Can we combine two rulings that are based on different reasons?
Rabbi Shmuel Wise
It is no easy task to formulate a final ruling on so many issues that are dealt with in the Gemara. It is truly a blessing when the gemara concludes: “The law is…” for in these instances we are provided with clear practical guidance on the matter at hand, and most often such rulings will be directly codified into the Shulchan Aruch as such…nice and easy. But, of course, there are innumerable instances where the gemara does not issue a final ruling, or we might have contradictory conclusions between different gemoros, or a situation which isn’t directly addressed by the Gemara at all (think microwaves on Shabbos or constructing eruvin in modern-day cities). And so disputes about how to rule have arisen across the gamut of halachah—from the early Geonim until the arbiters of halachah (or poskim) of our time.
One of the most basic tools in the kit of a posek is the method of tziruf, combination. That is, the posek will marshal as many proofs as possible in support of his ruling; for surely a ruling backed up by ten gemoros has much more teeth than a ruling only supported by one. On Wednesday’s daf this week (36a) the Amora, R’ Oshaya, utilizes this method of tziruf. The case under discussion deals with the question of whether blood from shechitah makes food susceptible to tumah, ritual impurity. Even on the assumption that shechitah blood does have this capacity in general, the gemara discusses what would happen if the blood was no longer present on the food by the time the shechitah act was completed. On the latter question R’ Chiya (according to R’ Pappa; see there) rules that such blood does not make the food susceptible to tumah and on the first question there is a dispute between Rebbi and R’ Shimon (Rebbi holds that shechitah blood always has this capacity).
Regarding the practical halachah in a case where the blood was no longer on the food by the end of the shechitah, R’ Oshya makes the following argument: Both R’ Chiya and R’ Shimon agree in this case that the blood cannot make the food susceptible against the sole opinion of Rebbi who says that the gourd would become susceptible even in this case. Since it’s “two against one,” the halachah is that the gourd did not become susceptible to tumah.
Many poskim (including: Maharik, R’ Akiva Eiger, Noda Beyhuda, Lev Aryeh) prove from this gemara that it is acceptable to combine different opinions about a halachah—even if the opinions are based on different reasons. For that is exactly what we have in this gemara: Though R’ Chiya and R’ Shimon agree that the gourd didn’t become susceptible to tumah here, they each say so for completely different reasons. Yet the Shach (Yoreh Deah, Siman 242, “Summary of Deciding Halachah”, letter 6) states plainly that we cannot combine two opinions to decide the halachah if they are based on different reasons. Surely the Shach was well aware of our gemara (in addition the Noda Beyehuda cites a Rambam who appears to take the same position as the Shach), so what would the Shach say in response to this gemara?
Perhaps the Shach would argue that our gemara should not be interpreted as a rule meant for broad application. For the Shach would emphasize that the strength of R’ Oshaya’s point is significantly weakened by the fact that the two opinions which he seeks to combine employ mutually exclusive reasons. Now clearly, along with his total grasp of all of the aspects of the case and his “Amora’s license,” R’ Oshaya felt that we can utilize the intersection of the two opinions to “tip the scale” and formulate a ruling. However, the Shach would argue, to base a ruling entirely on combining two opinions who argue with each other’s reasoning is not an acceptable practice.