I'm afraid I'm getting a bit off topic here, but I feel I must clear up some confusion. This thread seems to be more focused on Christian theology. If I am off topic, I apologize.
...I think your definition is too narrow, I think you can be a Jew and a Christian, like Plotinus.
Not possible from the Jewish perspective. A Jew who converts to Christianity is no longer considered a Jew by other Jews.
Jewish converts to Christianity have historically been treated with suspicion at best & terrible persecution at worst by Christians. Study the Inquisition for starters on this topic. It didn't just occur in 16th century Spain. The last office of the Inquisition closed it's doors in Mexico City in 1815. This has improved since the Holocaust & converts seem to be welcome with more open arms these days. Modern Evangelicals have found they can catch more flies with honey.
I don't think your faith 100% defines your Jewishness.
Correct.
I have never in my life heard the term, Jewishness. I don't think it's a word. Insert the term, Judaism in that sentence.
I don't think that a completely secular Jew would be Jewish at all. What does "Jewish" mean? Does it mean coming from a Jewish background? But we don't say that someone is a Christian simply for coming from a Christian background even if they are not a believer themselves.
Perhaps this would be easier to understand if you think of Jews as a people, tribe or nation rather than a religion. The Tribes of Israel just happen to have their own religion. That religion has kept them bound together for generations despite being spread to the four corners of the world. You can't really apply a that Christian paradigm to Judaism. One is a people with it's own religion. One is a religion spread across many peoples.
I agree that it is hard to be clear about this sort of thing because religion and culture are so closely linked, and this is particularly true of Judaism, which, more than perhaps most religions, is especially associated with various festivals, cultural practices, and so on, and has far less of an emphasis on doctrine. Plus it does not encourage conversion of outsiders, so belief in the religion is very closely associated with coming from that culture.
Yup. There are two factors without which Judaism would not exist today: the Hebrew language & the Torah. The preservation of these throughout the generations is what has allowed Judaism to survive the millenia. Now we're leaving the subject of theology & getting into anthropology.
All of this is a major factor behind the controversy over Beta Israel (better not say "Falasha", as this is a pejorative term).
I meant no offense. The Falasha Jews I have met in Israel never indicated that they were offended by the term, Falasha. Beta works for me, too, but I have never heard this term.
The Falasha Jews of Ethiopia are fascinating becasue they were able to preserve Hebrew & the Torah despite being isolated from the rest of the Jewish world for centuries. When they were "discovered" in modern times, they knew nothing of Jewish holidays like Chanukah. The helps date their isolation. Chanukah celebrates the successful Jewish revolt against Greek rule that led to the Hasmonean dynasty in Palestine. Herod is considered the last of the Hasmonean kings despite not being Hasmonean himself. His claim to the throne was propped up by the Romans & his wife's Hasmonean lineage.
However, I do think that it makes little sense to describe someone who does not believe in Judaism or do any of the traditional cultural stuff as Jewish, since such a person is indistinguishable from everyone else.
Not so. Their mother must be Jewish & males over eight days old must be circumcised. In Nazi Germany, anyone with Jewish heredity was forced to wear a yellow star, but those days are over, thank G-d.
Similarly, if someone converts to Judaism (which normally happens only when they marry one, but it's still at least theoretically possible to do it even otherwise), then they become Jewish, don't they?
I don't have statistics, but, in my experience, conversion to Judaism most often happens when a Jewish family adopts an orphan. Adult conversion is much less common, but do happen. I know one man who grew up in a devout Christian home (father was a pastor) & decided that he wanted to be a Jew. I know a woman who decided to convert at age 16. Her family wasn't thrilled, but they didn't forbid her.
Conversion for marraige does happen, but, in a Jewish/Christian relationship, conversion to Christianity is FAR more common.
In which case, Jewishness is a matter of what you believe (partly) and what you do (mostly). Someone who believes and does the relevant stuff is Jewish, and someone who doesn't isn't. I don't really see what other criteria you could have.
The third criteria is who you are. Again, look at it from an anthropological point of view as well as theological. Jews share a common religion, but also a common language, common traditions & heredity. Besides Hebrew, there is also Yiddish & Ladino, but those aren't common for all Jews.
But Israel is a quite secular nation, so you would dilineate all the secularists from the worshipers, saying x in a familly was not Jewish because he had lost his faith? Even though he was a 26th generation Jew? I find that a little odd that peoples ethnicity has been confused with their faith so much, Jewishness is an ethnicity not a religion. IIRC to be a Jew you merely have to be born of a Jewish woman, even marrying a Jewish woman would mean your kids were Jewish(technically at least)...
Pretty much correct.
Which is why Jews are more protective of their daughters in marriage than sons, so I've heard.
I'm not so sure about this one. In my experience, Jewish parents worry about sons & daughters equally. The sons will pass on the family name, but it is the daughters who pass on Judaism. Some Chasidic & ultra Orthodox Jews still arrange marraiges. They don't want their kids chasing the opposite sex & all the immodesty that would arise from it.
But being Israeli isn't the same thing as being Jewish.
Correct. There are many Christian & Muslim Israelis. Modern Israel was founded to be a Jewish state, but it's citizens aren't all Jewish. As a Jew, I would be granted Israeli citizenship if I asked for it, but one passport is enough for me & I don't have any plans to move there.
Why should it make any difference what your ancestors were?
No offense, but I'm shocked to hear this from a highly educated theologian.
Many of the Commandments from G-d in what you call the Old Testament are specifically directed at the descendants of Abraham, Isaac & Jacob. The Covenants are expected to be kept by their descendants. A Jew doesn't expect a non Jew to circumcise his children, for example.
I disagree, I think you can be culturally linked and be Jewish and you can be religiously linked and be Jewish, and you can be both. I don't see a distinction, maybe a Jew could settle it?
I'm trying.
I'm far from being a rabbi, though.
But if you're not culturally or religiously Jewish, then you couldn't be Jewish, right? Because I can't see what else there would be to it.
See above.