Custom Made: What is the Power of the Minhag?

Stranded in the Australian outback, the small team of explorers were exhausted, hungry, and a thousand miles from home. 

Robert Burke and William Wills had led their ill-fated expedition out from Melbourne in the winter of 1860, along with nearly twenty men, a small herd of horses and camels, and a two-year supply of food. They were the first Europeans to traverse Australia’s great southern land—but sadly, the two men ended up getting stuck and dying in the middle of the continent’s vast interior.

And yet somehow, other humans managed to live comfortably in this seemingly inhospitable landscape. In fact, when they were beginning to run out of food, Burke and Wills had made brief contact with a local aboriginal tribe called the Yandruwandha, who generously stocked them up on fish, beans, and some “nardoo” cakes made from the seed-like spores of a local semiaquatic fern. Clearly, the Yandruwandha knew enough about the local flora and fauna to find or forage all the food they needed.

The nardoo cakes—basically aboriginal matzah—seemed simple enough to make. Mimicking some of the native women they had observed, the two explorers gathered the nardoo seeds, pounded them into flour, and baked them into enough cakes to fill their growling stomachs. The problem was that, unless properly processed, raw nardoo contains the toxin thiaminase, and is basically indigestible.

Traditionally the nardoo flour would be leached in water, directly exposed to ash as it was heated up, and consumed together with mussel shells. As we now know, all of these steps help break down thiaminase and prevent its harmful effects. But, unfortunately, Burke and Wills missed a few steps, so no matter how much they ate, they just kept on wasting away. 

The story of Burke and Wills is a staple of Australian folklore, a tale of heroic failure set against a harsh and terrifying landscape. But Harvard biologist Joe Henrich puts the story—along with the stories of other ill-fated British, Spanish, and Portuguese explorers—to slightly different effect in his book The Secret of Our Success. To Henrich these stories point to the limits of individual human ability, intelligence, and endurance. Although these explorers may well have been smart, resourceful, and brave men, their ability to survive in a strange land depended entirely on whether they were able to learn from the other humans who were already living there. 

These stories, along with Henrich’s discussion, carried a strange resonance for me. Imagining those Yandruwandha women pounding nardoo seeds, soaking them in water, and mixing them with ash, faithfully following a process handed down from the early mists of prehistory, made me think of some of our own traditions: grinding maror, pounding willow branches, mixing charoset, folding hamantaschen, baking challah, and so many other Jewish traditions handed down to us through the generations.

And maybe the comparison isn’t as odd as it first appears. Not unlike us Jews, mutatis mutandis, pre-contact indigenous Australians maintained a remarkably conservative culture over thousands of years. Who knows how long they had been painstakingly processing that nardoo, without ever having heard, we can safely surmise, of thiaminase or knowing how it gets broken down? What kind of unknown power might our own customs possess, with their occasionally obscure origins and mysterious details?

Just a Custom?

But first, a step back. In Jewish law, one might say that there are three levels of authority; that is, three possible sources for any given practice. There are laws derived directly from scripture (“d’oraita”); these are the 613 commandments, along with all of their various components and subdivisions, from eating matzah at the Seder to the prohibition against  cooking on Shabbat. Then there are laws legislated by rabbinic authority (“d’rabbanan”), from the entire festival of Purim to lighting candles before Shabbat. And then there are the minhagim—customs. 

Of these, the category of the custom is the most amorphous. It covers everything from the preferred garb of a given Chasidic group, to the slow-cooked cholent served for Shabbat lunch, to the particular rite with which one chooses to pray. It includes practices and restrictions that have come to carry the mandatory force of Jewish law—like the evening prayer for men, or the Ashkenazic prohibition against eating rice on Passover—as well as many other customs that remain voluntary or allow for considerable variation between communities, like the kind of hat you wear on Shabbat, or the lullaby you sing to put your children to sleep. 

And more than merely amorphous, minhagim are mysterious too. To be sure, the fact that a lot of Jewish people do something––say, enjoy their bagels with a bit of lox––is not enough to turn a popular practice into a legitimate minhag. Rather, a genuine minhag must bear some kind of religious meaning, and will invariably carry the endorsement of traditional spiritual authorities. 

And yet, unlike any kind of scriptural or rabbinic law observed today, a minhag does not need a textual source. In fact, it is often the case that the origins and reasons behind a particular custom are shrouded in obscurity. A subgenre of literature has sprung up to explain the existence of specific customs, first presenting minhagim and then reverse-engineering their sources. And even where those sources elude us, failing to discover the rationale behind a genuine minhag is no reason to discard it. As an extraordinary statement by the great medieval sage Rabbi Shlomo ibn Aderet (1235–1310), the RaSHBA, has it: “A custom of the grandmothers of Israel [read: Jewish bubbies] may not be cancelled, even with 600,000 reasons to the contrary.” 

More than that, one would think that the biblical or rabbinic laws, laid down to us at Sinai or by the sages of the Sanhedrin, would be more important or carry more weight than matters of minhag. And yet somehow we find that it is precisely those areas of Jewish practice which are based on mere traditions that attract the greatest devotion—sometimes, as some have argued, too much devotion. 

So if minhagim are just customs, why do people take them so seriously? 

A Question on the Four Questions

In a 1957 talk, the Lubavitcher Rebbe points us in the direction of an answer. The Rebbe wonders about the order of the Four Questions asked on the Seder night, and specifically about the first question: “Why is this night different from all other nights? On all nights, we do not dip [our food], but on this night we dip twice, first in saltwater and then in charoset.” 

Putting the question about “dipping” before any other seems a little odd. Dipping the vegetable into saltwater isn’t the first unusual thing we do at the Seder—that would be the way we recline while drinking wine at Kiddush (the fourth question). Nor would it seem to be the most serious mitzvah of the night; surely that would be the matzah (second), which the Bible commands us to eat, whereas “dipping” is mere minhag.

Instead, the Rebbe suggests that the question on dipping comes first precisely because it is minhag:

There are those who say that a biblical commandment must be fulfilled with utter commitment, even to the point of sacrifice… but customs—if they come easily, then of course, but one need not make any sacrifices for them…

The order of the questions tells us that… the first thing a child notices, and which makes an impression is… a Jewish custom. That is what catches his eye, and has the greatest effect on him. (Likutei Sichot, vol. 1, pp. 244)

In so many ways, as the Rebbe goes on to say, the things that make Jewish life distinctive, that sets it apart from the surrounding culture, that make up the warp and weft of the Torah lifestyle, are so often minhagim. The formal obligations derived from the Torah, the Talmud, and the Code of Jewish Law are one thing, but to form a firm sense of Jewish identity, one needs an authentic, organic, lived Jewish culture, which is in turn defined by the minhag—the way we dress, the names we call each other, the food we eat, the songs we sing at the Shabbat table, and so on and so on.

If a child’s lifestyle and environment are similar to that of his non-Jewish surroundings—even if he regularly studies Torah, prays, keeps the mitzvot, and so on—since he [otherwise] acts in the same way as his surroundings, then it will not be apparent that he is a Jew. (Ibid.)

The sixth Lubavitcher Rebbe spoke up the minhag in similar tones:

In the previous generation, Jewish people knew well the concept of [the minhag], and kept them meticulously… They knew that, aside from the fact that Jewish customs are founded in holiness, and that they themselves are Torah, Jewish customs are the splendor of the Jewish people… (Sefer HaSichos 5700, p. 43) 

But all of this is not quite enough to understand the reverence with which Jewish customs are held. In the classic formulation, a “minhag of the Jewish people is itself Torah” (see Tosafot on Talmud, Menachot 20b). It’s one thing to speak about the role of custom and culture in forming Jewish identity, but to say that a custom is part of the holy Torah, with all that entails, is quite another thing.

Again, a comparison between the three categories we began with is instructive. It doesn’t take much to appreciate why the biblical commandments are so important: G-d told us at Sinai to follow the commandments, and you can’t get any better than that. The Torah in turn tells us to respect the authority of the rabbis, whose expertise and spiritual attunement grant them the power to legislate and determine Jewish law. But a custom is, fundamentally, simply something that Jewish people do. What elevates it to the status of Torah? Without explicit revelation or rabbinic authority, where does the power of the minhag come from? 

For that, let’s return – much like, one feels compelled to say, a boomerang arcing its way across the sky – back to the Yandruwandha women. 

The Collective Brain

The lesson that author Joe Henrich draws from his tales of lost European explorers is one that he applies to the entire history of our species: the extraordinary success of human civilization depends less on raw individual intelligence than on our ability to accumulate and share knowledge at the group level. To put it simply, groups are smarter than individuals.

This may seem like a counterintuitive claim. The unwashed masses, the braying crowd, and mob rule never have had a good reputation. But as the writer James Surowiecki explores at length in his Wisdom of Crowds, while it is true that conformism and groupthink can lead people astray, groups are generally smarter and more knowledgeable, and better at predicting the future, solving problems, and much else.

At any rate, the simple fact is that there are hard limits on how much a person can figure out on their own. Think of poor Robert Burke, trying to get the nardoo preparation process right. Or think about how much we rely on the accumulated expertise of others every single day. A fun thought experiment to illustrate this is to imagine how many modern amenities you would be able to recreate if you were suddenly transported back to, say, the Bronze Age. Granted unlimited resources and manpower, how would you go about making an iPhone? Building an internal combustion engine? Producing antibiotics? Synthesizing fertilizer?

Now of course, I wouldn’t have the first clue how to do any of these things, but we do. In fact, nobody knows how to do every one of these things, and yet somehow we manage to do them every day. But what is this “we” exactly? 

To understand the way a given population holds on to and transmits its technical knowledge and cultural traditions, Henrich refers to their “collective brain,” knowledge that is not housed in any one brain, a large library, or even a data center; instead it emerges from a group of individuals capable of transmitting information, as a function of the size and interconnectedness of that society. 

If we turn all this to our own purposes, and make the leap from the sociological to the theological, the “collective brain” is strikingly reminiscent of an idea that can be traced back to the foundational texts of halachah. To take one example from the Jerusalem Talmud:

Any halachah about which there is some uncertainty in the courts, and you do not know what its status is, go out and see how the community is accustomed to act—and then act like them. (Jerusalem Talmud, Ma’aser Sheni 5:2)

This piece of jurisprudential advice—a testament to the power of custom—is repeated numerous times throughout the Talmud: go out and see what the people are doing. Again, considering that the Talmud is essentially a record of the intramural debates of a small circle of scholarly elites, this is exceedingly odd: If the rabbis who have devoted their lives to studying the Torah and preserving the traditions of the Oral Law can’t figure out what the law is, why would the people do any better? What do the masses have that the rabbis don’t? 

Another passage, this time from the Babylonian Talmud, makes explicit the extraordinary rationale behind this principle. The Talmud is discussing the laws of the paschal lamb, the sacrificial offering that families brought to the Jerusalem Temple on the eve of every Passover. One year, the day before Passover happened to be a Shabbat. The sacrifice would still be performed in the usual manner, but a question was asked of the great sage Hillel: What if someone forgets to bring the knife they need to perform the offering at the Temple Mount? Normally, one may not carry anything on Shabbat—does that law still apply? To this Hillel replies:

I heard this halachah [from my teachers], but I have forgotten it. But leave it to the Jewish people; if they are not prophets, then they are the sons of prophets. (Talmud, Pesachim 66a)

That Shabbat, Hillel went out to see what the people were doing. Lo and behold, they had come up with a creative workaround to avoid violating the prohibition against carrying on the holy day: They made their animals carry the knives instead!

The next day, one whose paschal offering was a lamb stuck [the knife] in its wool; one whose paschal offering was a goat stuck it between its horns. [Hillel] saw the incident, remembered the halachah, and said: “This what I received from the mouths of [my teachers]…”

This remarkable story answers our previous question. The way some commentators have it, the reason the rabbis of the Talmud were able to defer to the halachic authority of the common folk was because those common folk are “the sons of prophets.” That is to say that the Jewish people possess quasi-prophetic powers, a kind of halachic sixth sense, that helps them intuit the way G-d wants them to fulfill the Torah’s commandments. Think of Henrich’s “collective brain,” only supercharged, spiritualized, and directed towards the observance of Jewish law. 

In fact, the 18th-century Lithuanian rabbi and kabbalist Rabbi Eliyahu Ragoler explicitly refers to this intuition as ruach hakodesh, the “holy spirit” of spiritual perception typically only associated with the most pious and righteous leaders and sages:

…When a custom has become consensus within the Jewish people, it is a result of ruach hakodesh, whereby G-d has revealed Himself among them, just as He would guide a prophet. For when their will and their actions are directed for the sake of Heaven, G-d illuminates for the Assembly of Israel, with ruach hakodesh, the right way to act. There is proof for this idea from [the Talmud]: “If they are not prophets, then they are the sons of prophets.” (Yad Eliyahu, Pesakim, sec. 25)

A Custom as a Kiss

We have traveled a long way from pounding nardoo down under with the Yandruwandha. But the same concept that explains how a tribe of hunter-gatherers (or indeed, any human society) is able to access a body of transgenerational wisdom acquired organically, can, by way of analogy, also help us appreciate our own people’s ability to tap into a transcendent divine intelligence – through the popular practice of halacha, and in particular in the form of the minhag.

Previously we divided the sources of Jewish religious practice into three general categories: biblical law, rabbinic law, and customary law (minhag). By now we can better appreciate how all three are a part of the Torah; as the Chasidic tradition goes, even minhagim were given at Sinai, and were simply revealed later.

Typically, and reasonably enough, it is assumed that biblical law—those 613 mitzvot revealed to us straight from Sinai—is the most “important” of the three. But the truth isn’t quite as simple as that. 

The minhag is an expression of ruach hakodesh—of the Divine will—not simply as it manifests in the Talmudic debates of the rabbis and the study halls of the scholarly elite, but as it manifests in the timeworn traditions of an entire people, in the collective hearts and minds of the Jewish nation. 

The words of the Torah are G-d’s explicit communication with the Jewish people. But words can say only so much; our truest feelings, our deepest desires, our strongest passions, are hardest to articulate. Sometimes the things we leave unsaid mean the most, the implicit is more powerful than the explicit, the subtext deeper than text. 

The Chasidic masters teach us that the same is true of G-d. The messages He did not put explicitly in the Torah—the implications He left for us to figure out, the laws and customs He left to our own discretion—are in some sense the deepest message of all. 

It is true that the customs of Judaism, the minhagim, are not recorded in the Five Books of Moses. It is true that a good many minhagim carry neither obligation nor prohibition, nor any penalty for our failure to fulfill them. Instead G-d leaves them to us, and that is their power. 

“When a father loves his son,” the Rebbe once offered by way of analogy, “he provides for his necessities (that is, things which are d’oraita); when the love is more powerful, he gives toys or other luxuries (d’rabbanan things); but when his deepest love is revealed, it cannot be expressed by any of these things, but only by hugging or kissing him.” (Toras Menachem, vol. 24, p. 128)

A minhag as a hug. That is, the customs and traditions that define the familiar contours of Jewish practice, filling it with so much color and life, are that unspoken kind of affection: They are G-d’s will, unstated but revealed within a nation of prophets, an expression of the love between G-d and His people, freely reciprocated. This is the power of the minhag.

This article appears in the Spring/Summer 2025 issue of Lubavitch International, to subscribe to the magazine, click here.