In our previous post, we briefly discussed the halakhic definition of a Jew. In this post we continue our discussion by considering a controversial view. That is the idea that the halakhic definition of a Jew as the basis for Jewish identity is insufficient. At some level this reality is already reflected in inconsistencies within Jewish communal organizations. We will explore this in future posts, but for now are setting the foundation for our continuing discussion on Jewish identity.

The notion of Judaism as a “confessional community” is often framed as a modern academic claim, yet it resonates in intriguing ways with the thought of the medieval halakhic authority Moses Maimonides. While fully grounded in halakhah, the Rambam advanced a strikingly bold idea: a person’s maternal lineage determines his status as an Israelite, but belief in the foundational principles of Jewish faith determines his theological standing. According to this view, Jewish identity is not exhausted by legal status alone.

What makes the Rambam’s position controversial is its implication that even a person who meticulously observes the mitzvot and exemplifies moral virtue might still forfeit a share in the World to Come if he rejects the thirteen principles of faith that the Rambam articulated as Judaism’s essential beliefs. In this respect, his framework bears a certain resemblance to the creedal logic commonly associated with Christianity. The Rambam framed the issue in terms of potentiality, borrowing from Aristotelian philosophy. He asked whether an acorn is an oak tree. The answer, he explained, is that it is so potentially. Likewise, someone born to a Jewish mother possesses the potential for Jewish identity but does not automatically realize its fullest meaning. This distinction allows for a conceptual separation between “Israelite” and “Jew”: the former refers to the halakhic category into which one is born, while the latter describes a theological and existential condition that must be actualized through belief.

Modern scholars have articulated similar distinctions in their own language. Jacob Neusner, for example, spoke of the difference between “Jews” and “Judaists,” the former referring to those born into the community and the latter to those who actively practice and affirm the tradition. In a more aphoristic formulation, Solomon Schechter once quipped that “a Jew is someone who Jews,” suggesting that Jewish identity ultimately lies not merely in birth but in the lived practice and affirmation of Judaism.

The Rambam also addresses the question of how one becomes a Jew by reflecting on the figure of Abraham. Drawing on Midrashic traditions, the Rambam describes Abraham as arriving at the truth of monotheism through philosophical reflection. Observing the world around him, Abraham reasoned that idols could not be divine and ultimately concluded that there must be a single, transcendent God. In this sense, Abraham becomes the first Jew not by birth but through intellectual and spiritual discovery. The Rambam therefore understands Abraham as the first convert—someone who arrived at the truths of Judaism through contemplation and conviction.

From this perspective, the convert represents the paradigmatic Jew: a person who consciously affirms the foundational beliefs of Judaism. The Rambam goes so far as to suggest that, in certain respects, the convert may even stand in a superior position, precisely because his commitment emerges from deliberate reflection rather than mere inheritance. A person born into the halakhic status of a Jew must ultimately undergo the same internal transformation—moving from inherited identity to conscious affirmation. As noted by the late scholar Rabbi Byron L. Sherwin z”l, these ideas in the Rambam are somewhat anomalous within traditional Jewish thought. Yet they illuminate a fundamental tension in Jewish identity: the relationship between birth, belief, and the personal act of embracing the covenant.

Absent additional criteria, the halakhic definition becomes problematic. If Jewish identity is determined solely by matrilineal descent, the definition risks collapsing into circular reasoning: a Jew is someone born to a Jewish mother, and a Jewish mother is simply someone who is herself Jewish. Without further theological, cultural, or covenantal dimensions, such a definition explains lineage but does little to clarify the substantive meaning of Jewish identity.

If the halakhic definition alone is used to determine Jewish identity, the status of those who convert to other religions yet continue to claim Jewish belonging becomes especially complex. A well-known example is the case of Oswald Rufeisen, often referred to as Brother Daniel. Born a Polish Jew, he was sheltered by Catholic clergy during World War II and eventually converted to Catholicism, becoming a Carmelite monk. Later he sought to immigrate to Israel under the Law of Return. A rabbinic court acknowledged that, according to halakhic criteria, he remained Jewish by birth. Because of the broader implications of the case, however, the matter was referred to the Supreme Court of Israel. The civil court ultimately rejected his claim, invoking what it termed the “reasonable person” standard: the average person, it argued, would not regard a Christian monk as a Jew.

This case illustrates the limitations of relying solely on halakhic lineage. Matrilineal descent alone does not adequately address questions of apostasy, conversion to another religion, or the role of personal commitment. Can one cease to be a Jew? From the perspective of Rashi, the answer is no: even one who sins remains a Jew. Other, less well-known views suggest that certain actions—such as formal conversion to another religion—may in effect annul Jewish identity. An intermediate position holds that a person may retain Jewish status in some respects while losing it in others, though such distinctions require criteria beyond simple halakhic descent. In other words, the traditional definition does not fully address situations in which an individual rejects Jewish belief, abandons the commandments, or formally joins another faith.

A second consequence of relying exclusively on the halakhic definition is that it can deepen divisions within the contemporary Jewish community. Consider a child born to a Jewish mother who is not raised within Judaism. Most Orthodox authorities would still regard that child as Jewish, often invoking the traditional category of tinok shenishbah—a “captured child” raised outside the Jewish community. In contrast, movements such as Reform Judaism and Reconstructionist Judaism have adopted broader criteria of belonging, including the recognition of patrilineal descent under certain conditions. These differing definitions have already contributed to internal tensions within the Jewish world, particularly because Orthodox authorities generally do not recognize non-halakhic conversions or marriages involving individuals who do not meet traditional criteria. In an era of demographic decline and increasing assimilation, the exclusive reliance on a strictly halakhic definition therefore raises not only theological questions but also pressing communal concerns about the boundaries and future of the Jewish people.

© The Times of Israel (Blogs)