How can a person sell the offspring of his birds or bees if the offspring
have not yet been born? Since they have not yet been born, they are
considered a "Davar she'Lo Ba l'Olam" -- an object that is not yet in the
seller's domain at the time of the sale, as the Gemara says earlier (79b)!
Although Rebbi Meir allows the sale of a Davar she'Lo Ba l'Olam, according
to the Rabanan (whose opinion is the Halachah), a person does not have the
right to sell what is not yet in his possession. Even when the object does
come into existence, the seller is not bound by agreements he made before
the objects came into existence. How, then, can a person sell the produce of
his hive or dovecote which has not yet come into existence, according to the
Rabanan or Rebbi Meir?
(a) The NIMUKEI YOSEF and MEIRI point out that although the seller may back
out from the sale of a Davar she'Lo Ba l'Olam at any time, if he does not
back out from the sale the buyer is entitled to keep what he purchased.
Accordingly, the Mishnah might be discussing a case in which the seller does
not back out from the sale, and it is teaching merely which items were
included in the sale that he agreed to make.
(b) The RAMBAM (Hilchos Mechirah 23:9, also cited by the Nimukei Yosef)
answers that the case of our Mishnah is *not* considered to be a case of a
Davar she'Lo Ba l'Olam. His reasoning is as follows. When a person sells a
palm tree for the rights to its future fruits (but not for the wood of the
tree itself), the sale is not considered to involve a Davar she'Lo Ba
l'Olam. The reason is because the palm tree itself is already in existence,
and it is the palm that is being sold with regard to the rights to the
fruits that it will produce, not the fruits themselves. That is, the buyer
is purchasing the palm tree for a specific use: to have rights to the fruits
that the tree grows (see Bava Basra 132b, 147b).
The Rambam asserts that the same principle applies to the sale of a hive or
a dovecote for its produce. The item being sold is a hive or a dovecote, not
the offspring of the bees or birds that are not yet born. However, the sale
of the hive and dovecote is only for a particular use: to keep the bees and
doves that are born inside of them in the future. Since the sale takes
effect on something that already exists in the world, the sale is valid. The
seller is not selling a Davar she'Lo Ba l'Olam. The Rambam compares this to
a person who rents a stretch of area of a river in order to hunt the fish in
it; even though the fish are not yet there at the time of the sale, the sale
is valid, since the *river* is being sold (for the purpose of fishing in it)
and not the *fish* that will later come to the river.
There is a difficulty with the Rambam's answer, though.
The Gemara in Gitin (42b) questions whether a person can sell his slave
solely in order that the buyer will receive the rights to collect the
thirty-Shekel penalty if the slave is gored by an ox. The Gemara explains
that perhaps the Rabanan who argue with Rebbi Meir allow a person to sell a
slave in order to collect the penalty payment, even though the penalty
obligation does not yet exist, since the slave and ox already exist (and
hence the payment is not completely non-existent; it is comparable to one
who sells a palm tree for its future fruit). The Rishonim explain that the
other side of the question is that selling a slave for the right to collect
the penalty is *not* comparable to selling a palm for its fruit, since the
fruit comes directly from the palm and is a physical derivation of the tree,
while the penalty derives from the slave only in an indirect manner (TOSFOS
DH Eved, RASHBA). The Gemara does not decide the Halachah in the case of the
slave, but leaves the question unanswered. In Bava Metzia (33b) the Gemara
seems to prefer the possibility that such a sale is not valid (see Tosfos
The same reasoning should apply to one who sells a hive or dovecote for its
produce. Since their produce does not physically derive from them, it should
be considered a Davar she'Lo Ba l'Olam, like the penalty given for the
goring of a slave!
The answer might be that, according to the Rambam, one may sell future
products even if they do not physically derive from a pre-existing object as
long as the products come about through *natural processes* (such as being
born in a dovecote). The Gemara's question in Gitin involves a product
(penalty) which is derived Halachically and not through any physical
process. Proof to this distinction can be found in Kesuvos (59b), where the
Gemara suggests that a person can even sell or be Makdish his hands or his
slave's hands for what they produce. In such a case, the handiwork that is
produced certainly is not a product that grows physically *from* the hands,
but rather it is a product produced *by* the hands, and yet it can be sold
as a product of the hand since it is produced through natural, physical
However, the RASHBA (in Kesuvos and Gitin there) infers from another Gemara
(Bava Metzia 16a) that if a person sells a fishing net for its products (the
fish that it will catch), it is considered to be a Davar she'Lo Ba l'Olam
and the sale is not valid, since the fish do not derive *from* the net, but
are only caught *by* the net. The KETZOS HA'CHOSHEN (209:4) points out that
the Rashba seems to be arguing with the Rambam, who writes (as we mentioned
above) that a person *can* sell a river for fishing rights or a hive for the
bees that will settle in it.
It is possible, though, to reconcile the words of the Rashba with the
teaching of the Rambam in a number of ways.
1. The Rashba there asks why a person can be Makdish his slave's hands for
what they produce if he cannot sell a fishing net for what it will catch. He
answers that the fishing net does not *actively* produce, or even catch,
fish. It simply stays in place, waiting for a fish to swim by and get caught
in its strings. The rights to the future fish are therefore not included in
the sale of the net. The same is true of the penalty that comes from a gored
slave; it does not result actively from the slave. Hands, in contrast, do
actively produce their handiwork, and therefore the future handiwork can be
transferred through the sale of the hands.
(c) The RA'AVAD (Hilchos Mechirah, loc. cit.) agrees to the principle of the
Rambam that it is possible to sell a bee-hive for its fruits just like one
can sell a tree for its fruits. However, he adds that the case of our
Mishnah must be a case in which the seller *specifies in his sale* that he
is selling "a hive for its products." If he simply says, "I am selling you
the products of my hive," the sale is not valid because it is a Davar she'Lo
Ba l'Olam. This is also the opinion of the YAD RAMAH and MEIRI here.
Perhaps the products of a hive and dovecote are comparable to the handiwork
of hands, since they are indeed produced by the hive and dovecote in a
sense. The hive and dovecote provide a comfortable environment for the bees
and birds, attracting them to come and make their home there. The same
applies to a river that is sold for its fish; fish are attracted to a river
or to a certain part of a river. Therefore, they can be transferred in a
sale as "products" of the river. A fishing net, though, does not "produce"
fish in this manner. (Even if it is baited, it is the bait that is
attracting the fish and not the net.) The fish simply enter it on their own
and become caught in it. (M. Kornfeld)
2. The KETZOS HA'CHOSHEN (209:4) asks that it should be possible to sell a
fishing net for its fish even though the fish are not produced by the net.
The fishing net, as a utensil owned by the fisherman, should be able to
acquire the fish that become caught in it for the fisherman through Kinyan
Chatzer. Hence, it should be possible to sell the rights to what the net
acquires through Chatzer!
It is true that perhaps one cannot own an object *solely* with regard to the
rights to what it is Koneh through Chatzer. Kinyan Chatzer is a *byproduct*
of the ownership of an object or piece of land. The rights of Kinyan Chatzer
cannot constitute the entire ownership itself. However, what a net acquires
through Chatzer is certainly directly produced by the net (through the
Kinyan that it makes). Thus the Rashba should have compared it to the
produce of one's hands!
HAGA'ON RAV YISRAEL ZEV GUSTMAN zt'l (in Kuntresei Shi'urim, Bava Metzia
13:9) answers that the net cannot acquire fish through Kinyan Chatzer
because a fish does not "land" or "come to rest" on a net on its own.
Rather, the fisherman actively catches fish in his net by moving it around
in the water until he has the fish tangled in the net. The net is not acting
like a Chatzer and cannot be Koneh through Kinyan Chatzer. If, on the other
hand, the net is already in place and catches fish passively, it will indeed
by Koneh with Chatzer.
However, the Rashba (at the end of Kesuvos, and as printed in recent
editions on Kesuvos 59b) seems to contradict this postulate, since he rules
that an entirely *passive* net, one that is already in place, cannot be sold
for the fish that it catches.
Perhaps a fishing net is considered a Chatzer she'Eino Mishtameres, an
unguarded Chatzer (which is not Koneh through Kinyan Chatzer), since anyone
can come and take fish from it. Consequently, it cannot acquire through
Kinyan Chatzer (as the Gemara says in Bava Metzia 11b). A hive or dovecote,
on the other hand, can acquire their bees and birds through Kinyan Chatzer,
and, therefore, it is possible to sell them for their future products, and
it is not considered Davar she'Lo Ba l'Olam.
(We will relate to how the Rambam deals with the Gemara that calls the sale
of doves a "Davar she'Lo Ba l'Olam" below.)
3. Even if the Rashba does argue with the Rambam, he might learn that our
Mishnah is not discussing one who sells the *dovecote itself* (i.e. a bird
house) for its birds, since the birds do not derive from the dovecote and
are a Davar she'Lo Ba l'Olam. Rather, the Mishnah is discussing one who
sells the *doves in a dovecote* for their offspring. That is, the word
"Shovach," or "dovecote," refers not only to the structure itself, but to
its occupants -- as the Ramban here writes (in Chidushim and in Milchamos).
The offspring do derive directly from the doves, and, therefore, they can be
sold just like a tree can be sold for its fruit. The Gemara earlier (79b)
calls the sale of future doves a "Davar she'Lo Ba l'Olam" because it was
discussing the sale of an *empty* Shovach. When, however, the Shovach
contains birds and is sold for the offspring of those birds, the Kinyan is
This might be also be the intention of the Rashbam at the beginning of the
The words of the Ra'avad seem to be indisputable. This requirement of
specifying the details of such a sale is indeed expressed by the Gemara
itself. The Gemara writes clearly that the sale is valid only when the
seller phrases the sale in a way that shows that he is selling the *tree*
for the use of its fruits (and not that he is selling the fruits
themselves), as the Gemara says in Bava Basra 147b. In addition, the Gemara
earlier (79b) teaches that when one sells the future doves of an empty
dovecote, they are considered a Davar she'Lo Ba l'Olam. How, then, can the
Rambam write that whenever a person sells "the produce of his dovecote," it
is *as if* he specified that he is selling the dovecote for its produce?
(See KESEF MISHNEH to Hilchos Mechirah 23:9, and BACH beginning of CM 213.)
The answer might be that the Rambam indeed makes the sale dependent on the
wording that is used. He maintains, however, that as long as the seller
relates the products to the hive, or the fruit to the tree, making it seem
like the products are an aspect of the hive or tree itself, the sale is
valid. It is as if the seller specified that he is selling the tree for its
fruit (a similar idea can be found in the RAN in Nedarim 13b, DH b'Omer
Ye'aser Pi l'Diburi). By saying that he is selling the fruit *of a tree*, or
the produce *of a hive*, the seller is viewing the products as *an aspect
of* the object which produces them and which is already in existence.
The case which *is* considered a Davar she'Lo Ba l'Olam is when the seller
specifies that he is selling "products *that come from* the hive," or "fruit
*that is produced* by this tree," implying that the sale is one of the
products or fruit, but not of the tree's fruit-producing ability.
According to this, the Gemara earlier (79b) may be referring to a sale in
which the seller specifies that he is selling "the products *that will
arrive* in this dovecote or hive," and not simply "the products of a
dovecote or hive." (M. Kornfeld)
(d) The NETZIV (in Meromei Sadeh) suggests based on numerous inferences that
a Rabbinic institution exists whereby any type of transaction that people
become accustomed to conducting on a regular basis gains validity, even if
that transaction involves the transfer of a Davar she'Lo Ba l'Olam.
HAGA'ON RAV YISRAEL ZEV GUSTMAN zt'l (ibid. 13:2) cites the HAGAHOS
MORDECHAI (end of Shabbos, #472, also cited in brief by the KETZOS
HA'CHOSHEN 201) who writes that a very similar point was debated among the
Rishonim. The MAHARAM said that when people become accustomed to a type of
transaction in which an object that is a Davar she'Lo Ba l'Olam is traded,
the trade becomes valid through the Kinyan of "Situmta," which gives
Halachic validity to commonplace practice (see Bava Metzia 74a). RABEINU
YECHIEL argues and says that even the principle of "Situmta" cannot make the
transfer of a Davar she'Lo Ba l'Olam into a valid transaction.