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Class Notes - Class #2

Mitzvah #155 tells us to examine fish to make sure they have the signs of fish we are permitted to eat, and #156 tells us not to eat fish that lack those signs.  If a fish has fins and scales we are allowed to eat it.  Any fish with qualifying scales also has fins, so the real issue is the scales.  One scale on the cheek, tail, or under the fins, or two scales elsewhere, demonstrate that the fish has scales.  If the fish has scales during some part of its life cycle but not others we are permitted to eat the fish; the scales need not be present during the fish’s entire life.

            The author mentions the issue of defining positive and negative mitzvot, and the issue of whether violation of a positive mitzvah is punishable.  He says he will return to this topic in mitzvah/essay #573.  Clearly the author has a careful plan for the rest of his book.


Mitzvah #157 deals with which birds we are allowed to eat.  The Torah gives a list of 24 kinds of birds that we are not allowed to eat; presumably, we may eat all the rest. (Some of those 24 birds on the list are categories that include many types of birds.)  That list would be clear if we could be sure of the identity of each of the 24 types.

 There is no accompanying mitzvah to examine the signs of permissible birds since there are no signs explained in the Torah.            The author says that if someone can identify the 24 forbidden types of birds, that person can eat any other type of bird he or she finds.  But many people cannot identify those 24 types of birds. 

The rabbis identified four factors to help distinguish birds we may eat from birds we may not eat.  1.  Whether or not a bird is predatory.  The author seems to sum up this characteristic by saying a predatory bird is one that attacks with its claws.  2.  Whether the bird has an “extra talon”; according to the Encyclopedia Judaica this may be whether the bird’s back talon is high on its leg and/or whether or not the bird’s front center talon is longer than the others.  3.  Whether or not the bird has a crop, a broad place at the end of its gullet where the bird collects its food.  4.  Whether or not the bird’s gizzard can be peeled easily.

 Predatory birds are prohibited, although rishonim disagree about the definition of a predatory bird.  If a bird has all of the three final factors, we may eat it and need not worry about whether it is predatory.   No special expertise or tradition is needed for someone to apply these two rules.   A non-predatory bird with none of the final three factors is also permitted.  If a bird has one of the last three factors and is not predatory or a crow or raven, we are permitted to eat it.  There are two birds that are exceptions to this rule, but those two birds don’t live near people so they are no problem. (Note that only someone who can recognize a crow or raven can apply this rule.)   On the other hand, a non-predatory bird with two of the other three factors is suspect and we should consult an expert before eating it.  Finally, if the Jews in an area have a tradition to eat a given type of bird, other Jews can rely on that tradition to determine which birds he or she may eat.  If there is doubt about whether or not a given bird is permitted, consult the local tradition.

That is a confusing list.  The reason the criteria are so confusing is that they are descriptive, not prescriptive.  The rabbis are trying to describe what the 24 prohibited birds have in common, and that isn’t easy to do.

That leaves the interesting problem of birds that were not known in the ancient Near East, birds from the New World, Australia and New Zealand.  If the Torah’s list of prohibited birds is exhaustive, any of these birds would be permitted.  But the Torah could hardly include in its lists birds that did not have names because they were unknown.  Rabbi Dr. Ari Zivitofsky has written on how communities decided which of these birds to eat and describes it as an ad hoc process.  (You can find his article “Is Turkey Kosher?” on


Mitzvah #158 requires that we examine the characteristics to decide which locusts, “hagavim,” we are allowed to eat.  The author lists eight permitted types.  Experts can determine which are permitted by looking for three characteristics: 1.  Four wings that cover most of the length and surface of the body; 2.  Four legs; and 3.  Two upper jointed legs.


Mitzvot #162 – 165 cover the kashrut of bugs, and the topic is more complex that one would expect.  The author also uses this series of mitzvot to introduce some new concepts.  Let’s summarize and understand what the author has to say about these topics and then go on to make some general comments.

            Our author explains that mitzvah #162 prohibits us from eating critters that swarm on the earth; mitzvah #163 prohibits us from eating critters engendered in picked produce who then exit the produce; mitzvah #164 prohibits us from eating critters that swarm in the water; mitzvah #165 prohibits us from eating critters engendered in rotting material.

            Start by looking at the source verses, Leviticus 11:41-44.  These verses portray these forbidden critters as disgusting, and say that our eating them will make us disgusting.  The verses connect eating these critters with issues of tumah.  They do not specifically list the different kinds of forbidden critters; the author, following Rambam, has associated each mitzvah with a different type of critter.  The verses describe the forbidden critters as “hasheretz hashoretz al haaretz,”  “ a swarming creature that swarms on the earth.”  Only a sheretz that swarms on the earth is forbidden.

            Mitzvah #162 directly prohibits eating a sheretz that swarms on the earth.  (Obviously this does not forbid the hagavim from mitzvah #158.)  These fall into two categories.  Eight of these sh’ratzim are also sources of tumah.  Someone who intentionally eats a lentil’s volume of one of those is punishable with malkos for violating this mitzvah.  Someone who intentionally eats a k’zayit, an olive’s bulk, of any other sheretz that swarms on the earth is punishable with malkos.  Why the difference in amount?  The author says that all shiurim, definitional sizes, are “halachah l’mosheh misinai,”  “laws deriving from Mosheh at Sinai.”  In other words, they are ancient traditions for which no reason is given.

The source verses prohibited our eating a sheretzhashoretz al haaretz,” that swarms on the earth.  This explains the close distinctions in mitzvah #163, which forbids us from eating some critters engendered in produce.  If a sheretz is engendered in a produce still on the plant, the sheretz is swarming on the earth, in particular on a plant attached to the earth, and the sheretz is therefore forbidden.  If a sheretz is engendered in picked produce and then emerges from the produce, the sheretz is swarming on the earth once it emerges and is therefore forbidden.  It remains forbidden even if it re-enters the produce after having come out.

Ramban thinks that the sheretz is not forbidden until the sheretz comes out of the produce and onto the earth.  Rambam thinks that the sheretz is forbidden immediately as it emerges from the fruit even if it stays on the surface of the fruit. 

The author considers several close cases in addition to the one we just described.   Let’s say the sheretz flies out of the produce and someone eats it before it lands on anything.  Or the sheretz emerged from the produce and died before it hit the earth and was subsequently eaten, so it never got a chance to “swarm on the earth” because it died before it got a chance to do so.  In all these cases one could argue the sheretz had swarmed on the earth, or one could argue the sheretz had not swarmed on the earth.  The author says something odd about these cases:  he says they are “assur misafek,” “prohibited because of doubt.”  The doubt here seems to be that the author does not want to decide.  That is unusual.  Typically our author chooses one approach or the conflicting approach, and if he does not want to decide he explains both conflicting opinions.

Note that we are allowed to eat critters engendered in picked produce as long as the critters are still in the produce. Therefore, according to our author, we are allowed to eat worms in dates, dried figs, lentils and beans, since the worms are engendered in the produce after it is harvested and do not emerge.  This seems more like a list of examples than like a complete list.  But the author is squeamish.  He suggests that eating these critters might result in “shikutz hanefesh,” abomination of the soul.  He does not explain what he means by that.

It may not always be clear if a sheretz in produce was engendered while the produce was still on the plant and attached to the ground, in which case we are not allowed to eat it, or after the produce was harvested, in which case we are allowed to eat it.  The author says in that case we are required to check, presumably by checking sample produce before picking it to see if the sheretz is present at that point.  But that may not solve the problem, as the sheretz might be present in the produce but still too small to see.  In that case, we can harvest the produce and preserve it for twelve months.  By that time, any vermin will have deteriorated enough that the vermin are no longer considered shratzim, they are just considered dirt.  Then we are permitted to eat the produce.

After considering vermin in produce, the author goes on to discuss vermin in animals.  (This ongoing discussion might be much more attractive to teenaged boys that it seems to us.)  The issue continues to be whether the vermin ever swarmed on the earth, or whether they were engendered in the animals and stayed there, never having swarmed on the earth.

Thus, worms in the digestive track of fish are prohibited because, presumably, they came from outside the fish and were eaten by the fish.  Practically, we discard the fish guts when cleaning the fish so we would discard these in any case.  Worms in the flesh of the fish or between the flesh and skin are fine since, presumably, they were engendered there.

Mammals are different, though, because we are obligated to ritually slaughter mammals before we eat them.  Worms in the digestive tract of a mammal are prohibited because, presumably, the mammal ate them.  Worms in the flesh or brain of the mammal are also forbidden because they would require independent ritual slaughter.  Distinguish that case from the case of a pregnant animal that is ritually slaughtered, where the fetus is considered part of the mother and does not normally require separate ritual slaughter.  (We saw this topic in more detail in the prior class.) This distinction is based on midrash halachah which justifies each of these results.

Then the author considers critters in water, again determining which are considered shratzim that swarm on the earth.  Consider water found in vessels (cups, pots, pits, ditches, caves, etc.) that contain critters engendered in the vessels: we are permitted to eat the critters since they have been in the vessel and in the water but not on the earth.  Even if the critters come out of the water, we are still permitted to eat them, as long as they do not exit the vessel.  But if the critters get to the outside of the vessel, we are not permitted to eat those critters.  For example, let’s say we have beer in a vessel with straw covering the spout.  When pouring the beer, we run the risk that a critter from the beer will get caught on the straw and then fall back into the vessel.  Had the critter stayed in the vessel we would be allowed to eat that critter, but once it gets caught on the straw it has swarmed on the earth and we are no longer allowed to eat it, even if it falls back into the beer.  Obviously the beer drinker has to be careful.  The author says we should avoid pouring the beer at night when we cannot see clearly whether a critter has gotten caught in the straw.  Presumably we could pour the beer during the day.  Or we could remove the straw from the pour spout.

Having defined which critters are permitted and which forbidden, the author goes on to consider what happens when we find a forbidden critter in our food.  Of course, the simple solution to that problem is to remove the critter if possible.  Earlier the author introduced the concept of bittul.  If some forbidden food gets mixed with permitted food, the entire mixture is permitted if the forbidden part does not change the taste and is a de minimis portion of the whole. 

Our author explains an exception to the general rules of bittul.  A “beria,” a “whole animal,” is never considered batel, no matter how small a portion of the mixture that creature is.  A beria is a whole animal; if the animal is missing even a small part of its body, the normal rules of bitul apply.  It is easy to see why the author puts this topic into this essay.

Further, an animal is only a beria, and not batel, if it was forbidden from the time it was formed.  If an animal becomes forbidden sometime during its lifetime, the animal is a beria while it is alive, but after it dies the normal rules of bitul apply.  Many of the shratzim covered by this mitzvah are forbidden from the time they are formed, so if they turn up in food, they cannot be batel. (They can, however, be removed from the food.  Any animal parts that remain or any flavor they impart would be subject to the normal rules of bitul.)  Distinguish that from a whole animal that was permitted as food but became forbidden during its lifetime.  A good example is a cow that became a treifah.  That animal is considered a beria while it is alive but not after it has died.  So the treifah cow would be batel after it died even if it is whole, but could not be batel while it was alive.

Beria is an exception to the rules of bitul and is also an exception to the shiur for how much forbidden material one has to intentionally eat in order to be punishable.  Normally, for most things, one is only punishable for eating a k’zayit of forbidden food.  However, if one intentionally eats a complete forbidden animal, one is punishable even if the volume of the animal is less than a k’zayit.  However, someone who intentionally eats sections of forbidden shratzim will not be punishable until the person has eaten a k’zayit.

The author cites a source for this rule.  Actually, he explains, there is an apparent disagreement between the Talmud Babli and Talmud Yerushalmi on this issue.  The Yerushalmi cites an opinion that a beria, specifically a mouse, is batel one in 1000.  The Bavli says a beria is never batel.  In a conflict between the Bavli and Yerushalmi, we typically follow the Bavli.  Hence, a beria is never batel. (The author is introducing us to a new content concept as well as a new process concept.)

Actually, the notion that a beria cannot be batel is based on the Mishnah that lists eight items that are never batel because they have a special respected status.  A whole animal has special respected status.  The author lists the eight items from the Mishnah, but we would need lots more social context to conceptualize what makes these items special.

 Rambam explicitly says that anything with the same social status as the items on this list is never batel; the Mishnah simply gives examples of things that had that status at the time the Mishnah was formulated.  Our author explains one formulation of that category: foods so valuable that the householder counts exactly how many of each is in the pantry.  So, for example, someone hosting a party would not count the pretzels but would count the number of steaks.  And that can lead to an unexpected halachic result.  A whole animal, such as a cow, is not considered a food item a householder would count.  It is not ready to eat, so there is no immediate anticipation of pleasurable eating.  However, if the cow is slaughtered and steaks are prepared from it, the steaks would constitute something the host would count and therefore not batel.

Another formulation for items that cannot become batel are items fit to be served to honored guests.  Authorities disagree about whether this means only cooked items or also raw items. 

A note on pedagogy before we go on.  The author introduced the concept of bitul when he discussed the prohibition on cooking meat and milk together.  He brings us back to the concept here.  That might be just a coincidence; it is certainly relevant to these mitzvot.  But I think there is systematic pedagogy going on as well.  The author introduces a concept, then periodically comes back to it, forcing us to review it.  Often each new mention adds to the depth of our understanding.  By the time the project is done, we will have learned the concept well.

Mitzvah #164 prohibits our eating shratzim that swarm in the water. That includes anything that lives in the water except for fish, which were governed by mitzvot we have already seen.  The author covered some of the dinim of this mitzvah in the prior essay.

            Instead, the author goes off on a tangent, a disagreement between Rambam and Ramban on how punishments work.  The structure the author uses in each essay has already introduced us to the basic rules of punishments.  Again, he is building on a pedagogic foundation he has already laid.

            There is a familiar Rabbinic game:  How many mitzvot could a person break by doing some given action.  Here the author quotes the Gemara for a version of that game:  “If someone ate a putitha [a small water critter], the person could get four sets of malkos; if an ant, five sets of malkos; if a hornet, six sets.”  The author explains a dispute between Rambam and Ramban about how these results might come about.

            Rambam holds that for one act of breaking one mitzvah, someone gets at most one set of malkos.  In order to get more than one set of malkos, there must be some element of the action of breaking the mitzvah that is different.  (This is parallel to the way double jeopardy works in American law.)  Or there must be more than one mitzvah being broken. The issue here is not how many times a given prohibition is mentioned in the Torah, but how many separate mitzvot the Rabbis understood were expressed by the Torah.  Thus, to explain the Gemara, Rambam must understand each type of critter as prohibited because of a different mitzvah.  We saw earlier that it is hard to see those separate mitzvot in the source verses.    Rambam, according to the author, would understand the Gemara by saying that each of the different critters mentioned could be thought of as a water critter, a crawling on the earth critter, a flying critter, etc.  The person who eats one of these critters violates several different mitzvot and is thus potentially punishable several times.

            The author finds Rambam’s reading of the Gemara strained, and says Rambam himself was not entirely satisfied with it.  The author he goes on to explain how Ramban understands it.  We have seen earlier that Ramban thinks someone who breaks a given mitzvah can be punished several times for one violation.  Rather, a person who breaks one mitzvah can be punished for each time the mitzvah is reiterated in the Torah.   According to Ramban, only one mitzvah prohibits eating all the various types of critters.  He relies on Deuteronomy 14:3, supplemented by the general prohibition on “abhorrent things” in Leviticus 11:43.  Thus, only one mitzvah prohibits our eating forbidden types of mammals, birds, fish, locusts and shratzim, but that mitzvah is repeated several times.  It’s not clear how Ramban would know how many times someone would be punished for any given act.

            Look at the summary paragraph at the end of this essay.  The author adds a concept he hasn’t made quite clear until now.  We know that there are things we are prohibited to eat.  We know that a Jew who eats those foods is not punishable unless he or she eats a certain minimal amount.  Is that person permitted to eat less than that minimum amount, or forbidden to eat but just not subject to punishment?  The author clarifies.  Hatzi shiur assur min hatorah,” “Half of the minimum punishable amount is prohibited by the Torah.” 

            Also note how the author ends his description of the disagreement between Rambam and Ramban.  “Listen to them.  If you merit, you can choose between them.  Both these and those are the words of the living God.”  There is a world of pedagogy in that comment, and it’s a far cry from the parental tantrum we saw in mitzvah #16.

            Let’s assume that this comment reflects what the author considers to be a much better attitude on his son’s part.  The comment embodies the attitude the author wants his son to have toward himself.  The author projects his son into the role of “respected beginner.”  There is no veneer of self-esteem here.  The author is respectful of his son and therefore avoids false praise.  Right now, the son does not have the skills, background or maturity to decide between the opinions of great authorities.  But that need not be a permanent situation.  If the son continues to learn and to understand, he may eventually join the conversation at a higher level, as a fully qualified participant.  And that status is within reach.  That’s the author’s goal for his son and for other students of his work. 

            Note also that the author fully believes that Rambam and Ramban disagree.  The job of subsequent students is not to try to reconcile their opinions, but to master the arguments on both sides and then figure out who has the better argument.  They are not both right and later students should evaluate the arguments and make a choice.  It is clear that the author agrees with Ramban here.  (Actually, the author typically explains the Ramban’s opinion only when the author agrees with Ramban rather than Rambam.)  But, as we have seen before, the author models respectful disagreement.  Each participant in the dispute gets full respect.         

            Mitzvah #165 prohibits our eating shratzim engendered in decaying matter.  Here the author introduces the relationship between the mitzvot about shratzim and spontaneous generation, and uses this to sum up this series of mitzvot.

            The author says that we are forbidden to eat any critter engendered in decay, whether by sexual reproduction or by spontaneous generation.  But the critters are only prohibited if they swarm on the earth.  So a sheretz in decayed fruit is fine if it was formed after the fruit was picked and is still in the fruit.  Similarly, a sheretz in rancid water is fine.

            Our author describes which shratzim we are forbidden to eat and which shratzim we are permitted to eat.  It may be surprising that there are shratzim we are permitted to eat, as recent discussions of halachah would seem to imply that we are forbidden to eat all little critters and we have to search diligently through our food to make sure there are no little critters.  Although there are differences in detail, our author’s description is much closer to the description in the Rambam’s Mishneh Torah and in the Shulhan Aruch.

            We all assume that the physical world works the way our own society understands it to work.  For the rishonim, and earlier authorities, that means the belief that some animals reproduce sexually and some reproduce by spontaneous generation.   Clearly that distinction influences rabbinic authorities in how they understand what we are permitted to eat.  We no longer accept that any critters reproduce by spontaneous generation.  That leaves a difficult problem:  how do we handle halachah that was influenced by outdated science?  Here, if we say we accept whatever the halachah was formulated to be despite its being based on outdated science, or if we say that the science the rabbis used must have been right, we end up deciding that there are little critters that we are permitted to eat.  We only end up saying all critters are forbidden if we say the science the rabbis relied on is outdated.

            Note that, in general, our author does not mention any requirement that we check a given food.  (He does tell us not to pour beer through straw at night, and he tells us to check fruit that might have worms when we do not know if the worms originated before or after the fruit was picked.)  He does not require us to check any specific way.  Nor does he require that the person preparing the food do so during the day, or even that the person preparing the food has reasonably good eyesight.