Suspect Payments
On the one hand, the case of the suspect banknote seems to fit this halachic template. The debtor was previously obligated towards the creditor, and a doubt has now arisen over whether or not payment has been legitimately made: if one of the banknotes was counterfeit, the debtor has not paid back his debt. Because the creditor’s claim is certain, and the debtor’s defence is uncertain, the halachah would seem to side in favour of the creditor.
Yet, there is another way of analysing the case of (suspected) counterfeit payment. Before the alleged counterfeit was discovered, both parties had considered the debt repaid. Because the assumption was that the debt no longer exists, perhaps there are no longer grounds to view the debt as a previously existing debt—in other words, perhaps the original repayment of the debt annuls the chezkas chiyuv, thereby rendering the debtor exempt from paying?
Addressing precisely such a case, Shach cites from the weighty authority of Rashdam, ((Rashdam 3:80.)) who rules that since doubt was cast on the payment of the loan the borrower is obligated to pay. ((Shach, CM 232:16.)) Concluding, Shach states that this ruling is simple: a chezkas chiyuv exists in favour of the creditor, and the creditor’s certain claim outweighs the borrower’s uncertainly.
Taz, however, states that the clear ruling is the contrary. Because the borrower has already paid, and the current status quo is that he is not longer obligated in payment, the creditor’s claim is not considered as continuing the original obligation. The concept of chezkas chiyuv is not applied, and we return to the basic principle of bari veshema,lav bori adif: The strength of a certain claim (against an uncertain claim) is insufficient to extract payment. ((Taz, CM 75 (end).))
Counterfeits and Miscounts
An annotation to Be’er Heitev cites a list of authorities who disagree with the ruling of Shach ((See Be’er Heitev, CM 232:24)). Moreover, we are referred to a statement of Shach himself, ((CM 126:69, citing from Rashba, Gittin 14a.)) which rules that if a borrower paid back his debt, only for the creditor to claim that there was a miscount and not enough money was given, the debtor is exempt from further payment, in spite of his uncertainty as to the creditor’s claim.
This appears to be in direct contradiction with the above ruling of Shach: The question regards the validity of the debtor’s repayment, yet his uncertain claim is sufficient to exempt the debtor from further payment.
Without mentioning the contradiction, Ketzos Hachoshen resolves the issue by making a distinction between a miscount and counterfeit money. Because Beis Din always assumes that money is properly counted, ((See Shulchan Aruch, CM 126:13.)) it follows that a claim of miscounting cannot receive the backing of a chezkas chiyuv (an assumption of obligation): the basic assumption is that the money was correctly counted, and the debt repaid in full.
On the other hand, there is no basic assumption that coins are not counterfeit. The claim of counterfeit money is therefore able to cast a doubt on the original payment, relying on the chezkas chiyuv of original debt. The certain claim of the creditor thus defeats the uncertain claim of the debtor, who must make the payment.
Conclusion
It emerges, at any rate, that the case of alleged counterfeit notes involves a major dispute amongst authorities. Because Taz, ((Loc. Cit.)) Tumim, ((CM 75:22.)) and several other poskim disagree with the ruling of Shach, the debtor, who is in holding of his money, would not have to make a second payment to the creditor.
However, this is true only insofar as the debtor does not trust the creditor in his claim of finding counterfeit notes. If the debtor does not suspect the creditor of falsehood, he must make a second payment, to avoid the proscription of gezel. The wording of our question implies that the debtor has no reason to distrust the creditor, and it is therefore correct to pay again.
We should also point out that even when he is doubtful of the truth, the Gemara ((Bava Kama 118a.)) and Shulchan Aruch ((Choshen Mishpat 75:9)) teach that one who wishes to “fulfil the obligation of Heaven” should pay in every case of an uncertainty in the face of a certain claim (bari veshema). Although Beis Din does not enforce the payment, one who pays out of doubt is doing a worthy act, and not merely giving a gift.
Because making the payment is a halachic requirement of sorts (though not obligatory, it is worthy), it follows that there is no concern of ribis (proscribed payments of interest) in paying a second time.
In conclusion, the soundest advice, from both a practical and halachic perspective, is to ensure that there are no counterfeit notes at the time of payment!
