[Avodah] shabbas//mishum eiva, etc???

[Chana Luntz]

> could someone please explain to me the process of how and why and when
> the chachamim are allowed to enact, or go around, clear midoraisa
> guidelines???

Your question is much wider than the title of the posting would suggest -
and in fact what you need is a book to answer this, not anything that can be
done justice to in a posting.  In such a book, here are some of the chapter
headings you would need:

a) a discussion of the differences between d'orisa asehs (positive
commandments) and lo ta'asehs (negative commandments).  The former is much
easier to "enact or go around" than the latter on the basis that telling
somebody to shev v'al ta'aseh (sit and not do something) is very different
to telling them to act to violate a prohibition.  An example of an enactment
vis a vis d'orisa aseh is the rabbinical prohibition on blowing shofer on
shabbas

b) once you are in the realm of aseh's the gemora in Brachos 19b- 20a seems
to suggest that the principle of kovod habrios allows you to shev v'al
ta'aseh even for a aseh d'orisa.

c) even where you are talking about lo ta'asehs, "going around" is often not
considered a problem.  Of course the most famous case of going around is
prozbul, ie a going around of the requirement to cancel personal loans in
shmitta, but similarly sale of chametz (which is clearly preventing the
violation of a negative prohibition) is another.

d) When we are talking about monetary matters, there are other reasons to be
lenient.  As well as the aforementioned Brochos 19b suggesting that there
are exceptions for kovod habriyos vis a vis monetary matters, there is a
general principle of hefker beis din hefker, that beis din has the power to
take away somebody's property that they own on a d'orisa level and give it
to somebody else.  A classic case of this is making found objects the
property of minors, where they would not be on a d'orisa level.

e) another principle which is invoked periodically is eis la'asos - the idea
that there may be times when chazal are specifically empowered to violate
d'orisas. While mostly this is seen as only applying for limited situations
and time periods, eg Eliyahu sacrificing on har carmel, outside the beis
hamikdash, which is a one off, there is of course the writing down of Torah
She Ba'al Peh, which would seem to be, or have the effect of, extending
throughout time.

f) there are also specific areas where the chachamim have been given powers.
One of these is, for example, kiddushin, on the understanding that kiddushin
takes place according to the daas of the rabbanan and therefore (at least in
limited circumstances) they have the power to annul the kiddushin.  There
are other areas where at least certain rishonic and achronic understanding
are that the chachamim were given powers to legislate that effectively make
d'orisas, such as in relation to shiurim.

> eg, mishum eiva saving an aino""yehudi, etc, {or is that not a
> midoraisa???};?

Your heading refers specifically to shabbas here, but this question appears
to be even more general than shabbas.  Outside of shabbas, I'm not sure that
such saving would violate any d'orisas, moridin v'ain ma'alin (if it applies
at all to people today) does not seem to be a d'orisa, the only d'orisa
would seem to be in relation to the seven nations.

Once you get into d'rabbanans, then there are a whole host more principles
that clearly permit or override or where the chachamim were not gozer in the
case of, or were gozer in the other direction contradicting, d'rabbanans.
Mishum Aiver is one of them, but there are lots of others, everything from
hefsed merubah, b'mkom tzar etc etc.  Again all of these overreaching
principles have rules and applications where they are used, which is why you
need a book.

If you are talking about shabbas specifically, then I would agree with RZS
here that the real underlying principle is pikuach nefesh.  We push aside
even d'orisas where there is even a remote safek of pikuach nefesh, and it
is the characterisation of the result of the aiveh leading to pikuach nefesh
risks that allows for d'orisa shabbas violations where there is no
alternative.

Regards
Chana