Daf Hashavua Pesachim
54b
Bein
Hashmoshes , we consider night, Lechumra. (Erev Shabbos,Tisha B’av etc.)
Why don’t we
say every Bein Hashemoshos has a Chazaka that it is day ?
Whenever we don’t know
(safek) when a change happened, Chazaka tells us to assume,it happened at the
latest possible time.
Why don’t we consider
Bein Hashmoshes Vadai (sure) day, the original status ?
Answer:
The ( שמעתא ג' פרק ט'-י' ) *שב שמעתתאsays חזקה העשויה להשתנות אינה
חזקה a
Chazaka that will
definitely
change is not considred a Chazaka.
A cow that was found to
be Treifoh, Chazaka makes us assume that it happened the
latest possible time.
All the milk from before this period is considered kosher .We have a Chazaka
because not every animal becomes Treifoh. However Every
Bein Hashmoshes will eventually
become night, therefore
we have no Chazaka.
*Quotes the Maharit
