R. Hunah (Hulllin 9a) states that while alive, an animal is presumed to be prohibited (בהמה בחייה בחזקת איסור עומדת) until it becomes known how it was slaughtered, but if shehitah has been performed on the animal, it is presumed to be permissible until a defect in the animal or in the shehitah is discovered. This statement is cited in relation with a teaching in a Baraita that if the simanim of an animal upon which shehitah was performed were not inspected, the flesh of the animal may not be eaten. According to one opinion in the Baraita, the animal is considered a tereiphah, and according to another opinion, it is considered a neveilah. The Gemara then posits that the two opinions in the Baraita disagree about how to understand R. Huna’s statement. The opinion that the animal is a tereiphah holds that there is a presumption of impermissibility (hezqat issur) but no presumption of ritual impurity (hezaqt tum’ah) while the opinion that the animal is a neveilah holds that, given the hezqat issur, the death of the animal renders it a neveilah.

The source of the statement of R. Huna is found in the Sifra and is quoted by Rashi at the end of parashat Shemini (Leviticus 11:47):

“To distinguish between the impure and the pure, between a creature that may be eaten and a creature that may not be eaten” (להבדיל בין הטמא ובין הטהור בין החיה הנאכלת ובין החיה אשר לא תאכל): Is it necessary to say between a donkey and a heifer (בין חמור לפרה) and between a gazelle and a wild ass(בין צבי לערוד) ? Rather between cutting half of the windpipe and cutting most of the windpipe (בין נשחט  חציו של קנה לנשחט רובו) and between conclusive signs of a fatal defect and inconclusive signs of a fatal defect(בין שנולדו בו סימני טרפה כשרה לנולדו בו סימני טרפה פסולה) .

But the latter distinctions made by the Sifra also seem superfluous, inasmuch as we know from another source that a majority – not just a half — of a siman must be cut for a shehitah to be valid. And we also know that there are some potentially fatal defects that do not render the flesh of an animal unfit for consumption, which is why a halakhah le-moshe mi-sinai enumerates those defects that do render an animal a tereiphah and its flesh unfit for consumption. So, what does the verse (להבדיל בין הטמא ובין הטהור בין החיה הנאכלת ובין החיה אשר לא תאכל) come to teach us? The verse must instead be understood to require an animal to be inspected after shehitah has been performed to determine if its simanim were sufficiently cut. Moreover, in the verse “טמא” precedes “טהור ”, teaching us that, before inspection, the animal is presumed to be ritually impure, and unfit for consumption, because of the hazaqah that no shehitah has been performed on a live animal, the hazaqah remaning in place until the inspection after shehitah. Similarly, the distinction ” בין החיה הנאכלת ובין החיה אשר לא תאכל” teaches us that, if the inspection reveals a potentially fatal defect in the animal, we assume that the defect occurred after shehitah, because, in the verse, “חיה הנאכלת” precedes “חיה אשר לא תאכל”. Thus, all the laws stated by R. Huna can be inferred from the Scripture. Moreover, the Sifra follows the opinion that, without inspection after shehitah, the animal has the status of neveilah and is ritually impure, contrary to the opinion that the animal is a tereiphah and ritually pure.

But it might be argued that the hazaqot concerning issur and tum’ah offset one another. While an animal is alive, there is a hezqat issur concerning its flesh and a hezqat taharah concerning the animal. To maintain the hezqat issur requires that, after the animal’s death, we assume that a valid shehitah has not been performed, while to maintain the hezqat taharah requires that we assume that a valid shehitah was performed. Since maintaining the two hazaqot simultaneously requires contradictory assumptions to be made, the permissibility of the animal’s flesh and its ritual purity are halakhically indeterminate. Accordingly, the Rambam (Hilkhot Shehitah 3:15) rules that when a siman was broken and it is unknown whether the break occurred before or after shehitah was performed, the animal has the status of a sapheq neveilah. He further rules generally (3:18) that every doubt concerning the validity of a shehitah renders the animal a sapheq neveilah. But the Rambam rules (1:12) that, if the simanim were not inspected, the animal is certainly considered a neveilah.

Perplexed by this ruling of the Rambam, the Pri Megaddim questioned why a failure to check the simanim, unlike other doubts concerning shehitah, renders the animal a neveilah rather than a sapheq neveilah. It would seem that this problem is the reason why the Tosaphists write (Hullin 9a) that the flesh of an uninspected animal would be Biblically permissible based on the premise that most (rov), shehitot are performed properly, and while consumption of the animal’s flesh is prohibited rabbinically, the rabbis, not wanting to spread ritual impurity, were lenient in not decreeing such an animal to be ritually impure. But Rashi apparently does not consider the prohibition of the flesh of the animal rabbinic, because, as suggested above, the verse (Leviticus 11:47) from which an inference is drawn is superfluous, so that the inference is conclusive, not a mere asmakhta.

This dispute between Rashi and the Tosaphists reflects their different understandings of how a hazaqah is maintained. Does the hazaqah maintain a given halakhic status or does it maintain a given factual premise? The Tosaphists believe that the hezqat issur of the flesh of an animal derives from a factual premise that the animal has not been slaughtered, but they also believe that any hazaqah concerning halakhic status, whether a hezqat issur/heiter or a hezqat tum’ah/taharah, is maintained even if the factual premise underlying the hazaqah must be changed. For example, to maintain the hezqat tum’ah of a person, one would have to posit that the red heifer whose ashes had been sprinkled upon him had been a tereiphah, nullifying the ashes incapable of dispelling ritually impurity, or to maintain the hezqat heiter of a fetus in the mother’s womb (not yet having issued from the womb) one would have to assume (after the fetus is born) that the mother had in fact given birth previously and that the newborn was not the first issue, even though the two assumptions are contradictory. Accordingly, because the hazaqah that an animal is ritually pure while alive is so powerful, it is maintained even after death by assuming that the animal died because of a proper shehitah. That is why the Tosaphists raised the question that the hezqat taharah should cancel the hezqat issur, and the status of the animal should be that of a sapheq shehutah with respect to both issur and tum’ah. The Tosaphists were therefore compelled to say that, according to the opinion in the Baraita that the animal has the status of a tereiphah, the animal is Biblically permitted because in most cases shehitah is performed properly. Nonetheless, a rabbinic stringency prohibits consumption of its flesh, but does not render the animal itself ritually impure, because a decree of ritual impurity would cause excessive hardship. But, the Tosaphists explain, according to the opinion in the Baraita that the animal has the status of a neveilah, the rabbinic stringency applies equally both to issur and to tum’ah.

Rashi, however, believes that upholding a hazaqah requires us to assume that, without contrary evidence, the factual situation underlying the hazaqah continues as before even if that implies a change in halakhic status. This understanding corresponds to the opinion in the Baraita that an animal upon which shehitah was performed is considered a neveilah until it undergoes inspection. Because the flesh of a live animal is prohibited as eiver min ha-hai, the hazaqah that the flesh is prohibited remains unless a valid shehitah is performed on the animal, immediately eliminating the prohibition of eiver min ha-hai even before death. But after death, although the prohibition of eiver min ha-hai is no longer conclusively in force, the hazaqah that a valid shehitah has not been performed remains. So, while the hazaqah that a valid shehitah was not performed remains in place, the death of the animal implies that the animal is a neveilah, rendering the animal ritually impure. Although the animal was ritually pure before death, the hazaqah of ritual purity cannot survive the animal’s death, because a hazaqah of ritual purity cannot be maintained after death without evidence of a valid shehitah, which is lacking unless and until the animal is inspected.

According to Rashi, it is the contrary opinion in the Baraita — that the dead animal is a tereiphah, whose flesh is prohibited but isn’t ritually impure – which assumes that, without contrary evidence, we maintain the hazaqah the animal had while alive, even if doing so requires positing a new factual basis for the hazaqah, and even if maintaining the hazaqah requires making contradictory factual assumptions (i.e., that the shehitah was invalid so that its flesh is prohibited, but, to maintain its ritual purity, that the shehitah was valid). The seemingly redundant phrase that the animal is a tereiphah and its flesh is prohibited (טרפה ואסורה באכילה) is therefore appropriate, teaching us that the animal’s halakhic status can’t be more stringent than that of an animal that is certainly a tereiphah, and, therefore, not ritually impure.

Nonetheless, the doubtful status of the animal arises because its simanim were not inspected, so that, lacking evidence that a majority of the simanim were cut, we can’t assume that a valid shehitah was performed on the animal. It could therefore be argued that the prior hazaqah that a shehitah was not performed on the animal remains in place, so that the animal is rendered a neveilah upon death, the prior hezqat taharah being nullified once the animal dies. But when an inspection shows that the majority of the simanim were cut, except that we are unsure if a valid shehitah was performed, with no hesitation or application of force, or a nehirah was performed. The prior factual hazaqah that a valid shehitah was not performed is inconclusive, because there is also a factual hazaqah that a nehirah was not performed. Since we know that the animal was slaughtered by one of these two methods, maintaining the hezqat issur requires assuming that the animal was slaughtered by nehirah, while the hezqat taharah requires assuming that the animal was slaughtered by a valid shehitah. According to the opinion in the Baraita that we always maintain the previous halakhic status unless we have clear evidence to the contrary, the flesh of such an animal is prohibited, but it remains ritually pure. However, according to the opinion in the Baraita that it is a factual, not a halakhic, hazaqah which is maintained, no hazaqah is in effect, because the factual situation whether the animal was slaughtered by a valid shehitah or by a nehirah cannot be determined.

Therefore, according to the Rambam, every doubt concerning shehitah that cannot be resolved by inspection renders the animal Biblically permissible to be eaten but prohibited rabbinically. The Tosaphists, however, maintain the opposite position that when the animal has not been inspected, the doubt is resolved by the assumption that in most cases shehitah is performed properly, so that the animal is a prohibited, by rabbinic edit, as a neveilah. However, if the doubt is whether a defect found by inspection already existed before shehitah or was created after the shehitah, then, based on the prior hazaqah while the animal was prohibited before shehitah was performed, the animal is considered, even under Torah law, to be a neveilah.