6168– A Real Halacha Computer Brain? -
Q. Hon. Rabbi. Due to my father’s difficult health paralysis condition, reading on line, I became aware that new technology, known as brain-computer interface or BCI, enables users to interact with computers via brain activity or “thinking” only. One use of BCI is to enable people with paralysis and other disabilities to control robotic arms or other devices by thinking about such actions.
While it seems like science fiction, the wiring together of brains and computers is actually a reality and companies have invested millions of dollars in developing this area. It is very likely that one day our brains might be able to interact with our smartphones or tablets—and we will be able to turn an oven or light switch simply by thinking about it.
My question is can one theoretically fulfill a mitzvah simply by thinking about it? Conversely, can one violate Shabbat by merely thinking about doing a forbidden act?
A. In a BCI (brain-computer interface ) world, is “thinking” defined as “doing”? The well-known Shabbat zemer “MahYedidut”states, “Chafatzecha assurim, v’gam lachashov cheshbonot hirhurim mutarim, ul’shadeich habanot—[On Shabbat] your non-Shabbat desires are prohibited, as is performing business calculations, but pleasant thoughts are permitted, even making matches for the daughters.”
The question is—what types of “thoughts” are permitted on Shabbat?
Poskim write that there are several Torah sources which define thought. One such source is found in Tosafot in Masechet Gittin 31a, which discusses separating terumot and ma’aserot (tithes) by “thought” on Shabbat. Can one actually separate terumot and ma’aserot simply by thinking about it? Is thought considered an action? There is a machloket in Acharonim on how to understand this Tosafot. According to Rabbi Shlomo Zalman Auerbach it is forbidden to separate terumot and ma’aserot in this manner [on Shabbat]. Thus, according to his view, thought is equivalent to action. Based on this, I don’t think BCI would be permitted for general use on Shabbat; however, if we’re talking about an individual who is paralyzed and BCI can enable him to move his limbs on Shabbat, perhaps there is room for discussion.
Rabbi A. Bartfeld
Reviewed by: Hagaon Rav Shlomo Miller Shlit'a
Published: November 6, 2026