1. Jewish identity is such that you’re either “Jewish by birth” or “Jewish by choice.” The former is traditionally matrilineal: If your mother is Jewish, then you’re Jewish. You’re a born Jew. But some especially liberal sects of modern Judaism make an exception: Even if your mother isn’t Jewish, you’re Jewish as long as (a) your father is Jewish and (b) he raised you Jewish.
2. The traditional or prototypical Jew is a Jew born and raised: His father is Jewish, his mother is Jewish, and he’s raised Jewish and only Jewish. But there are plenty of variations: (a) There are people born Jewish but not raised Jewish. (b) There’s also the opposite: people raised Jewish but not born Jewish. Those are the aforementioned Jewish-father-raised, Jewish-motherless people accepted as Jewish in the especially liberal sects. (c) There are even Jews who were neither born nor raised Jewish. Those are the converts.
3. The converts. Conversion is akin to adoption. You’re “adopted” into the Jewish “extended family.” There are two problems with conversion: (a) It’s rare for people to truly internalize and bring into themselves at the deepest level a culture that they didn’t grow up with. And (b) you can convert to Judaism, yes, but you can’t convert your blood to, say, Ashkenazi blood. The Jews have been incredibly successful in religion, business, philosophy, and science, but thinking that converting to Judaism would give somebody without any Jewish blood the advantages of being Jewish would be akin to thinking that giving up a black baby for adoption to a rich white family would give the black baby the advantages of being white. Of course that would only give one side: the white-cultural advantages. Any white-biological advantages would stay closed to the child. And that analogy is about adoption at birth. Adoption as an adult is even less likely to give any kind of privilege or advantage. Imagine a 30-year-old black man who was raised in a poor black neighborhood being suddenly adopted into a rich white family. He may learn something, sure, and he may teach his adoptive family something as well. But ultimately adults just don’t change very much.
4. The Jews are by and large an extremely stubborn people because the modern-day Jews descend from countless generations of people who refused to convert to Christianity despite Jewish persecution. The Jews who converted out took their blood with them.
5. Anybody can say that they’re Jewish in the same way that anybody can say that they’re a native speaker of, say, Japanese. That’s because anybody of any race could conceivably be Jewish and anybody of any race could conceivably be a native speaker of Japanese (or of course of any language). There’s no way to disqualify somebody of either of those qualities by appearance only. There’s nevertheless prejudice or strong association with appearance: Some appearances (e.g., racially Japanese-passing, which is a subset of Northeast Asian) are rare among Jews in the same way that some appearances (e.g., white, black) are rare among native speakers of Japanese.
6. By contrast, it’s not the case that anybody can say that they’re, say, Northeast Asian, white, or black. Race isn’t something that you can convert into or learn. It’s set in stone at birth.

The Jews have been blamed not only for being greedy and exploitative capitalists, but also for being radical socialists and communists. There are many other examples of that kind: The Jews have been criticized for being too rich (e.g., in Western Europe in the 19th century), and they’ve been criticized for being too poor (e.g., in Eastern Europe at that time).  They’ve been criticized for assimilating, and they’ve been criticized for not assimilating. They’ve been criticized for not having a state (before the founding of modern Israel), and they’ve been criticized for having a state (after the founding of modern Israel). Etc.

Antisemitism, which has kept itself relevant for millennia, is the ultimate shapeshifter. It cynically and opportunistically flip-flops its arguments in order to justify anti-Jewish sentiment no matter what.

Well, at least that’s the popular understanding in the 21st century. However, on capitalism and socialism: It’s actually not so much of a contradiction that the Jews have been strongly associated with the excesses of both capitalism and socialism. After all, many of the most influential of the early socialists were Jews born into rich families. They saw that much of the antisemitism around them was about the Jews as evil capitalists, and their reaction, tragically, was to turn that onto its head: They became socialists, which was in effect an apology for the evil capitalism of their fathers. The Jews had long been on the cutting edge of money and the market. They contributed in a major way to the evolution of capitalism in Europe. For that, the Gentiles should have been appreciative. After all, capitalism brought unprecedented wealth (not only to the upper strata of society, except perhaps temporarily, but to every strata of society). And of course some Gentiles were appreciative. But enough weren’t, and in the late 19th and early 20th centuries many assimilated Jews, again tragically, took to heart the anticapitalist, antisemitic arguments of their Gentile peers.

Karl Marx (1818-1883) is the quintessential example. Despite being Jewish himself—well, despite being a born Jew, which contrasts with his childhood baptism—he was extremely antisemitic. He saw the Jews as the scourge of Europe. To Marx, the Jews were “capitalists” in the worst sense of the term: shamelessly greedy and exploitative.

For centuries, the Jews had been on the cutting edge in the practice of capitalism, which was a great contribution to Europe (at least in the long term). And then suddenly, the Jews were on the cutting edge in socialist theory, which threatened to undo (and eventually did temporarily undo, with untold tragedy as the result) the misunderstood capitalist contributions of their people. Thus: There’s no mystery in why the Jews are popularly associated, at first glance in an inconsistent/contradictory way, with that pair of opposites: capitalism and socialism.

1. Karl Marx (1818-1883) was a “self-hating Jew” in that he was a Jew who thought of the Jews as having used capitalism to take advantage of European civilization. He was a repentant Jew.
2. Tangentially: The term “self-hating Jew” is confusing because it hides the distinction between the individual and the group. It’s possible for a Jew to “love” themselves as an individual but “hate” their group. Marx may have had as much confidence in how good he was (as an individual) as he had in how evil they were (as a group that he didn’t identify with). In fact, that brings me to another distinction that the term “self-hating Jew” hides: that between identifying as (which is what the individual does) and being identified as (which is what’s done to the individual). Marx didn’t identify as Jewish—his father converted to Christianity before he was born, he was baptized into the Lutheran Church as a child, and he “converted” to atheism as an adult—and thus he probably didn’t think of his criticism of the Jews as being about himself. That’s despite the fact that in history, he’s identified as Jewish. That is: Marx was a Jew who hated the Jews, but he didn’t think of himself as a Jew.
3. The Jews of the late 19th and early 20th centuries reacted in various ways to increasing anti-Jewish sentiment: socialism, Zionism, etc. Socialism was tempting because much of the anti-Jewish sentiment at the time was ultimately anti-capitalist sentiment. The Gentiles thought of the Jews as greedy and exploitative. Socialism was a way of apologizing for that. It was a way of saying: “Yes, we Jews took advantage of the market. But we’ll get rid of the market, which is a vice, and then we’ll never be able to do that again! Indeed, nobody will ever be able to do that again.”
4. It’s a sad story because (a) socialism is absurd in theory and catastrophic in practice and (b) capitalism is nothing to apologize for.

1. If a Christian rejects Christianity, then he’s no longer Christian. But it’s different for the Jews. Some Jews go so far as to hate Judaism, but that doesn’t make them any less Jewish. A born Jew is inescapably Jewish. Consider Sigmund Freud: He had little respect for Judaism, but he had a lot of pride as a Jew, which led him to Zionism. He was part of the trend that started in the 19th century of making Jewish identity less about being a believing, practicing Jew, which is how Jews have traditionally identified with each other, and more about identifying with each other like any other national group.
2. There are strong biological patterns in the Jews. For example, the Ashkenazi Jews were so endogamous for so long that they’ve become biologically distinct. The Ashkenazi bloodline is unique. But it’s not the biology that makes the Jew. It’s possible for two people to have the same amount of Ashkenazi blood but for one of them to be Jewish and the other not.
3. The Jews are neither strictly an ethnoreligious group (for having a Jewish identity doesn’t necessarily mean being religious or making Judaism part of your identity) nor strictly an ethnonationalist group (for having a Jewish identity doesn’t necessarily mean being nationalist or making Israel part of your identity). There’s also nothing biological or racial that distinguishes every Jew from every non-Jew. There are “white” Jews, “black” Jews, etc. There are Ashkenazi Jews (with some European blood of one kind), Sephardic Jews (with some European blood of another kind), etc. Most Jews descend in part from the Ancient Israelites, but there are some exceptions: the converts with no Jewish ancestors. Etc etc. So what kind of group are the Jews? They’re a quasi-ethnoreligious, quasi-ethnonationalist group with strong biological/racial patterns. There are (1) believing, practicing Jews, (2) Zionist Jews, (3) believing, practicing Zionist Jews, and (4) Jews who want nothing to do with Judaism, Zionism, or anything else Jewish. There are the Jews who were born into the Jewish extended family, and there are the Jews who were “adopted” into the Jewish extended family: the converts. Etc.

Technically speaking, the term “ethnicity” is defined as a group of individuals who identify with each other on the basis of any shared aspect (e.g., language, culture, religion, race). That’s the standard definition in anthropology and other fields. But most people, scientists and laymen alike, at least associate the term “ethnicity” with biology, despite its technical definition not necessitating that. All in all, the term “ethnicity” means a group of individuals who (1) identify with each other because of any shared aspect—that’s the technical definition—and (2) probably share ancestry.

The term “ethnicity” is perfect for the Jews because (1) the Jews have traditionally identified with each other on the basis of shared religion—that’s true no matter how technical you want to be—and (2) the Jews by and large share blood from the Ancient Israelites, with some exceptions, and thus the association with biology/ancestry isn’t far off the mark.

However, Jewish ethnic identity is in transition. The Jews are traditionally an ethnic group whose most fundamental distinguishing criterion is religious: the Torah. But in modernity, ethnoreligion is giving way to ethnonationalism. There are countless Jews who identify strongly with their Jewishness while rejecting Judaism and accepting Zionism. The Enlightenment push for secularization has resulted in a partial replacement of the religious criteria of old with the national criteria of new. Judaism and Zionism cooperate and compete with each other for modern Jewish identity. That’s part of why the question of Jewish identity comes up so often. Jewish identity is a confusing mixture of the old and the new: of the religious and the national.

1. Converting into Judaism makes you a Jew, but converting out of Judaism doesn’t make you a non-Jew. In fact, Judaism is such that conversion into is possible but conversion out of is not. That is: Believing in and practicing Judaism (as long as you have a rabbi giving his consent and working with you) makes you Jewish, but not believing in or practicing doesn’t take that away from you.
2. The Jews are an “ethnoreligious” people in that the “ethnicity” and the “religion” go hand in hand. They move together. By contrast: Most Italians are Catholic, but converting to Catholicism doesn’t make you Italian. Catholicism is the religion of more than one people. That is: Unlike the strong or even inseparable connection between Jewish ethnic identity and Jewish religious identity, the connection between being (ethnically) Italian and being (religiously) Catholic isn’t so strong. But there’s something missing in my description of Jewish ethnoreligious identity so far: There’s the distinction between (a) whether a given individual identifies as part of a given group, e.g. whether a given individual identifies as “Jewish,” and (b) whether a given individual is identified as part of a given group, e.g. whether a given individual is identified as “Jewish.” A Jew by birth can stop identifying as “Jewish,” but that doesn’t mean that the Jews won’t keep thinking of him as a prospective proselyte. The Jews (along with everybody else) will keep thinking of him as “Jewish.” Thus, the connection (between Jewish ethnic identity and Jewish religious identity) is strong/inseparable only on the level of the group (and even then only traditionally): The ethnically Jewish are (traditionally) expected to be religiously Jewish.
3. Zionism, which is Jewish national identity (albeit an identity also open to non-Jews in that, say, “Christian Zionist” isn’t a contradiction), has to some extent replaced Judaism, which is Jewish religious identity. Nowadays it’s not as much that the ethnically Jewish are expected to be religiously Jewish (and not proselytize outside of the family). It’s more that the ethnically Jewish are expected to be nationalistically Jewish (and proselytize outside of the family).
4. Judaism isn’t a non-proselytizing religion, but a non-indiscriminately-proselytizing religion. Jewish outreach extends only as far as the Jewish extended family. Judaism wants born Jews to be believing, practicing Jews.
5. Consider the proposition: “Jews should get Jews to be Jews.” That proposition equivocates in a socially useful way. With the logic made explicit: “Believing, practicing Jews (or at least Jews who identify as Jewish, whether through Judaism, Zionism, or anything else) should get born Jews to be believing, practicing Jews (or at least identify as Jewish in one way or another).”

1. Ethnoreligious group. An “ethnoreligious group” is an ethnicity with religion as its distinguishing criterion. It’s a group of individuals who identify with each other primarily because of their shared religion (which is one of the possible ethnic distinguishing criteria) and secondarily because of, say, their shared language, culture, and race (which are some of the other possible ethnic distinguishing criteria). In turn, an “ethnicity” is a group of individuals who identify with each other for any reason (whether religious, linguistic, cultural, racial, or any other reason). For example, the Jews are an ethnoreligious group in that they identify with each other primarily on the basis of religion, with everything else being secondary.
2. It’s important to distinguish between (a) identifying with each other and (b) being identified with each other. The Jews identify with each other, but they’re also identified with each other. Jewish “self-identity” is such that the matrilineality principle dominates: If your father is Jewish, then you’re not necessarily Jewish. But if your mother is Jewish, then you are necessarily Jewish. However, Jewish “other-identity,” especially as it was during the Nazi era, is such that it’s not matrilineality but blood that matters: You can be Jewish, half-Jewish, quarter-Jewish, etc. That’s not the non-racial categorization scheme of Judaism, but the racial categorization scheme of something non-Judaic.
3. Connotation and denotation, intension and extension. The Jews have long been such that they “define”—here I should actually use the term “connote,” for that gets at exactly what I mean—themselves as the group of individuals who are either Jewish by choice or by birth. A Jew is an individual who either converted to Judaism (himself or herself) or was born to a mother who either converted to Judaism (herself) or was born to a mother who either converted to Judaism (herself)… However, that connotation, which distinguishes between the in-group and the out-group, in turn determines the denotation of the in-group: the individuals who make up that in-group, with their Jewishness being only one of their characteristics. It’s possible to take that set of individuals and then study their other characteristics: their psychology, biology, etc.
4. Why is Judaism such that Jewish identity is passed down matrilineally instead of patrilineally? Some possibilities: (a) Mothers more reliably pass down tradition than fathers. (b) Judaism is a “sexually defensive” religion, which goes along with matrilineality. By contrast, a “sexually offensive” religion, with the men invading other peoples and taking wives along the way; that goes along with patrilineality, and that’s not Judaism’s strategy.
5. (a) Across the West: If both of your parents are “white,” then you’re “white.” (b) Also across the West, although perhaps more so in America: If one of your parents—it doesn’t matter who—is “white” and the other is “black,” then you’re “black.” For example, Barack Obama is black despite his white mother. (c) In Judaism: If your mother is Jewish, then you’re Jewish. (d) In Japan: If both of your parents are “Japanese,” then you’re “Japanese.”
6. When the Jews left their homeland almost 2,000 years ago, they went in many different directions. Presumably, they all looked similar to each other at the time. However, in diaspora they all intermarried more or less with their respective local populations. Judaism not being bilineal, like whiteness or Japaneseness, but instead being matrilineal, means that the Jews gradually turn into their host population, racially speaking (even without taking conversion into account). A 100% Ancient-Israelite descendant can intermarry, and if that 100% descendant is female then any children from that marriage are Jewish despite being 50% descendants. Theoretically speaking, the Ancient-Israelite blood can halve from one generation to the next, over and over. That’s why, say, some of the European Jews, look European. The Ashkenazi Jews are white insofar as they’ve intermarried enough.
7. Converts. There may be a phenomenon of converts in Judaism being analogous to 日本人より日本人. They’re “more Catholic than the pope.”
8. The hurdle to get into the Amish is higher than the hurdle to get out of the Amish. Apparently the ~400,000 Amish in America descend by and large from ~200 18th-century immigrants. And apparently <100 people—whatever the true number, the number is almost definitely so small as to be for the purpose of the present analysis none—have joined the Amish in that time. That’s despite the fact that (apparently) >10% of the born Amish leave the Amish each generation. Metaphorically speaking, the Amish is a sauce that’s getting boiled down. The Amish’s Amishness gets thicker and thicker. The most adventurous >10% leave each generation, and as a result more and more adventurousness gets boiled off. The Jews have something analogous.
9. Evolution. If a human dies before reproduction for any reason, then the human’s genes don’t go onto the next generation. One of those kinds of reasons is sexual selection. For example, a man may not be attractive enough to get a woman. But even if a human doesn’t die before reproduction, any recategorization such that the human’s lineage is no longer part of the same group means that the human’s genes, while they do go onto the next generation of humans, don’t go onto the next generation of humans of that group. For example: If a Jewish man has children with a non-Jewish woman, then the man passes on his genes, yes, but not to the Jews. Thus, Judaism has a kind of sexual-selection mechanism. The matrilineality principle is a lineal categorization principle, and with endogamy that categorization (of whether a given person is categorized as being in the Jewish lineage) determines in-group marriage eligibility, which in turn has a sexual-selection effect: interestingly, a group-level sexual-selection effect.

The logical order of primacy in an argument isn’t necessarily the same as the historical order of primacy. For example, Morris Cohen argued in An Introduction to Logic and Scientific Method (1934) that the axioms of a system are often discovered after the theorems. According to Cohen, many of Euclid’s theorems were already known to the Ancient Greeks for hundreds of years before Euclid did his groundbreaking work. Euclid’s contribution wasn’t as much to discover the theorems as to discover the axioms for theorems already known. His contribution was largely to systematize already-existing knowledge.

In other words: What was in the history of ideas come up with and made known before and after doesn’t necessarily match up with what’s logically precedent and antecedent.

I’ve always been interested in the questions of why people do what they do and why people feel and think as they do. Being of a philosophical and scientific orientation, my interest in those questions has led me to study the most philosophically deep schools of thought in economics, linguistics, and some of the other sciences of human action and the human mind.

To my surprise, though, many or even most people, at least in the modern West, find it uncomfortable to generalize about people. The problem with that is: Science, whether it’s about people or things, is about generalization. Thus, to find it uncomfortable to generalize about people is to find it uncomfortable to do science about people. In other words: To my surprise, the controversies in the sciences of human action and the human mind aren’t only about what the best models are but are also about whether models are even possible.

See below for some of what I’ve written on the psychology and sociology of that debate:

1. Is the mental subject to scientific law?
2. The Enlightenment and Romanticism

In Christian cosmogony, it was God who (1) made something out of nothing and then (2) gave that something the order that it has. In Dialogues Concerning Natural Religion (1779), David Hume argued for “a new hypothesis of cosmogony,” which was a challenge to the latter doctrine: that without God, the order in the world of matter has no good explanation. In essence, he argued that the order in the world of matter can be accounted for without hypothesizing supernatural intervention, for that order is the natural result of something that everybody knows: that some configurations of matter are more stable than others. If some matter in an unstable form by chance falls into another unstable form, then by definition (i.e., by definition of the term “unstable”) it’s unlikely for the matter to stay in that form for a long time. It’s when matter instead by chance falls into a stable form that it’s likely to stay like that. Chaos falls into chaos until it settles into order.

Interestingly: In The Selfish Gene (1976), Richard Dawkins used that Humean argument in order to contextualize biological evolution. Hume explained how chaos naturally settles into order (which is an explanation of any kind of evolution, whether biological or not), and to that explanation Dawkins added the idea of a replicator (which is how biological evolution works in that context).

Why are there so many rocks? Because rocks are especially stable. If some matter by chance falls into the form of a rock, then it’s likely to stay like that. And why are there so many birds? Not because birds are especially stable on the level of the individual, like rocks, but because birds are especially stable on the level of the group. They’re especially good at replicating themselves, and thus keeping the group in existence, before themselves falling out of existence.

That Humean argument, however, falls to thoroughgoing subjectivism. The difference between chaos and order isn’t inherent to the world of matter. The difference instead comes out of something subjective: categorization.

Rocks are stable because rocks are rocks whether they’re big or small, rough or smooth, etc. But why categorize like that? A big “rock” can fall and break into small “rocks,” and a rough “rock” can be made into a smooth “rock” after enough time in a river. Our categorization scheme is such that through those transformations they’re all still “rocks.” How stable! Theoretically speaking, though, it’s possible to use any categorization scheme that you want. Anything can be thought of as staying the same through any transformation, and anything can be thought of as not staying the same through any transformation. It’s possible to imagine a categorization scheme that puts even rocks into chaotic flux.