Aharon and Yosef were cleaning up the shul three days after Pesach. They were sorting all the siddurim and chumashim that had been returned helter-skelter to the bookcases.
As Aharon picked up one Chumash, he noticed it looked unusual. He showed it to Yosef and said, “There’s no shul stamp on this Chumash. Where should we put it?”
Yosef took the Chumash and looked it over. “The shul does not own any chumashim like this,” he said definitively. “Someone must have left it here over Pesach.”
He flipped through the pages, looking for some identification. “Absolutely no marks; it’s brand new,” Yosef 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 keeping 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,” replied Aharon. “I thought it was owned by the shul. But if it’s ownerless – I found it and I picked it up first.”
“You didn’t find it at all,” said Yosef. “You just picked it up to put it away in its proper place.”
“Bottom line, I picked up the Chumash first, though,” replied Aharon. “That’s enough to make it mine, not yours.”
“I don’t think so,” said Yosef. “You need intention to acquire it.”
“Let’s ask Rabbi Dayan,” Aharon suggested.
The two came before Rabbi Dayan. “I picked up a Chumash thinking it was the shul’s and passed it to Yosef,” said Aharon. “It turns out the Chumash has no identification, so Yosef wants to take it. Whom does the Chumash belong to?”
The Chumash belongs to Yosef,” ruled Rabbi Dayan. “Although Aharon picked it up first, he had no intention of acquiring the Chumash when he did so. Therefore, the Chumash remains hefker and Yosef acquired it.”
“Do you really need intention in order to acquire something?” asked Aharon. “I remember a discussion in the Gemara about falling on a lost item…”
“There are some seemingly contradictory sources,” answered Rabbi Dayan. “On the one hand, the Gemara [Yevamos 52b] states clearly that if one digs in an ownerless field [which belonged to a convert who died without heirs] but mistakenly thought the field was his own, he does not acquire it. Although digging is an appropriate means of acquiring an ownerless field, since the person thought the field was his own, 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] has two opinions regarding a person who fell on a metziah to acquire it. The act of falling is not a valid means of acquisition, but the Sages instituted that whoever first approaches a metziah within 4 cubits in a semi-public area, acquires it through his proximity. The Rama rules that the person acquires who fell on the item acquires it through his proximity, despite the fact that he mistakenly intended to acquire it through falling, not through proximity.” (Rama 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, at least he intended to acquire it at that time, in one manner or another,” replied Rabbi Dayan. “The particular manner of acquisition is less relevant. 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)