbidden action (see Yevamot 114a). Here it is even better, as the baby “violates” Shabbat without any knowledge of this consequence of his action, in which case it is not a fundamental Shabbat violation even for an adult (see Shut Rabbi Akiva Eiger I:8).

Thus, the question is whether the adult violates Shabbat by creating a situation in which a future event will set off a melacha. Specifically, putting the diaper on the baby creates a situation where erasure will occur. When the direct cause (urination) of the erasure has yet to occur at the time of the adult’s action (diapering), we say that the adult acted through gerama (indirect action). Violation of Shabbat through gerama is a very low level violation of Shabbat, to the extent that it is permitted in certain cases of need (Rama, OC 334:22).

In this case, there are often additional points of leniency. For parents who are not interested in the erasure, as they can easily determine the “old way” when the diaper is soaked, the erasure is permitted as a davar she’eino mitkaven (an unintentional forbidden result of one’s action) of the diapering. It is true that when the forbidden result is a definite outcome (psik reishei), the action is forbidden by Torah law (Ketubot 6b). However, when the result is arrived at through gerama, many important poskim permit psik reishei (Shemirat Shabbat K’hilchata 12:18, based on Rav Auerbach; see discussion in Orchot Shabbat 29:(41)). Some say that gerama is permitted in cases where direct action is only Rabbinically forbidden. Other opinions disagree, and in any case the leniency likely does not apply to every Rabbinic prohibition (see Yabia Omer III, OC 17). Yet the above is probably not needed, as, in actuality, the erasure is not a psik reishei. For a variety of reasons, including the baby soiling with solids before the diaper is soaked, diapers do not always reach the point that forms are erased.

When there are not meaningful figures of letters but just a line or dots, there is even more room for leniency, as erasing such nondescript things is not a (full) violation of mochek unless the erasure uncovers or enables writing (see Shulchan Aruch, OC 340:3; Orchot Shabbat 15:59). We find this distinction in such cases as cutting cake with writing or clear figures vs. nondescript shapes (Rama, OC 340:3).

One may generally use diapers with disintegrating ink (Orchot Shabbat 15:52). However, note that many of the reasons for leniency are based on the assumption that one does not have intention when diapering for the erasure, which is a valid assumption when one did not intentionally buy diapers with this marginally useful feature. However, for one who values this function, use of such diapers on Shabbat may very well be forbidden and should be avoided. (Regarding a slightly stricter case of a color-changing strip, see the Star-K website, which has a similar ruling to the above.)

About Daniel Mann

This column is produced on behalf of Eretz Hemdah by Rabbi Daniel Mann. Rabbi Mann is a Dayan for Eretz Hemdah and a staff member of Yeshiva University's Gruss Kollel in Israel. He is a senior member of the Eretz Hemdah responder staff, editor of Hemdat Yamim and the author of Living the Halachic Process, volumes 1 and 2 and A Glimpse of Greatness.

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