We live in a city with a sizable religious population but also a significant percentage of traditional but non-religious families. The Rabbonim of the community organized a campaign to encourage stores to have their workers dress modestly and to play proper music, by giving free advertisements in the local religious publications to stores who conform. I purchased an electric appliance in a store that conforms to the Rabbinic guidelines. When I checked out I told the proprietor that I bought by him because he conforms to the Rabbinic guidelines. However, while it is true that I prefer to buy in such a store and if two stores charge the same price I would buy from the one that conforms, nevertheless, in this particular case the true reason I bought from this store is because the price was cheaper than the price at competing stores. Did I violate the prohibitions of geneivas da’as or sheker-lying?
In order to answer your question it is important to understand the nature of these prohibitions.
Many Rishonim (e. g. Yeraim 124, Semag (lavin 155), Ritvo (Chulin 94A)) maintain that the prohibition of geneivas da’as is from the Torah and the source is the pasuk (Vayikro 19, 11) that prohibits monetary theft. These Rishonim cite the Tosefta (BK 7, 8) that writes that there are seven forms of theft and the worst of all is geneivas da’as. Thus part of the nature of the prohibition is that it is a kind of theft.
These Rishonim cite as proof that the prohibition is from the Torah, a statement of the Gemoro (Sotah 9B) that the reason Avshalom was stabbed to death three times by Yoab is because he was guilty of geneivas da’as on three groups of people. They reason that if one who violates this prohibition is punished by death, the prohibition must be Torah-based.
They cite as further evidence that geneivas da’as is a Biblical prohibition, the Gemoro (Chulin 94A) that states that even if the victim of the geneivas da’as is a non-Jew the prohibition applies, even though many maintain that monetary theft from a non-Jew is only a Rabbinic prohibition. Thus, we see that the reason geneivas da’as is a form of theft is not because the result is that the victim suffers a monetary loss because if so it could not be worse than actually directly stealing someone’s possessions. Yet in the case of a non-Jew geneivas da’as is prohibited, while stealing his money is not a Biblical prohibition.
Besides theft, geneivas da’as has an element of sheker-falsehood. This point is stressed by Rabbeinu Yona (Sha’arei Teshuva 3, 184) who writes that the reason the prohibition applies even where the victim is non-Jewish even though actual theft may not be prohibited (from the standpoint of the Torah) is because of the element of falsehood.
The Zohar (Yisro) also derives the prohibition of geneivas da’as from the previously cited pasuk and derives an important ruling based on the musical reading notes on the words of the pasuk from which the prohibition is derived. Under the word “you shall not” appears a note that separates the word from the word “steal” which leaves that word to stand on its own so it makes the pasuk sound like it is saying “you shall steal.” The Zohar resolves this strange contradiction to mean that there are situations when one should do an act that constitutes geneivas da’as.
Since sometimes one may employ geneivas da’as and sometimes one may not and the Gemoro does not offer any direct guidance to determine when the prohibition applies and where it does not apply, we must study the cases discussed in order to determine when geneivas da’as is prohibited and when permitted.
Besides geneivas da’as to obtain another person’s property we find in the Gemara that the prohibition applies where the purpose is, like by Avshalom, in order to gain respect and power.
Another instance where geneivas da’as is explicitly prohibited is where the goal is friendship based on false pretenses. An example of this is one who implies that he is prepared to suffer a significant monetary loss in order to honor someone, when he is not really prepared to suffer any loss. The example cited by the Gemoro (Chulin 94B) is one who opened a new barrel of wine to serve a guest where the host already had customers for the remaining wine in the barrel. The guest is given the impression that the host is willing to risk a significant monetary loss in order to honor him with a drink of wine (since once a barrel is opened the wine has a short lifespan), when in fact he had no risk of any monetary loss.
The example which the Zohar gives where one may employ geneivas da’as is where the person wants to acquire Torah knowledge.
Another famous example where geneivas da’as was employed, was in Aharon Hacohen’s efforts to make peace between two bickering Jews. In Avos deRabbi Nosson (12, 3) it says that Aharon would tell each party that the other felt terrible and had remorse for what he did, when in fact this was not the truth.
Thus, we have established that even though geneivas da’as is prohibited, nevertheless, there are situations where the Torah recommends that it be employed. This teaches us that the prohibition of geneivas da’as is different from general prohibitions which apply categorically, to all situations. Rather, the determination whether geneivas da’as is permitted depends on the goal that one wishes to achieve by employing geneivas da’as.
Thus, your question is whether your intended use of geneivas da’as to cause the proprietor of the store to continue to conform with the Rabbinic guidelines justifies using geneivas da’as in order to achieve this goal.
Thus far we have seen that one may employ geneivas da’as in order to acquire Torah knowledge and in order to make peace. Making peace is not so significant since we find other aveiros which one may ignore in order to achieve peace. For example the Gemoro notes that Hashem even allowed His name to be erased in order to bring peace between a husband and his wife.
We also find in the Gemoro (Eiruvin 51A) that one may employ geneivas da’as in order to impart correct Torah knowledge to others. The situation that the Gemoro discusses is where one amoro, in order to ensure that another amoro would rely on a leniency, cited a reliable source for the leniency even though he did not know that the reliable source had in fact ruled this way. However, since the amoro was certain that this was the correct ruling he was allowed to cite the reliable source for the ruling.
We find in the Gemoro many sources that one may use geneivas da’as in order to cause correct behavior. One case (Yevamos 106A) is where a brother-in-law wished to perform yibum and wed his deceased brother’s wife. Normally, this is a big mitzvah, but in this particular case the proper action was to perform chalitza and release his sister-in-law. The Gemoro ruled that in case the brother-in-law refuses to listen to the Rabbis and perform chalitza, the rabbis may tell him that if he will perform chalitza he will receive a large sum of money. However after he performs the chalitza they can inform him that he is not entitled to the money because they never intended to give him the money. Thus we see that deceit is allowed if the goal is to cause a person to act in a proper manner.
Similarly in your situation, since the desire of the rabbonim and you is that the store and its employees should act in the proper manner, there is nothing amiss in using geneivas da’as in order to achieve that goal.
We note that your action was an act of geneivas da’as and the only reason it was proper is because the ends justify the means. This is so because even attributing one’s action to a secondary – but true – reason is considered falsehood. The source for this is the Maharsho who asks on the Gemoro (Yevamos 65B) that derives from Hashem’s telling Shmuel to tell everyone that he came to Bethlehem to sacrifice a korbon (Shmuel I chapter 16), that one may speak falsely for the sake of peace. He asks that Shmuel did bring a korbon when he came to Bethlehem so how do we see that one may speak falsely? He answers that since this was not the principal reason for his visit his statement was false. (Hashem’s entire suggestion to bring a korbon was geneivas da’as to hide the real reason for his visit.)
In conclusion: You acted properly when you told the proprietor that you bought by him because he listened to the rabbonim even though this was not the full truth, since the purpose of your deceit was to encourage proper behavior.