[Avodah] Chezkas Kehuna

[jew at when.com]

"Doesn't this reverse cause and effect? We allow kohanim to duchen
because we don't posit a safeiq unless we have reason to. That's what
chazaqah means -- we presume that this case follows the rule of thumb.
(Technically that's what the Sheiv Shemaatsa would call a chazaqah
disvara, in distinction to a chazaqah demei'iqara.)" 

I think you are confusing the chazaka itself with the validity and the
validity of the validity of the chazaka; I was attacking the validity
of the validity of the chazaka and not chazaka itself or the validity
of the chazaka.

"We allow kohanim to duchen because we don't posit a safeiq unless we
have reason to."

This is false; we allow kohanim to duchen not because we do not posit a
safek unless we have to but rather because they have a father who duchend
in conjunction with the fact that he would not have duchened if he was
not permitted to duchen; a chazaka AND it's stipulated requisites.

For instance, if an eiruv is up before shabbos we assume it is up
during shabbos. This, in part, is because of a "status quo chazaka"; the
assumed negation of change. According to many, kohanim also have this
type of chazaka. However, all poskim agree that the assumed negation
of change exclusively is not sufficient. The eiruv is only considered
kosher consequent to mainly the presence of x, y and z:

x: two kosher aidim who testified that the eiruv was up at a certain
time prior to shabbos.(validity of the chazaka)

y: non-existence of a certain level of bad weather subsequent to x
(validity of the validity of the chazaka)

z: assumed negation of change ("Status quo chazaka" - this is the most
common type of chazaka. If something was one way then we assume it remains
that way. Like we can assume the eruv is up since we know it was up when
Shabbos started. Of course certain things can weaken the chazaka or ruin
it but in general we assume the status quo remains. Rov is stronger than
this type of chazaka"). So it seems to be the the chazaka is a negation
of change, and the other requisites consist of validating the origin
and ensuring perpetuity of this negation of change.

Kohanim, as I have understood it, are considered kosher kohanim consequent
to the presence of mainly u, w, x, y, z and the non-presence of t:


w: the assumed non-existence with regards to the vast majority of people
to ACTIVELY lie about being kohanim ( i.e. initially SAYING that you
are a kohen when you are not.

[w differs from the likelihood of] "t": which is a lie resulting from
the passive non-disclosure of information (i.e. having relations with a
non-Jew in college and NOT saying that you did; especially after marriage.

x: the performance of the act of duchening by the father of the kohen
(the validity of the chazaka)

y: assumed negation of change.(the status quo chazaka)

z: the non-existence of x (this completely differs from a subsequent
negation of x) in cases where x is not halachically permitted (that
we have an enormous amount of chalalim or potential chalalim who have
duchened). (this is the validity of the validity of the chazaka) (z is
the reason why (no pun intended) x is accepted).

u: the non-presence of a "probability chazaka" (living in a secular
college when not religious or dating a non-Jew for a significant period
of time) that would take precedence over the chazaka of y ("Probability
chazaka- Something happens this way almost all the time so we can assume
it happened this way. That's the type of chazaka we're talking about in
our gemara. Talmidei chachamam almost always take off trumos and maasros
right away so we can assume it happened here also; pesachim 9a")

According to the Rabbi I spoke to; most if not many kohanim today have the
presence of w, probably lack the non-presence of "t", have the presence
of x, have the presence of y, yet lack the presence of both z and u;
unless the kohen holds by RMF before he realizes he has to divorce his
wife and by the Rivash only after. "the wicked rule lekula for themselves
and lechumra for others" Sota 23a (i.e. for a kohen to rule lechumra
for kavod kehuna when it befits him and lekula for kedushat kehuna when
it does not")

This Rabbi said that merely living in a secular college when one
is not very religious constitutes a probablity chazaka of zona,
though certainly dating a non-Jew for an extended period of time
would constitute such a chazaka zona, and I personally know several
kohanim who's mothers were raised reformed and dated non-Jews, yet are
considered kohanim (while a ger or I believe the daughter of two gerim
cannot marry a kohen). Furthermore, many amorim and rishonim darshin
from Sota (actually around that same spot in 23a) that gossip of a
promiscuous woman can create a din chalal and even a mamzer in certain
situations. Additionally, it seems logical that the Maharashdam caused
many chalalim when he permitted kohanim to marry a safek zona based on
the Rivash that all kohanim are safek kohanim. Additionally, I was told
that the mitzvah kavod kehuna is a derabanon according to tosfot and
the Rema and another safek is created if it is unclear if the yisroel
is a greater talmud chacham than the kohen. Also, a probability chazaka
(according what I read) has a higher status than an ordinary status quo
chazaka, and plays a special role in hilchot chazaka.

I hear stories how bat kohanim are given special treatment for shidduchim
and are chosen first for admission into seminary; we are playing with
peoples lives here while lacking sufficient evidence, and in my opinion
it is a real chilul Hashem. One girl named Rachel posted this on her
facebook (a horrible site, never go on it) page; "of course we deserve
respect!! being a bas kohen has opened many doorsfor me, especially in
choshuve sems - and I won't say more, loshon haraahead!"

On a final note, 
א,טו  [טז] רבן גמליאל אומר, עשה לך רב, והסתלק מן הספק; ואל תרבה לעשר אומדות

 about chazaka: 
http://adafaday.blogspot.com/2006/01/chazaka-beats-rov-pesachim-9a.html

- Josh S