Hazon Ish and The Science of Grafting and Crossbreeding
Mordechai Halperin, MD
I. Resolving Doubt in the Understanding of Reality
opinion of the Gaon of Vilna regarding the importance of mastering science in
order to understand Torah “because Torah and science are bound up together” is of
great relevance when studying the laws of grafting plants. Rabbi Y.Y. Weiss
quoted a question he received:
There is a new kind of grain being grown today by taking the flower of one
species and inserting the pollen of another species. Is this prohibited like
grafting? This is similar to artificial insemination between species and it is
unclear to me whether the question can be answered on the basis of the opinion
of the Hazon Ish (Kela’im 2:16).
He seems to
mean that it is permitted if instead of growing it becomes part of the tree and
improves it. Since there is some doubt regarding the facts, one ought to be
The Opinion of the Hazon Ish
to understand this matter, we must study the opinion of the Hazon Ish,
who was dealing with a case where the facts are clear to any professional in
the field although laymen might not be familiar with them.
what the Hazon Ish (Kela’im 2:16)
resin is unlike prohibited crossbreeding because there is no prohibition in
inserting the seed of one species into another species. Crossbreeding is
prohibited only in living creatures, not in organs separated from them. On the
other hand, every cell of a shoot of a plant can potentially become a whole
plant. Any resin that similarly can grow into a plant also has the status of
being a plant itself and therefore may not be infused into another plant.
Ish added in a response to Rabbi Chanoch Z. Grossberg that grafting resin
into a crack of a tree is prohibited “only is the liquid turns into a shoot
The Opinion of the Hazon Ish and Reality
creature, whether animal or vegetable, consists of many interconnected cells.
In plants, a shoot can be removed and transplanted, thus producing a new plant
that will be genetically identical (viz. a clone) to the original.
Instead of transplanting the shoot in the earth, it can be grafted into the
crack of a tree. Such transplantation violates the prohibition against
planted in the earth will develop into a whole plant. On the other hand,
planting a single cell in the earth will not produce a plant at all; the cell
will die. Nonetheless, it is possible
today to take a single cell and grow it in laboratory conditions producing
plant tissue or a small shoot that in turn can be planted in the earth. In the
resin of a single tree, there are such cells that can be grafted by placement
in the crack of a tree. If the conditions in the crack correspond to the proper
laboratory conditions, such a cell from the resin will grow into a whole shoot,
which will be genetically identical to the plant from which it was taken. The
shoot will grow from the crack in the tree exactly as any other shoot that was
grafted there. All this was indeed possible in the past and this is what the Hazon
Ish was referring to.
infusing a certain resin into the earth will not produce a shoot, the Hazon
Ish developed the idea that infusing it into the crack of a tree is still
prohibited since it that environment it could indeed produce a shoot. This
prohibition is the same as grafting the shoot of one species of tree onto
event, the Hazon Ish explained that inseminating a germ cell of one
animal into an animal of a different species is permitted because the germ cell
is not considered a whole creature, unlike a shoot or resin containing cells
that can potentially become a whole plant. The prohibition of interspecies
grafting is violated only when a potentially whole plant is grafted onto a
plant of a different species. A similar principle applies in crossbreeding
animals, which is the source from which we derive the principles governing
of a male animal or plant is of course not a complete creature capable of
producing offspring unless it fertilizes a female’s egg. Only after
fertilization is a new cell formed that does indeed have the potential
to become a whole creature. Inserting the male seed into another species is
therefore not a violation of the prohibition of grafting as the Hazon Ish
explained that the prohibition is not violated when only “the [male] seed of
one species is placed into another.”
If so, it
is clear that Rabbi Shaul Yisraeli was right when he
permitted cross-pollinating plants
because the prohibition of crossbreeding applies only to crossbreeding two
potentially whole creatures, such as shoots or resin. On the other hand,
inseminating a male seed into a plant of another species is permitted.
When the Facts are Unclear
great rabbinic authorities are not always familiar with the facts. For example,
Rabbi Weiss wrote (Minhat Yitshaq 7:12b) in
connection with grafting that the facts were unclear. He was not sure whether
pollen is absorbed by the tree it fertilizes, in which case the procedure is
permitted, or whether it is not absorbed but rather grows as it is, in which
case the procedure is prohibited. His doubt regarding the facts forced him to
his forgiveness, Rabbi Wosner’s opinion is problematic because male pollen is
incapable of independently producing a new plant as resin or a shoot can.
Pollen does have the ability to fertilize a female egg producing a new
fertilized cell that in turn can produce a whole plant. Before fertilization,
the pollen is merely half a plant, incapable of reproduction as the Hazon
Ish explained. In this key distinction between whole and half creatures,
there is no difference between animal and vegetable life as the Hazon Ish
clearly wrote: “There is no prohibition in placing the [male] seed of one
species into another.”
B. Shick of Shklov (nephew of the author of the Sha’agat Arye) quoted the Gaon of Vilna in
the introduction to his Yesodot of Euclides
(den Haag, 5540): “Anyone who lacks a single measure of scientific knowledge
outside the realm of Torah lacks one hundred measures of knowledge within the
realm of Torah because Torah and science are bound up together.”
Minhat Yitshaq 7:12b.
 Huqqot ha-Sadeh, be-Talmei
Sadeh 14, quoted in Ma’adanei Erets: Hilchot Kela’im, Kela’im 1:5,
note 84, ed.: Rabbi Sh.Z. Auerbach (Jerusalem, 5763).
See also Derech Emuna, Kela’im 1:5, note 82,
the decision of the Hazon Ish, Rabbi Sh.Z. Auerbach
remained in doubt on this issue. He tended to be lenient as long as sowing in
the earth would not lead to sprouting (Ma’adanei
Erets: Hilchot Kela’im, Jerusalem, 5763, 1:5, sect. 10. s.v. kemo ken). It
seems, however, that he reversed his position in a letter to Prof. Avraham
because “in reality the field is sown with two diverse species.” Further, the
resin applied to the crack in the tree would not have sprouted if sown in the
earth (quoted in Prof. Avraham’s Nishmat
Avraham, second ed., Hoshen Mishpat
425:2 and in Minhat Shlomo, second ed., 97:27). It seems reasonable that
the manuscript underlying Ma’adanei Erets: Hilchot Kela’im antedates the letter to Prof. Avraham.
39a according to Lev. 19:19.
65-66, p. 67 (5759).
Shevet ha-Levi 9:224.
Shevet ha-Levi, ibid.: “In my opinion the matter
requires study for even so the male seed has the capacity to produce offspring
and we perform an act that produces a different species just like the resin
mentioned by the Hazon Ish.”
is the decision of Rabbi Sh.Z. Auerbach:
cross-pollinating is not an example of prohibited grafting because the pollen
has no capacity to sprout by itself. His nephew, Rabbi Y. M. Stern, quoted his
view in his Kashrut Araba’at ha-Minim, p. 182.
This is also the opinion of Rabbi Amar, the Chief Sefardic
Rabbi of Israel, in his Kerem Shlomo 2:1.