Aharon and Yosef were sitting in the public library, browsing some of the books on display and doing research for a project.

As Aharon picked up one book, he noticed that it was a Pesach machzor. He showed it to Yosef and said, “There’s no stamp on this machzor. Could it belong to the library?”

Yosef took the machzor and looked it over. “The library does not own any machzorim like this,” he said definitively. “Someone must have left it here on Chol Hamoed Pesach.”

Yosef flipped through the pages, looking for some identification. “It looks like it was left for a while and the owner probably despaired,” he said. “Since there are no identifying marks, the item is hefker (ownerless) and can be taken; I’m taking it for myself.”

“What do you mean, you’re taking it for yourself?” said Aharon. “I picked it up first! If it has no identification and is hefker — then it’s mine!”

“Why should it be yours?” said Yosef. “You gave it to me.”

“I never gave it to you to keep; I just handed it to you to see,” replied Aharon. “I thought you might know about it! But if it’s ownerless, I found it. I picked it up first!”

“You didn’t find it at all,” said Yosef. “You just picked it up to see what it was.”

“So what? I picked up the machzor first,” replied Aharon. “That’s enough to make it mine, not yours.”

“I don’t think so,” said Yosef. “You need intention to acquire it; you had no such intention.”

“Let’s ask Rabbi Dayan,” Aharon suggested.

“Agreed,” said Yosef.

The two came to Rabbi Dayan. “I picked up a machzor thinking that it was the library’s and passed it to Yosef,” said Aharon. “It turns out that the machzor has no identification, so Yosef wants to take it. Whom does the machzor belong to?”

“There are seemingly contradictory sources,” answered Rabbi Dayan. “On the one hand, the Gemara (Yevamos 52b) states that one who digs in an ownerless field (which belonged to a convert who died without heirs) but mistakenly thought that the field was his own, does not acquire it. Although digging is an appropriate means of acquiring an ownerless field, the person thought the field was his own, so he had no intention to acquire it” (C.M. 275:24-25).

“On the other hand,” continued Rabbi Dayan, “the Gemara (B.M. 10a-b) addresses the case of a person who fell on a metziah to acquire it. Falling on a metziah is not a valid means of acquisition. However, the Sages instituted that whoever approaches a metziah within 4 amos in a semi-public area acquires it through his proximity. The Rema rules according to the opinion that a person who fell on an item acquires it through his proximity, despite the fact that he indicated his intent not to acquire it through proximity, but through falling” (Rema, C.M. 268:1).

“How do we resolve these contradictory sources?” asked Yosef.

“Mishneh Lamelech explains that in the second case, where the person fell on the metziah, he intended to acquire it at that time, in one manner or another,” replied Rabbi Dayan. “The particular manner of acquisition — proximity or falling — is less critical. However, in the first case, where the person dug in ownerless land, he had no intention at all to acquire the field” (Pischei Teshuvah, C.M. 198:9).

“What about the opinion of the Shulchan Aruch?” asked Aharon.

“The Shulchan Aruch is more stringent,” replied Rabbi Dayan. “He rules in a few places that intention for the particular means of acquisition is also critical: the person who fell on the metziah does not acquire it through proximity” (C.M. 198:12; 200:8; 268:1).

“Thus,” concluded Rabbi Dayan, “since Aharon had no intention whatsoever of acquiring the machzor when he picked it up, he did not acquire it even according to the Rema, and it belongs to Yosef. I would recommend posting a notice, though, to see whether someone claims the machzor, and return it, beyond the letter of the law” (see C.M. 259:5; Pischei Choshen, Kinyanim 1:13; Dvar Chok Umishpat, pp. 20-22).