Yesterday, we noted the debate among the halakhic authorities as to whether the Torah obligation of tzitzit is limited to wool and flax garments, or applies to all garments. The Shulchan Arukh (O.C. 9:1), based on the position of the Rif and the Rambam, ruled that the Torah requires affixing tzitzit strings specifically to wool and flax garments; other garments require tzitzit only by force of Rabbinic enactment. The Rama, however, follows the view of Rashi and Rabbenu Tam requiring tzitzit for all four-cornered garments on the level of Torah obligation. As we saw, numerous halakhic authorities, including the Mishna Berura (9:5), maintained that in light of these different views, it is preferable to wear specifically a woolen tallit katan in order to fulfill the mitzva on the level of Torah law according to all opinions.
There is some discussion concerning the position of the Vilna Gaon in this regard. We noted yesterday that as recorded in Ma’aseh Rav (17), the Vilna Gaon reportedly wore a cotton tallit katan, a practice which is seemingly based upon the view of the Rama, that the Torah obligation of tzitzit draws no distinction between different materials. However, Rav Asher Weiss, in his discussion of this topic, cites those who argue that the Gaon did not, in fact, accept the Rama’s ruling. They claim that the Gaon wore a cotton tallit katan because he also wore a woolen tallit gadol over his clothing the entire day. Since he fulfilled the Torah obligation of tzitzit through his woolen tallit gadol, he specifically wore a cotton tallit katan under his clothing, so he could fulfill the entire day both the Biblical obligation of tzitzit and the Rabbinic extension of the mitzva. According to this theory, the Gaon in fact embraced the view of the Shulchan Arukh, and wore a cotton tallit katan so that he can fulfill the Rabbinic requirement in addition to the Biblical obligation which he fulfilled throughout the day by wearing his tallit gadol. As such, his practice does not set a precedent that may be followed by those who do not wear a tallit gadol the entire day.
Rav Weiss, in a brief parenthetical remark, questions the rationale behind this theory. Why, he asks, would there be any special value to specifically fulfilling tzitzit on the lower level of Rabbinic obligation? If the Gaon saw fit to wear two four-cornered garments throughout the entire day so he can fulfill the mitzva twice, rather than just once, then it would seem preferable to wear two garments that require tzitzit on the level of Torah law. Once he sought to increase his mitzva fulfillment by wearing multiple garments, he would, presumably, wish to achieve the higher level of performance by ensuring that both garments required tzitzit by force of the Torah’s command, and not merely by force of Rabbinic enactment. The notion that there value to specifically wearing a garment that requires tzitzit on the lower level of de-rabbanan (Rabbinic enactment) seems difficult to understand.
Rav Weiss adds that there are also those who proposed a different explanation of the Gaon’s practice. Possibly, the Gaon wore a flax undergarment beneath his tallit katan, and for this reason he specifically did not wear a woolen tallit katan. He may have felt that the prohibition of sha’atnez, which forbids wearing a garment made from both wool and flax, forbids even wearing a woolen garment directly on top of a flax garment. While it is commonly assumed that the sha’atnez prohibition applies only to wool and flax woven together, the Gaon may have felt that a woolen garment and flax garment worn one over the other qualify as sha’atnez. Thus, his decision to wear a cotton tallit katan may be entirely unrelated to the debate between the Shulchan Arukh and the Rama, as it stems from concerns of sha’atnez.