Book of the Upright
They say that it is written: The nakedness of thy father’s wife’s daughter, begotten of thy father—she is thy sister, thou shalt not uncover her nakedness (Leviticus 18:11). This daughter of the father’s wife, they say, is not really begotten of his father, because if she were Scripture would have related her to him instead of to his wife. It thus necessarily follows that she was begotten of someone else, and yet Scripture made her his father’s daughter. Now it is evident that except for her mother’s marriage to his father there would have been no way to make the daughter a child of his father, and if her mother’s marriage to his father had not made the mother and the father one individual, the mother’s child would not have become the father’s child as well.
Know, then, that what they have said about this is not correct, since the falsity of what was just said about this verse has been demonstrated in more ways than one, for different scholars have interpreted it in various ways, and if it were our purpose to explain this verse, it would have been proper to recount all of them and to discuss them. Our design, however, is not to do this, but rather to explain—granting for the sake of argument the correctness of their interpretation of the verse—that their aforementioned conclusion that the father and the mother, of the son and of the daughter respectively, had become one individual is not cogent.
Now from their reasoning it follows that if the wife and her second husband have become one individual, then she and her first husband had likewise become one individual. This being so, it is impossible that the wife and the daughter should be the family of each of the two husbands without the two husbands also becoming thereby one individual; rather is it to be assumed that the one husband and the other also become one individual, since the child of the one becomes the child of the other as well.
This being proven, it follows that if the first husband had a wife other than the one who later married the second husband, this other wife and the second husband also become one individual, because she and her husband are one, and her husband and this man who is the second husband are also one, wherefore the second husband and the other wife of the first husband are likewise one. The same would be true if this other wife of the first husband subsequently had another husband, and if this latter had another wife, and so on, since the same cause governs the relationship of all of them. In this event, the relatives of these various husbands and wives would be forbidden in the same way as the relatives of the original wife who is the mother of the daughter referred to in Scripture.
According, then, to this principle a person has no less than five fathers, to wit:
1) The real father.
2) The mother’s new husband who, by marrying the mother, becomes the father, just as the husband of the mother of the daughter is the daughter’s father, for it is impossible that Scripture should call her his daughter without his becoming her father. The term “husband of the mother” applies equally whether the mother’s child is male or female; the term “mother” applies equally whether the mother is the real father’s widow or his divorced wife; and by analogy to the daughter of the wife of the father becoming a sister, the son of the new husband of the mother becomes a brother and the daughter of the new husband of the mother becomes a sister. These two fathers alone are fathers.
3) The third father is the husband of the wife of the father in accordance with what we have said above that if two men successively married to the same woman become one individual because each one of them has become one individual with that woman, it necessarily follows that if one of them is the father of A, the other man also is A’s father; otherwise their principle that a woman acting as intermediary between two successive husbands makes them one individual is demolished.
4) The fourth father is the man who marries the other wife of the husband of the mother, which is proved thus: the husband of the mother is A’s father, on the basis of what has been demonstrated above that if the woman’s daughter becomes the child of the husband of her mother, he conversely becomes her father. Now if the husband of the mother is the father, and if he and the husband of his other wife have become one individual, as shown above, then the husband of the other wife also is the father, since he and the stepfather, i.e., the husband of the mother, are one individual.
5) The fifth father is any man who marries any other woman who at any time was married to one of the aforementioned four fathers, since by being married to the latter she and he had become one individual; consequently she likewise makes her second husband one individual with whichever of the four fathers she had formerly been married to. And since those four are fathers, he too becomes a father.
At this point they limit the fatherhood to these five fathers without any compelling reason for such a limitation, since the fifth father likewise may at one time have been married to a woman other than those referred to before, who had previously been married to another man. In this case this man and the fifth father would, through the mediation of this woman, have to become one individual; and since this fifth person is a father, why should not the previous husband of the other wife likewise be one? And so forth, in this same manner. If they should admit the cogency of all this, they will at least have followed their principle. If, on the other hand, they do not follow in this case that which they themselves have made a basic principle, they themselves will have violated it. If they should retort that in their view it is highly improbable that this sixth man should be forbidden, the answer would be that there is no possible way for it to be improbable if the principle which leads to it is assumed to be sound.
Credits
Published in: The Posen Library of Jewish Culture and Civilization, vol. 3: Encountering Christianity and Islam.