Editing Mesechtas Bava Metzia (section)

== Explanations of the Tzemach Tzedek ==
'''Yeush''' (giving up hope) is a halachic state in which a person has given up hope of recovering his property that is not in his possession, thereby relinquishing his ownership of the object. "Yeush shelo midaat" (unconscious abandonment) is a situation where it is known that if the person had known that the object was lost, he would certainly have given up hope, but he has not yet heard about it and therefore has not consciously given up hope.

There is a dispute between Abaye and Rava regarding the status of such an object. According to Abaye, it is not considered as if the person has given up hope, even though immediately upon hearing about it he would give up hope - this does not retroactively reveal that this was his true intention previously. But according to Rava, since it is clearly known that this would have been his intention (for he immediately gave up hope when he heard about it), and it is clear that in the previous situation he would have given up hope as well, it is considered as if he had actually given up hope earlier.

Although there is a general dispute in the Talmud regarding whether "ein breira" (there is no retroactive designation) or "yesh breira" (there is retroactive designation), which relates to the general question of whether a later action can clarify a previous situation, such as setting aside terumah (priestly gifts) with the intention that what will be set aside in the future is what is designated as terumah now - despite this, the question of "yeush shelo midaat" is a separate issue and does not depend on that dispute.

The reason for this is that with terumah, there is no reason to say that the terumah set aside later is the same terumah that would have been set aside earlier, and therefore the separation of terumah is a new designation and cannot clarify the past - according to the view that "ein breira." The situation with "yeush shelo midaat" is different, because here it is clear that even earlier, if he had heard about it, he certainly would have given up hope.