Why is such an act permitted? Even though the person does not have
*intention* to have Hana'ah from the clothes he is wearing, it is
*inevitable* that he will be warmed by them in winter and protected from the
sun in the summer -- i.e. it is a "Pesik Reishei." We find that Rebbi Shimon
agrees that a Pesik Reishei is forbidden, although one does not *intend* to
do the forbidden act! ("Davar sh'Eino Miskaven" only means that one may
perform an act which *may* unintentionally cause the transgression of a
Torah prohibition; not an act that will *certainly* cause such a
transgression.)
Similarly, the Gemara earlier (25b) says that both Abaye and Rava agree that
"Lo Efshar v'Lo Mechaven," a situation in which getting Hana'ah is
unavoidable and one does not have Kavanah for the Hana'ah, is Mutar
according to Rebbi Shimon. Why is it Mutar if it is a Pesik Reishei
(inevitable) that he will get Hana'ah?
(a) TOSFOS earlier (25b, DH Lo) and in Shabbos (29b) explains that it must
be that when the Mishnah says that one may wear clothing of Sha'atnez, it
refers to a case where one does so in a way that he *could avoid* getting
Hana'ah from the garments (for example, he could wear it without it covering
him completely). Since it is not definite that he will get Hana'ah it is not
a Pesik Reishei. If, however, it is not possible to avoid getting Hana'ah,
then not having Kavanah would not permit it because it is a Pesik Reishei.
Similarly, when the Gemara earlier said that "Lo Efshar v'Lo Mechaven" is
permitted, it did not mean that it is entirely impossible not to get
Hana'ah. Rather, it means that he cannot accomplish what he would like
without doing an act that is *very likely* to cause him Hana'ah. Thus, it is
not a Pesik Reishei.
(b) The RAN in Chulin (32a of the pages of the Rif) explains that ours is
indeed a case where one is certainly going to benefit from the Isur; the
Hana'ah is unavoidable. One will certainly derive benefit from wearing the
garment of Sha'atnez, or one will certainly smell the aroma of Avodah Zarah.
Regarding any other type of Isur, such a case would be a Pesik Reishei and
be prohibited. When it comes to a prohibition of deriving *benefit* (Isur
Hana'ah), though, the act is Mutar as long as one does not have Kavanah,
even if it is a Pesik Reishei.
The Ran cannot mean that if one does not have Kavanah for experiencing
Hana'ah it is not considered Hana'ah (that is, one only experiences Hana'ah
when he wants to), because then even Rebbi Yehudah would agree that it is
Mutar to derive benefit from Kil'ayim or Avodah Zarah without Kavanah; it
should have nothing to do with the laws of Davar sh'Eino Miskaven. Rather,
perhaps the Ran means that even though one seems to be definitely getting
Hana'ah, as long as he does not have Kavanah to get that Hana'ah, it is
*never certain* that he will have Hana'ah. Why? Since, by not having Kavanah
to have Hana'ah, it is *possible* that he will indeed not experience
Hana'ah. Acts involving Isurei Hana'ah can never be considered a Pesik
Reishei because one *might* avoid having Hana'ah altogether; it is
therefore a normal case of Davar sh'Eino Miskaven.
(c) RABEINU CHAIM HA'LEVI on the Rambam (Hilchos Shabbos 10:17) explains the
Ran differently. He suggests that even if one is definitely going to get
Hana'ah, it is still possible to say that it is Mutar because of the laws of
Davar she'Eino Miskaven. Just because one is definitely going to get Hana'ah
does not always make an act Asur. For example, the Aruch (Erech "Pesak," see
Tosfos Kesuvos 6a) rules that an act which is a Pesik Reishei "d'Lo Nicha
Lei," which a person does not want, is Mutar, even though it is definitely
going to occur. It is Mutar because he does not have intention to do it and
it is not in the least his desire for it to occur, although it will
definitely occur. Similarly, the Ran means to say that when it comes to
Isurei Hana'ah, even a Pesik Reishei is judged as a normal Davar sh'Eino
Miskaven.
(Perhaps this may be understood as follows. Normally, a Pesik Reishei is
prohibited since one *must* be intending, to some degree, to perform the
Isur -- since he has a clear interest in the by-product of the Isur. With
Isurei Hana'ah, though, this is not so. The interest one has in the by
product (i.e. the Hana'ah) that comes from the Isur is not concrete enough
for us to assume that he must be intending to perform the Isur to attain
that by product. Therefore his act remains a Davar sh'Eino Miskaven under
all circumstances -M. Kornfeld)