QUESTION: The Mishnah (52b) states that one who accidentally defiles his friend's Tahor fruits, mixes his friend's Chulin with Terumah so that a non-Kohen may not eat it, or makes his friend's wine into Yayin Nesech, is exempt from liability for the damages. If he did so willfully, he is obligated to pay for the damages.
The Gemara cites a dispute between Chizkiyah and Rebbi Yochanan with regard to the reasoning of the Mishnah. Chizkiyah maintains that according to Torah law, one is obligated to pay for "Hezek she'Eino Nikar" -- "damage that is not recognizable," whether he caused the damage accidentally or willfully. The only reason why the Mishnah exempts him from liability when he causes such damage accidentally is to encourage him to reveal the item's true status to the owner without having to worry that he will have to pay. Rebbi Yochanan maintains that mid'Oraisa one is never obligated to pay for damage that is not recognizable. However, the Rabanan decreed that one who willfully causes such damage should pay in order to deter a person from damaging the property of another in this way.
Rebbi Elazar questions Chizkiyah's opinion from a Beraisa. The Beraisa states that if a person performs work with Mei Chatas (the water used in the Taharah process with the ashes of the Parah Adumah) or with the Parah Adumah itself, he is exempt from liability in the laws of Beis Din, but in the laws of Shamayim he is held accountable. (The Torah (Bamidbar 19:2, 9) states that doing work with the Mei Chatas or Parah Adumah renders them unfit for use.) Rebbi Elazar asks that according to Chizkiyah who says that one is liable for such damage according to Torah law, why is he exempt from liability in the laws of Beis Din when he renders the Mei Chatas or Parah Adumah unfit for use? (The MAHARSHA addresses why the Gemara does not ask the same question from the Beraisa on the opinion of Rebbi Yochanan.)
Rebbi Elazar answers his own question by asserting that the Beraisa refers to a case in which a person placed the young Parah Adumah calf into its pen so that it should suckle from its mother and thresh the produce together with the other animals. Since the only reason why the calf becomes unfit is that the person's intent was that it should also thresh, it is impossible to make him pay because of his thought alone, for his thought certainly is only a "Gerama" -- "indirect damage." Similarly, the Gemara concludes that the Mei Chatas becomes invalid because of "Hesech ha'Da'as" (he neglected to keep in his mind at all times that he was guarding the water in order that it be fit to be used as Mei Chatas; see Rashi DH Masnisin). Since the damage depends on his thoughts (or lack thereof), it is deemed indirect damage for which he is not held accountable in Beis Din.
The Gemara here apparently contradicts the Gemara in Bava Kama (98a). The Gemara there states that one who picks up his friend's coin and throws it into the sea must pay for the loss of the coin. The Gemara there understands that when one picks up an object with intent to damage it, he acquires the status of a thief and becomes obligated to return the stolen object. Accordingly, the one who throws the coin into the sea is now obligated to return the object, even though the damage occurred only through "Gerama" (the coin is not actually damaged but is merely inaccessible). In the case of the Gemara here, the person does an action which causes damage -- he prods the calf into the pen or picks up the water and puts it on a scale. According to the Gemara in Bava Kama, he should be obligated to pay in this case since his action with intent to damage should give him the status of a thief who is obligated to return the object. How are these two Gemaras to be reconciled?
(a) The CHAZON ISH (Bava Kama 2:13) suggests that the Beraisa here refers to a case in which the person had a "Hesech ha'Da'as" at the moment he lifted up the Mei Chatas. Since the water became invalid at the same time that he picked it up, it is considered as though he picked up Mei Chatas that was already unfit. The damage is deemed to have been done before he picked up the Mei Chatas, and thus it is like he stole water unfit to be Mei Chatas. Accordingly, he may return water that is unfit to be Mei Chatas. Similarly, in the case of the Parah Adumah, the calf is considered to have threshed before he had in mind that it should do so. (See the Chazon Ish who offers other answers at length.)
(b) The KEHILOS YAKOV (Bava Kama 41) answers based on the words of TOSFOS (53b, DH Gazlan), who discusses the circumstances under which a thief is entitled to claim, "Harei Shelcha Lefanecha" (he returns the stolen object to the owner and claims that it is sufficient compensation), according to the opinion of Chizkiyah who says that one is not liable to pay for unrecognizable damage. When a thief steals fruit and some of it rots in his possession, he may return the fruit in its present state to the owner and say, "Harei Shelcha Lefanecha." This is because the fruit is still extant and has undergone no "Shinuy" (significant change). In contrast, in a case in which a thief returns a stolen coin that has gone out of circulation, or he returns stolen Chametz after Pesach, the stolen object has become valueless. In such a case the thief may not claim, "Harei Shelcha Lefanecha."
Accordingly, the case of the Gemara in Bava Kama is unrelated to the case of the Gemara here. The Parah Adumah and Mei Chatas have value aside from their usefulness for the Taharah process. The Parah Adumah is a calf which has added value when it is eligible for use for the Taharah process, and the Mei Chatas is a jug of water which has added value when it is eligible for use for the Taharah process. Rendering them unfit for use for the Taharah process is not a significant enough change because it does not take away their inherent worth (as a calf or as water). The Kehilos Yakov suggests that this is similar to the case in which a thief steals fruit and only some of the fruit rots, in which the claim of "Harei Shelcha Lefanecha" is still applicable. Accordingly, in the cases of the Gemara here, one still may claim "Harei Shelcha Lefanecha" and thereby fulfill his obligation to return the object. In the case in Bava Kama, the thief cannot claim "Harei Shelcha Lefanecha" simply because he does not have the coin which he stole. (See also AYELES HA'SHACHAR to Bava Kama 98a.) (D. BLOOM)