הלכה על יבמות 16:1

Some background is necessary to understand the Gemara’s case. If a man dies childless, the Torah (Devarim 25:4-11) obligates the brother of the deceased either to marry the widow (yibum) or participate in a ceremony in which he officially declines to marry her (chalitzah). If the deceased left offspring, however, there is no obligation for his brother to perform either yibum or chalitzah. The Mishnah (Yevamot 16:1) discusses a case where a woman’s husband died childless and the deceased husband did not have a brother, thus avoiding the requirement for yibum or chalitzah. However, the deceased husband’s mother remains alive in a distant land where the wife could not communicate with her. The Mishnah teaches that the wife need not be concerned that the mother gave birth to a male child who would be required to perform yibum or chalitzah because of what may be construed as a s’feik s’feika: “Perhaps she miscarried and perhaps she gave birth to a female.” It thus appears that such a s’feik s’feika is valid.¹¹Alternatively, the Gemara’s case could be understood as employing the principle of rov, as we noted earlier from the Chatam Sofer. Rav Zalman Nechemia Goldberg, however, understands s’feik s’feika to be merely a more potent form of rov, and thus one cannot distinguish between the two, since they are identical concepts. For further discussion of this issue, see Aruch Hashulchan Y.D. 110:96-98.