Minhag Manhattan: Do I Need to Avoid Automatic Doors and Lights on Shabbat?
Many stores in Manhattan have automatic doors that open when someone approaches. On Shabbat, is one required to avoid walking close to these entrances, even when one has no intention of entering the store? Must one walk on the other side of the sidewalk, or even cross the street, to avoid activating the doors? A similar question comes up in apartment buildings with motion-activated lighting. May one walk through a hallway or stairwell knowing that lights will turn on?
Jewish law distinguishes between, on the one hand, deliberately performing a prohibited action on Shabbat and, on the other hand, doing something permissible that happens to produce a prohibited result. For example, dragging a chair across the ground might create a groove in the dirt, which is prohibited on Shabbat since it is the action of “plowing.” But if one's only intention is to move the chair, and creating a groove is not inevitable, the action is permitted. This is based on a principle known as davar she'eino mitkavein: an unintended consequence of a permitted action is permitted.
There is, however, an important exception. If the prohibited result is inevitable, we cannot disregard it just because we didn’t intend it. For example, if you know that the chair is so heavy that dragging it will certainly create a groove in the ground, then dragging it is prohibited even though you didn’t intend to create the groove. This is called psik reisha: when an action will inevitably produce a prohibited result, it is prohibited even if that result was unintended.
So if walking past a store will inevitably cause its automatic doors to open, doesn’t that make it prohibited? Not necessarily. Halakha makes another important distinction between an unintended result that benefits a person and one that does not. Consider again the example of dragging a chair across the ground. Even if doing so will certainly create a groove in the dirt, the person moving the chair may have no interest in creating that groove and derive no benefit from it. Poskim debate whether an inevitable but unwanted consequence, known as psik reisha delo nicha lei, is permitted on Shabbat. Even according to those who prohibit it, there is greater room for leniency when the resulting prohibition is itself rabbinic and not biblical.
When you walk past a store with automatic doors, you have no interest in opening them. You aren’t entering the store, and it makes no difference to you whether they open or remain closed. Furthermore, we generally treat the electronic operation of an ordinary automatic door as involving rabbinic rather than biblical Shabbat prohibitions. When we combine these two factors, namely, the absence of any benefit and the rabbinic nature of the prohibition, we can conclude that one is permitted to walk past automatic doors, even while knowing that it will cause them to open.
You don’t need to cross the street or walk around the entrance. You can simply continue walking down the sidewalk (this is different from deliberately approaching an automatic door in order to enter a building. In that case, you actually want the doors to open in order to walk through them).
The same principles apply to motion-activated lights in apartment buildings. Here, too, the relevant question is whether one benefits from the additional light. If a stairwell already has enough permanent lighting to navigate it safely, and additional LED lights turn on as one walks through, the additional light provides no necessary benefit. But if the stairwell would otherwise be dark, the situation is different. Now the lights are providing a benefit, and all the above reasoning does not apply (There is also a distinction between different types of lighting. Traditional incandescent bulbs have burning filaments that involve biblical Shabbat prohibitions, whereas we can treat most LED lighting much more leniently. The discussion here assumed LED lights).
In short, Halakha does not require us to avoid every electronic sensor on Shabbat. When the resulting action is prohibited only rabbinically and provides us no benefit, there is room for leniency. We may walk past automatic doors without taking a detour, or use an otherwise illuminated stairwell even if additional LED lights turn on.
