Throughout the ages, despite differences in culture and cuisine, Jewish kitchens around the world shared a commitment to kashrut—the classical rules regulating the Jewish diet. This religious lifestyle, known as “keeping kosher,” which is still observed in a great many Jewish homes today, encompasses a number of restrictions. Traditional Jews keep all meat and milk products separate; meat is salted before cooking; and animals must be ritually slaughtered before they may be eaten. But perhaps the most famous restrictions, and the ones most explicit in the Bible, are those laid out in Leviticus, which limit the kinds of animals that a Jew is allowed to eat. By eating only certain animals and not others, Jews all over the world have adhered to “the Tora of the beasts, and of the birds, and of every living creature that moves in the waters, and of every creature that creeps on the earth: To make a distinction between the unclean and the clean, and between the beast that may be eaten and the beast that may not be eaten.”1
As unified as traditional Jews have been, however, in adhering to the Tora’s dietary distinctions between permitted and forbidden creatures, they were equally as diverse in explaining the meaning of kashrut, offering over the centuries a wide array of explanations. This is due in large part to the fact that the Bible itself, in distinguishing between permitted and forbidden animals, gives no explicit explanation for the rules; rather, Leviticus 11 offers fairly opaque criteria for determining “pure” and “impure” creatures. This sense of mystery is itself compounded by the fact that different distinctions are made among different sorts of species. For example, when it comes to quadrupeds, we are informed that only an animal “with clefts through the hoofs, and that chews the cud—such you may eat.”2 Jews, then, are permitted to partake of domesticated animals (beheimot) such as the cow, goat, or lamb, as well as of “wilder” species (hayot) such as the deer and the antelope, but are enjoined not to eat of the pig, camel, hare, or rock badger, which lack one of the two required signs, or of the horse, bear, or rhinoceros, which lack both. In the case of fish, the Bible permits only those with both fins and scales.3 Species of marine life lacking one of the two, such as the shark or catfish (which have no scales), or both, such as shellfish, are forbidden. The Bible takes another mysterious turn in its discussion of birds, giving no instructions for the determinations of permitted fowl at all, but instead merely listing those that are forbidden. “The following, ”Leviticus declares, “you shall abominate among the birds,”4 going on to list the eagle, the falcon, the vulture, and the owl, among others. Whereas the Sages of the Talmud and other commentators suggest that all the forbidden birds are predators, the Bible never says this explicitly. The reader of the Bible is thus presented with a compendium of rules for kashrut determination, without any immediate explanation for them.
While the rules pertaining to “the beasts, the birds, and every living creature that moves in the waters” are familiar to every kosher-keeping Jew, it is often forgotten that the dietary prohibitions pertain to the world of insects, as well, and that the distinctions made among permitted and forbidden bugs are perhaps the most mysterious of all. The Bible does not, on the whole, appear to deem insects worthy of Jewish consumption; we are told that “all winged swarming creatures that walk on all fours shall be an abomination to you,”5 forever forbidding the bee and the butterfly as objects of Jewish culinary delight. We are later told that all insects that cannot fly are forbidden as well: “All creatures that swarm upon the earth are an abomination.”6 Thus, the Bible explains, Jews are forbidden to ingest “anything that crawls on its belly, or anything that walks on all fours, or anything that has many legs,”7 referring respectively to creatures such as the worm, the ant, and the centipede. In Deuteronomy, where the laws of kashrut are reiterated, no mention is made of any exceptions to this last prohibition; yet, in the midst of the discussion in Leviticus, the Bible explicitly permits those insects that neither walk nor fly, but leap: “But these you may eat among all the winged swarming creatures that walk on all fours: All that have, above their feet, jointed legs to leap with on the ground.”8 The permitted insects, then, are “locusts of every variety, all varieties of bald locust, crickets of every variety, and all varieties of grasshopper.”9 Once again, however, no explanation is given for why these insects are allowed, and why they prove the exception to the general biblical ban on eating insect life.
The laws of kashrut, in other words, while having had an important impact on the life of the Jewish people, have never really been understood; no clear explanation has ever been given for why one may eat of the cow but not the camel, of the carp but not the catfish, of the turtle-dove but not the turtle. In what follows, I will suggest that perhaps the Bible does not elaborate on why these distinctions are made because it is less interested in our understanding God’s reasons for choosing these specific criteria than it is in our comprehending the larger importance of making such distinctions among all forms of life. Indeed, the careful reader of the Bible and its rabbinic interpretations will see that later on in Leviticus, the Bible does make it quite clear why keeping kosher is important—and why the Jewish dietary rules continue to remain relevant today.
II
To understand what kashrut really is about, it is important first to understand the problems associated with some of the explanations offered for it in the past. Among the great medieval Jewish philosophers, one explanation of kashrut was particularly popular: The Bible, it was often claimed, forbade the ingestion of all animals that are injurious to one’s health. This explanation was offered, for example, by two of the greatest of medieval rabbinic figures: Maimonides, who lived in Alexandria in the twelfth century, and Nahmanides, who lived in Spain in the thirteenth. Both were physicians who wrote extensively not only on Jewish law and philosophy, but on medicine as well. In his Guide of the Perplexed, Maimonides, arguing that there exists a rational explanation for all Mosaic laws, insists that biblically forbidden foods are obviously unhealthy:
I say, then, that to eat any of the various kinds of food that the Law has forbidden us is blameworthy. Among all those forbidden to us, only pork and fat may be imagined not to be harmful. But this is not so, for pork is more humid than is proper and contains much superfluous matter. The major reason why the Law abhors it is its being very dirty and feeding on dirty things. You know to what extent the Law insists upon the need to remove filth out of sight, even in the field and in a military camp, and all the more within cities. Now if swine were used for food, marketplaces and even houses would have been dirtier than latrines, as may be seen at present in the country of the Franks.10
Nahmanides, in his commentary on the Five Books of Moses, notes that the biblical dietary restrictions result in the exclusion of all predators from Jewish cuisine, and insists that science lends insight into the Bible’s ultimate intent. “Every bird of prey,” he writes, is unfit for human consumption, “because its blood becomes heated due to its cruelty, and is dark and thick, which gives rise to that bitter [fluid in the body] which is mostly black and tends to make the heart cruel.”11 Nahmanides further notes that “it is possible that the reason for certain animals [being forbidden] is similar, since no animal that chews the cud and has a parted hoof is a beast of prey.” As for forbidden fish, he argues that those without both fins and scales “always dwell in the lower turbid waters… hence they are creatures of cold fluid, which cleaves to them and is therefore more easily able to cause death.”12 (Strikingly, neither Maimonides nor Nahmanides offers an explanation for why, among all insects, only the locusts and grasshoppers are permitted.) Similarly, the anonymously authored Sefer Hahinuch, an important medieval enumeration and explication of the commandments, draws on both Maimonides and Nahmanides in arguing that with regard to the dietary laws, “it was therefore the great kindness of God toward us, his people whom he chose, to remove us from every food that is injurious to the body.... This is the rule to which I hold, according to the plain meaning, in every ban imposed on food, as we stated above.”13
This medical approach to the Bible, so popular in the medieval period, was subjected to a withering and, in my opinion, convincing critique by the great Spanish Jewish exegete Don Isaac Abravanel. “Many have already thought,” Abravanel writes in his commentary on Leviticus, “that the prohibition placed by the Tora on forbidden foods is because of the health of the body and its healing, that the wrong foods lead to the development of hurtful fluids; and this is the opinion of Nahmanides.”14 The problem with this approach, he argues, is threefold. First, it turns the Bible into a medical textbook, one more concerned with cleanliness than godliness, and “this is not the way of the Law of God, nor its ultimate intent.”15 Second, Abravanel argues that Nahmanides’ account is empirically false: The Gentile nations, who have been eating foods that are purportedly noxious to their long-term health, are, if anything, healthier than most kosher-keeping Jews. “We see before our eyes,” he wrote, “that the nations that eat the flesh of the abominable swine and the rodent and other birds and animals and forbidden fish are all living today in a state of strength, and there is not a tired or weak man among them.”16 Third, he concludes, if the Tora was truly concerned with regulating our diet out of health concerns, why did it not prohibit the eating of harmful vegetation? In sum, the medical explanation of kashrut, as time-honored as it may be, is difficult to accept.