שבת לייט סוויטש
ווען מ'רוקט ארויף אדער אראפ דער סוויטש טוט מען גארנישט עלעקטראניקלי, מ'רוקט בלויז א פלעסטיג, וואס איז בכלל נישט פארבינדען צו קיין עלעקטער דראטען. דער סוויטש האקט פשוט איבער די סיגנאל'ס וואס איין זייט שיקט צום אנדערע זייט.
The technologist’s analogy:
There are two robots, “Jake” and “Ben”. Jake is located outside a room, and Ben is inside that room. The robots are usually “asleep” or inactive/dormant.
At random intervals, Jake will send a message to Ben using a brief pulse of light from its flashlight.
Ben looks for these messages, and will act upon them. If it sees a pulse, it will turn the light in the room on (or leave it on). If it doesn’t see a pulse, it will turn the light in the room off (or leave it off).
Jake has a way of indicating that it’s getting ready to send a message. Its eye color is constantly changing between green (for a random duration), then red (for ~5 seconds), and then back to green. It will only send a message right before its eye color changes from red back to green. So when its eyes are green, there is absolute assurance that no message will be sent for at least another ~5 seconds, even if the change to red is imminent. Jake is dormant during the entire time that its eyes are green and red, and will only wake up at the very end of its red-eye phase, send its message using a pulse from its flashlight, then go back to green eyes and be dormant again.
At each attempt, there is a possibility that the message communication will fail: Jake’s flashlight may break, and Ben may not receive it. The probability of failure is random, within a certain range.
At each attempt, there is also a possibility that Ben will fail in turning the room light on/off as expected, even if the message was received properly. The probability of failure is random, within a certain range.
On Shabbat, a person opens/closes the door to the room separating the robots, while Jake’s eyes are green, knowing that it will ultimately affect the state of the room light… Welcome to KosherSwitch®.
An alternative Talmudic analogy:
There is a candle burning next to a closed window, and a strong wind blowing outside. Certainly, opening the window on Shabbat is forbidden, since the candle will be extinguished immediately.
There is a device that can determine if there’s no wind currently blowing, and it can predict with 100% accuracy that no wind will be blowing for at least the next ~5 seconds. It lights up with a green light when it has determined this to be true.
On Shabbat, a person opens/closes the window while the device’s indicator is green, knowing that a wind will ultimately blow and succeed in extinguishing the candle.
More accurately: A person opens/closes the window before the wind is created, before the candle is placed by the window, at a time when the device’s indicator is green, knowing that sometimes gusts of wind hit the candle [its future location] and sometimes they miss, and even when they do strike the candle, sometimes they’re able to extinguish it, but other times they do not… Welcome to KosherSwitch®.