By Rabbi Yerachmiel D. Fried

Dear Rabbi Fried,
After meeting several atheists who described themselves as “culturally Jewish,” reading an article about an atheist (describing himself as “formerly Jewish” and vehemently advising “Jewish atheists” to drop the “Jewish” part and just be atheists), and thinking back to a college class about Judaism in America where on the first day, the professor asked us if Judaism was a cultural, genetic or solely religious designation, I’ve begun to wonder what really makes a Jewish person?
Judaism is cultural as well as religious, but most religions have a cultural and religious aspect. Still, Christians who become atheists are not described as “Christian atheists.” True, these formerly-Christian atheists might still celebrate their cultural holidays like Christmas, but many people celebrate Christmas as it has become its own, money-driven, only slightly-religious powerhouse — dominating our commercial sphere for what feels like half the year. For many, Santa Claus is the holiday’s deity.
Does Judaism have a genetic component? Some groups of Jews do share similar genetic markers, but not all. The “mixed multitude” of Jewish people spans the world and there are genetic differences among them, not even counting the people who have converted to Judaism. Despite hearing assertions that one can be “half-Jewish” because of one parent or another, I don’t believe that Judaism is strictly genetic. (This is a topic that is passionately debated).
— Jena M.
Dear Jena,
There are known to be genetic similarities in various groups of Jews, such as Ashkenazic Jews, as they are known to be of higher risk as carriers of certain genetic diseases, and for this reason are advised, when two Ashkenazic Jews are contemplating marriage, to both be genetically tested to rule out the possibility they are both carriers of any such diseases (see related story on p. 5). Although this may be true, it has no bearing on their or any other Jew’s Jewishness per se. The true marker of a Jew is a spiritual one, not a genetic one. To claim that Judaism is a race is quite ludicrous, given the multitude of races within the fold of the Jewish people. The very fact that Judaism accepts converts states unequivocally that one need not have “Jewish genes” to be Jewish!
This, then, leads us to your question: If Judaism is a spiritual and not genetic connection, how could those Jews who reject any spiritual connection to Judaism be considered Jewish? This is a very timely, as well as painful, question especially in light of the recent, much publicized Pew report which showed that over 30 percent of millennials identify as Jewish not based upon religion. Many, sadly, reported their connection was more through Jewish humor than through Jewish religion. Is, then, this growing population of non-spiritual, often atheistic Jews really Jewish?
The answer, exclaims the Talmud, is a resounding YES! The Talmud comments on a verse in Joshua (7:11), which says “the Jews have sinned.” The Talmud derives from the wording of the verse which did not say “the nation has sinned,” but the “Jews” have sinned that a Jew, even though he or she sins, is still considered a Jew. The classical commentator Rashi explains that although a Jew may have sinned, the holy name of “Jew” remains upon him. The sages say that this applies even if a Jew didn’t only transgress a random sin, but even if they have rejected Judaism completely and become idol worshippers. This is borne out by the Code of Jewish Law which codifies the comments of many early authorities who hold that if a Jewish idol worshipper who rejected Judaism returns to Judaism, there is no need to “convert” them back to Judaism; they are already Jewish and simply strayed off the path; now they are back.
As you asked, how is all this to be understood? If they rejected their spiritual connection, what makes them Jewish? Why would such a Jew not need to convert back to Judaism?
The answer is, the mystical Jewish soul. When one is born Jewish or properly converts to Judaism, they are endowed with a Jewish soul. That soul is the essence of their being. Cognizant of it or not; like it or not, traditional Judaism believes it is the very fiber of both their being and their Jewishness. It is that soul, not their genes that connects them in a very deep way to all other Jews in the world, as well as being their link in the chain which connects them to their Jewish spiritual ancestors all the way back to Abraham. It is to the spiritual descendants of Abraham that God promised the Land of Israel, not only to those of his genetic progeny. This refutes the claims of anti-Semites who misuse the scientific research showing Jews are not necessarily genetically connected or from Middle Eastern descent to attempt to nullify the Jew’s historic claim to Israel. I agree with you that there is no such thing as half-Jewish, which is another subject but built upon the above as well; either one has that soul or not (like there’s no such thing as half-pregnant). I hope this answers your question.
Rabbi Yerachmiel D. Fried, noted scholar and author of numerous works on Jewish law, philosophy and Talmud, is founder and dean of DATA, the Dallas Kollel. Questions can be sent to him at yfried@sbcglobal.net.