This week’s Torah portion, Shemini, presents the laws of kashrut for animals, fish, birds, and locusts and describes their signs. Kosher land animals chew the cud and have split hooves; kosher fish have fins and scales. For birds, the Torah lists forbidden species, while later the Sages identify bio-physical signs of a kosher bird including it not being a predator and having a goiter.
One striking feature is that although these are food prohibitions, the Torah often phrases them positively: “These are the animals you may eat”; “These you may eat from all that are in the waters”; and similarly in Deuteronomy. Commentators noted that there is no separate positive commandment to eat meat, fish, or fowl. They therefore understood this language as adding another negative command: that one who ate from non-kosher foods also transgressed by not eating permitted kinds.
Maimonides, in Guide for the Perplexed (III:48), explains that the dietary laws train a person to distance himself from what is base and to prevent addictions to one’s desires. Maimonides adds that the signs of kashrut are not the cause of permission and prohibition, but markers by which we distinguish better kinds from inferior ones. However, in three other places Maimonides goes further and expands and emphasizes the positive side of the commandment.
In Sefer HaMitzvot he counts four separate positive commandments: to examine the signs of animals, birds, locusts, and fish. Regarding birds, since the Torah does not spell out signs, he says they are inferred through investigation. Regarding fish, he writes that the commandment is not only to inspect, but to categorize by these signs and say: “This may be eaten and this may not”. Sefer HaChinukh adds that even if someone happened to eat kosher food without proper examination, he still failed to fulfill the positive command to check. Ramban disagrees and argues that this duty should not be counted separately, since it only serves the food prohibitions.
In Mishneh Torah, Maimonides develops the idea further. In the headings to the laws of forbidden foods he speaks not only of examination but of distinction: “to check the signs, to distinguish between the impure and the pure”. Then, in the laws themselves, he broadens it further: “It is a positive commandment to know the signs by which one distinguishes between animals, birds, fish, and locusts that may be eaten and those that may not”.
Commentators asked whether examination and knowledge are identical, what their source is, and how they relate to the verses about distinction. Rabbi Asher Weiss suggested that examining refers to the food before you, while knowing refers to recognizing, at the level of species, which creatures are kosher and which are not.
Building on Maimonides, the Rogatchover Gaon suggests that one may distinguish between a sign that merely identifies and a sign that actually defines status. On this view, the signs of mammals and fish are status-conferring, while the signs of birds and wild animals mainly prevent error.
I would suggest based on Maimonides that the laws of forbidden foods are meant to make us concretely aware of the knowledge embedded in the natural world. For Maimonides, kashrut is not merely abstention from prohibited foods. It builds understanding: to know the signs, reason from them, investigate shared traits, and classify each creature not only as permitted or forbidden but according to its nature.
When the Torah commands us “to distinguish between the impure and the pure”, it calls for attention to the mystery of life itself. To reach the root of the edible creature’s qualities, and to ask what differs in the creature that may not be eaten, is in some sense to understand the nature of life, of goodness and of “Godness”.
The better we understand biology, with all its wonders, the better we understand the Creator. As Maimonides writes in Hilkhot Yesodei HaTorah, love and awe of God arise when a person knows and contemplates His wondrous creations and sees in them boundless wisdom. Yet knowledge does not remain knowledge alone. It leads to action. In Guide for the Perplexed (III:54), the highest knowledge of God gives birth to moral life: lovingkindness, righteousness, and justice.
Today, in the age of artificial intelligence, even if we reach superintelligence, silicon minds will not truly stand in wonder before creation, nor likely create new living beings. AI can, however, become a powerful tool for understanding creation more deeply. We should use it to investigate the world and create new things. In fact, speech, the hallmark of the human being according to Onkelos, that shapes society, law, leadership, and culture still truly belongs only to human beings endowed with care and moral involvement.