The Jews | Ian Ryan

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.
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.
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.
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.
(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.”
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.
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.”
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.
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.