[Avodah] Fitbit on Shabbos

[Micha Berger via Avodah]

On Thu, Mar 31, 2016 at 09:28:35PM -0400, Akiva Miller via Avodah wrote:
: I think the real difference between the two cases is how deeply one must
: dig to see the wires and the switches: In the floor mat all you'd need, I
: guess, is to cut through a centimeter or two of rubber to see the wires,
: while the motion detector would need a microscope and an engineering degree
: just to understand what you're looking at. But even with the mat, no one
: can actually see the electricity move simply as a result of standing on it.

I think those two are different in kind.

In the floor mat, a hypothetically visible (really, we should use the
more generic sensible, and not just talk about one sense) change occurs.
It just happens that situationally, we can't see it.

Let's say there was an unlit room at the end of a long hall, so there
was no way to light it without chilul Shabbos. Would it be mutar to
write in such a room? Or is writing assur, regardless of the situation?

If a bug is born of eggs that are large enough to be visible, but happen
to be hidden within uncut meat, is the maggot kosher?

In the motion detector (or the fitbit), the change is not detectible
by an unaided human, regardless of the situation. People cannot see
the microscopic. (And yes, I realize that claim is true by definition
of the word "microscopic"). The change is outside the realm of unaided
human senses in principle, not in situation.

If one looks through water through a microscope and finds water bears
and other micrscopic bugs in it, does that water become treif? Is all tap
water or distilled water in bottles that were open too long treif because
one in theory would find such things in most water? (For a moment there
I thought about mayim she-lanu, but then realized this would be a much
more restrictive issur than that.)

: There seems to be an idea that Hilchos Shabbos ignores invisible actions,
: but in my experience this idea is very new. Not even ten years old perhaps.

Rav Dovid Lifshitz spoke about halakhah in general ignoring the microscopic
some time between Sep 1984 and Jun 1986.

The permissability of killing bugs that have no piryah verivyah on Shabbos
(or of eating them) is miSinai. Or at least, as old as some pre-Chazal
rav pasqened the deOraisa that way, since Chazal take it for granted.

The real motive for saying halakhah only applies to the sensible is to
find a new explanation for an old heter to avoid saying a din deOraisa
is in error, even though the old explanation (abiogensis of these insects)
was shown to be empirically false.

:-)BBii!
-Micha

-- 
Micha Berger             Rescue me from the desire to win every
micha at aishdas.org        argument and to always be right.
http://www.aishdas.org              - Rav Nassan of Breslav
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