Kiddushin 8a: The Principle of Li'Didi Shaveh Li – Market Value vs. Benefit Received

This shiur analyzes the Rambam (רמב"ם)'s ruling in Hilchos Bikurim regarding the principle of li'didi shaveh li—the halachic mechanism by which a kohen can accept an object worth less than five shekalim as fulfilling the requirement of pidyon haben when he receives it "as five shekalim." The Rambam states that if the father gives a vessel not worth five shekalim, but the kohen accepts it as five, the son is redeemed. Several preliminary observations challenge conventional understandings: First, the Rambam applies this principle even to objects worth less than a shaveh peruta, suggesting li'didi shaveh li works even below the minimal threshold of monetary value—a position not shared by the Ran, who limits it to objects close to peruta value. Second, the Gemara (גמרא)'s limitation that only Rav Kahana (a gavra raba, great person) can say li'didi shaveh li appears to contradict the Braisa which states the halacha (הלכה) without qualification. The shiur examines four approaches to reconciling the Rambam with the Gemara's limitation. The Beis Yosef suggests that as long as there exists one person in the world for whom the object is worth five shekalim, everyone can use li'didi shaveh li. This approach is challenged both conceptually (why should one person's valuation create universal value?) and textually (the Rambam never mentions this condition). The Bach proposes that when the father explicitly states the object is worth five, the kohen's acceptance suffices; only when the father is silent must the object actually be worth five to the kohen. This reading is rejected as contradicting the plain language of both the Gemara and Rambam. The Taz argues there are two separate halachos: when the kohen explicitly accepts it "as five" it works even if worthless to him, but when he merely receives benefit worth five without explicit acceptance, it must actually be worth that much. This too is found conceptually untenable—how can mere words create value when no actual benefit exists?