Q&A: A Light Turned On by a Motion Sensor on the Sabbath
A Light Turned On by a Motion Sensor on the Sabbath
Question
Hello Rabbi,
Is it permitted to enter an apartment building stairwell where there is a motion sensor that turns on a light, on the grounds that this is an exempt case of unintentional involvement (mit'asek)? And if you would say that mit'asek is forbidden ab initio, in such a case is it permitted for another person to enter afterward and benefit from the light, or is it considered a Sabbath violation product (ma'aseh Shabbat)—if the first person entered intentionally—since the view of most halakhic decisors (aside from Oneg Yom Tov and Minchat Baruch) is that ordinarily there is no law of ma'aseh Shabbat in a case of mit'asek. I am asking about a case where the Sabbath violation product was brought about with awareness that it would happen, albeit in the course of another act (walking in the stairwell). What do you say?
Answer
In my opinion this is permitted even according to the side that forbids mit'asek rabbinically (Rabbi Akiva Eger’s view). A person who walks normally does not need to refrain from walking because of side obstacles that are not dependent on him. He is engaged in walking, not in turning on a light. Consequently, this also does not count as a Sabbath violation product. I seem to recall having once seen that this was written in the responsa Shevet HaLevi.
Incidentally, when they forbid mit'asek, it is obvious that they are speaking of a case where he knows the result will occur; otherwise the prohibition has no meaning at all.
Discussion on Answer
That is a very good question. Quite a number of later authorities addressed the relationship between an unintended act and unintentional involvement (mit'asek)—especially when he knows about the transgression that is brought about as he walks—and in fact your argument is not really against me but against the very distinction itself, and this is not the place for a fuller discussion. Incidentally, the difference between an unintended act and a labor not needed for its own purpose is also not at all simple.
I hear that.
So why is it forbidden to drag a bed, chair, or bench in a case of an inevitable result (pesik reisha)? After all, he is dragging it in the normal way and shouldn’t need to refrain from dragging because of side obstacles. Presumably you would distinguish and say that here they are not side obstacles—but why? In both cases, it is possible to do the act (walking or dragging) without the prohibition (walking in a place without a sensor, and dragging in a place with hard ground), and in both he caused the prohibited result directly. What is the difference?
Again, I saw in Avnei Nezer (194), and also in the Shevet HaLevi you mentioned (vol. 10, sec. 60), that they distinguished between a person dragging, etc., where the labor is done in the very body of his act, and a motion sensor. I assume that is your intention. But I do not understand: why is the furrow that is formed considered an integral part of the act of dragging, whereas activating the sensor is not?