What practices are included in the prohibition of Geneivas Da'as
(literally - stealing someone's knowledge), the prohibition against
misleading others in business and other interpersonal matters?
A. It is forbidden by the Torah to mislead any fellow human being. This
includes non-Jewish people. This applies to all interpersonal matters,
whether business related or otherwise.
Included in this prohibition is misleading a buyer to think that certain
merchandise is of better quality than it actually is, even if the amount
that he is paying is the correct amount for the item being sold. Also,
saying or doing something that will lead others to think that you have
honored them or done them a favor when this is not so, is included in the
prohibition of Geneivas Da'as. (1)
B. Based on the above, a merchant is obligated to inform a potential
buyer about any defect that exists in an item that the merchant wishes
to sell, if such knowledge may influence the buyer's decision whether or
not to purchase the item. Similarly, a merchant may not claim that an
item was made by a certain manufacturer, or in a certain country, if this
is not true, despite the fact that he will charge the same price in any
C. A salesman may not try to convince a customer to buy something by
telling the customer that the price that he is being offered is one that
others had offered to pay for this item but had been refused. The
salesman may not tell the customer that he (the salesman) is only making
a minimal profit on the sale and this is the lowest amount that he could
In these situations, although the salesman or merchant may have
transgressed the Torah prohibition of Geneivas Da'as, the sale can not be
declared void by the customer when he finds out that the information
provided was misleading. (3)
D. It is forbidden to invite someone for a meal or to an event if the
host knows that his friend will not come, and is only inviting the friend
so that the friend will think that the host wanted him to come, and will
then repay the favor in some manner. On the other hand, if the host knows
that his friend will be insulted not to receive an invitation, even if it
is known that the friend will not come it is permitted to invite him. (4)
E. If someone is hosting a guest and must open a new bottle of expensive
wine for himself, but the guest is under the impression that he did so
in honor of the guest, the host is not obligated to correct his guest's
false impression, since he has not done any action that everyone would
interpret in this manner. However, if there are people that are under the
impression that he has done them a favor or honored them in some manner,
and wish to give him a gift because of this, he may not accept it if it
is really untrue. Similarly, if an organization or school would like to
honor or award someone because they believe that he has attained a
certain level of scholarship that he actually has not, he would not be
permitted to accept this honor or award. (5)
(1) The Gemara in Chullin (94a-b) states that it is forbidden to mislead
people in any way, even a non-Jew. This is also stated as the Halacha in
the Rambam (Hilchos Mechira 18:1), and in the Shulchan Oruch (Choshen
Mishpat 228:6). The Halachos that we have stated here have been taken
directly from the Shulchan Oruch and the SM"A there (9-10).
(2) The SM"A there (7) adds that even when an item has a defect that does
not diminish the value of that item, a potential customer must be
informed about it. Obviously we are referring to a defect that may
influence the customer's decision whether or not to purchase it. A minor
scratch or defect that the average person is not concerned about does not
need to be pointed out, as long as the value of the item is not decreased
(3) It can be inferred from the words of the Shulchan Oruch there (16),
that if people are particular regarding the country or city in which a
particular item was manufactured because certain places have a
reputation for producing quality items, the merchant may not mislead his
customers in any way, neither verbally nor with action, into thinking
that his merchandise is from a particular country when it is not. This is
true even if the items from the country with the better reputation are
the same price as the items from the other countries.
The Ta"z (Choshen Mishpat 332:4) states that although a merchant may have
misled his customers, a customer can not claim that such a sale be
voided, unless he expressly stated before purchasing the item that he is
buying it only because it was manufactured in a particular place, etc.
However, the merchant has transgressed the Torah prohibitions of Geneivas
Da'as, besides the prohibitions involved in saying falsehoods.
(4) This is stated in the Shulchan Oruch, Choshen Mishpat (228:6), and
the SM"A there (8).
(5) The Gemara and the Shulchan Oruch there state that when people are
not misled, but jump to conclusions based on their own mistaken
impression, you are not obligated to correct the impression that they
have. However, we find in the Yerushalmi (Makos Perek 2 at the end of
Halacha 6) that if a person knows only one Masechta (tractate) of the
Gemara, yet people want to honor him because they are under the
impression that he knows two Masechtos, he must tell them the truth,
even though he did nothing to mislead them! How can we reconcile the
position of the Yerushalmi, and our Gemara in Chullin? It does not seem
reasonable that we should make a distinction between Geneivas Da'as when
it comes to knowledge in Torah and other matters!!
It appears that this can be answered in the following two ways:
A - The Yerushami is talking about a situation where the Talmid Chochom
is participating in a ceremony honoring him for his "achievement". His
participation creates the impression that what they are assuming is true.
Consequently, he is misleading people with his actions, and it is
B - It is possible that the Yerushalmi is not concerned about the
Geneivas Daas of those that are honoring him, since they are misleading
themselves. The problem is that the recipient of the honor is receiving
something that he does not deserve, which is forbidden when it is being
given mistakenly. In other words, if he would be given a discount in a
certain store, for example, based on the assumption that he is more of a
scholar than he actually is, he would clearly be forbidden to take it.
To do so would be theft. So too here, he should not take this honor
being bestowed on him when he is truly not deserving of it.
According to the first reason that we've just stated, the problem is that
he is misleading those who are giving him the honor. According to the
second reason, the problem is that he is accepting something of which he
is not deserving, even though there is no Geneivas Daas, since he has
done nothing to mislead the others. However, if he receives nothing
beneficial because of the erroneous assumption of others, they merely
have gratitude for what they think that he has done for them, and does no
action at all to give them the impression that they are correct,
according to both reasons he would have no obligation to inform them that
they are mistaken. It is in this situation that the Gemara and Shulchan
Oruch state that you have no obligation to correct your friend's mistaken
impression so that they do not have gratitude for something that you
actually haven't done for them.
This week's class is based on a column by Rabbi Tzvi Shpitz, who is an Av
Bais Din and Rosh Kollel in the Ramot neighborhood of Jerusalem. His
Column originally appears in Hebrew in Toda'ah, a weekly publication in
Jerusalem. It has been translated and reprinted here with his permission
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presence of all parties involved!