פירוש על בבא מציעא 42:14

Granted, the first clause [to] Abbaye - he can find to answer, that he knew from the beginning - as it continues to explain.

The fig tree, too, one knows that [the figs] fell - The explantion: Granted, [in the case of] the fig trees, [taking the figs is] permissible - since it is common that they fall, [the owner] abandons them from the beginning. For he thinks that the finder will take them, for [the latter] did not know that it fell from a tree, but rather thinks that it fell from passers-by. But with olives and carobs, it is forbidden, for they are not prone to falling. Even though if [the owner knew that it fell], he would abandon [it] - as passers-by would take [it], since they would assume that it fell from [other] passers-by. [But] now that they did not know, they would think [the olives or carobs] did not fall - [so] it would be forbidden, as it would be abandonment without awareness. But according to Rava, why would it be forbidden? And if you will say, "If it is the law to assume [the fruit came from] passers-by, and not from the tree adjacent to it, why is it forbidden with olives and carobs" - one can say that according to the law, we certainly do not assume [it was] from passers-by, but from the tree; however, the owners will abandon [the fruit nevertheless], as they think that passers-by who are not upstanding will decide upon a dispensation for the fruit that they find, and assume they were from passers-by. And if you will say, "If so, what is the challenge it presents to Rava; let us say that olives and carobs are forbidden because even after the owners know that they fell, they do not abandon [them], since they know that the finder will not take them; as he will assume that they fell from the tree, as is the truth, since one should not assume [they were] from passers-by - one can say, if they do not abandon [them in the case of] the fig tree, why would [the figs] be permitted? However there are books [of the Talmud] that have the variant, "an olive is different, since its olive tree (zaito) proves about it." For with this, that which we raised as a difficulty is answered. That is to say that since they are below the olive tree, the owners will think that the finder will not take them, to assume [them] from passers-by. But "a fig becomes disgusting with its fall" - the explanation is, it gets dirty and is disgusting to him, so he renders it ownerless. But in most books, we have the variant, "since its appearance (chazuto) proves about it; and even though the olives fall, [the finder] knows that the place of a person is that person's" - the explanation is, olives that fell are similar to olives [still] standing on the tree; and therefore even when the owners know they fell, they will not abandon [them], as they know that the ones that find them will not take them. But "a fig dissolves (nimiset) with its fall" - this is the variant in Arukh - nimiset without an aleph - so they are not similar to those on the tree. And also we can follow the variant [that has] nimaeset (becomes disgusting) - and because it becomes dirty, it is not similar to a fig on the tree.