כפילא ארבע וחומשא זוזא – The double is four and the fifth is a זוז
Summary:
The meaning of חומשו עולה לו בכפילו is that the payment of the כפל (if it equals the חומש [according to רש"י]) substitutes the payment of the חומש (and not the reverse). According to the ריב"א the כפל payment substitutes the חומש if it is equal to or greater than the חומש.
אלמא קרן כעין שגנב –It is evident that he pays for the principal as it was worth when it was stolen
Summary:
We cannot differentiate between קרן and כפל (concerning כעין שגנב or כשעת העמדה בדין) unless there is a פסוק that indicates so (as רב taught). Even when a proof is refuted, the אוקימתא should not be שלא כהלכתא if at all possible. The refutation is more complete if the new אוקימתא is precisely the one that was initially rejected in order to make the proof.
Summary:
רבא maintains that even if שינוי is קונה the changed אתנן cannot be brought as a קרבן since it is אמאיס לגבוה; while רב ששת maintains that if שינוי קונה, then the changed item is considered a different item and would not be considered מאיס לגבוה.
הן ולא שינוייהם – ‘They’; but not in their changed state
Summary:
All agree (including רב חסדא ור' יוחנן) that שינוי שאינו חוזר לברייתא is קונה. However רבה adds that even a שינוי חוזר is also קונה because there are two פסוקים. Both משניות which רבה cites as proof are discussing a שינוי החוזר.