Responsa for Gittin 4:8
רוב בקיאין הן ואפילו לר"מ דחייש למיעוטא סתם ספרי דדייני מיגמר גמירי ורבנן הוא דאצרוך והכא
But presumably the rule that one witness is sufficient where the question at issue is a ritual prohibition applies for instance to the case of a piece of fat of which we do not know whether it is permitted or forbidden, there being no prima facie ground for declaring it prohibited. Here, however, since there is prima facie ground for assuming the prohibition regarding a married woman,<span class="x" onmousemove="('comment',' Since the recipient of the Get is a married woman she is prima facie (until we know that the Get is valid) forbidden to all other men. ');"><sup>8</sup></span> the question becomes one of prohibited sex relationship, and for disproving such a relationship the evidence of two witnesses is required?<span class="x" onmousemove="('comment',' V. Sot. 3. ');"><sup>9</sup></span> — Most [of the Jews abroad] are acquainted [with the rule of 'special intention'].<span class="x" onmousemove="('comment',' Hence we do not suspect the husband of having broken this rule. ');"><sup>10</sup></span> And even if, following the practice of R. Meir, we take account of the exceptions, [it will make no difference.] for most of the scribes of the <i>Beth din</i> know the law, and it was the Rabbis who [on their own authority] insisted [on this declaration], and in this case,