Are the Jews a race or a religion? What are the applicable criteria? And who decides? This has been a long-running saga in the Diaspora as well as in Israel. In England, the whole question has blown up as the result of a high-profile lawsuit filed by the parents of an 11-year-old boy who was denied admission to a top Jewish school. The school, known as the Jewish Free School (JFS), is paid for by the British taxpayer but is restricted to Jewish pupils. Who decides who gets in? The office of the British chief rabbi, head of the biggest - but not the only - group of Orthodox synagogues in the United Kingdom. The chief rabbi's test, applied by the school, was based on parentage. A child whose mother was not Jewish would be turned away. That sounds simple enough, but the problem arose with conversion. Conversion by a non-Orthodox synagogue was not recognized - but conversion by an Orthodox rabbi, even in Israel, was by no means guaranteed to be kosher either! IN JULY 2009 the English Court of Appeal branded the chief rabbi's motherhood test "racist" and therefore unlawful. But the school's lawyers didn't exactly help their case by proposing two different definitions of Jewishness. They accepted that the 11-year-old at the center of the storm - who was teased at his non-Jewish school for wearing a kippa - was Jewish in race but not in religion. Needless to say, this illogical and self-contradictory position was rejected by the court. So who was right? Neither, since both failed to understand the true nature of Judaism as a communal religion. The argument accepted by the Court of Appeal is simple, not to say simplistic: "Jews constitute a racial group" - so discriminating against someone on the grounds that he is not Jewish is racial discrimination. The judges concluded: "Eligibility must depend on faith, however defined, and not on ethnicity." The court did not try to define "faith," but the stress it placed on this term reveals that it was senselessly trying to impose a Christian definition of religion on Judaism. Unfortunately, the court did not have the benefit of expert evidence regarding the true nature of Judaism. Christianity is a creed religion - a religion based on a set of professed beliefs - whereas Judaism is a communal religion, based on membership in a community. In the pre-Christian world communal religions were the norm; a person's religion formed an integral part of his national identity. That is why ancient religions did not have names separate from those of the societies to which they belonged. For example, what was the name of the Roman state religion? Answer: it had no specific name. The terms "Jew," "Jewish" and "Judaism" derive from Judah, the name of the ancient Jewish kingdom, which in turn was based on the name of the Jewish tribe of the same name. A Jew's religious identity was part and parcel of his or her communal identity. So, when Ruth in the Bible converts to Judaism, she solemnly declares: "Your people shall be my people, and your God my God." SHOULD THE school have won the case on the basis of the chief rabbi's definition of Jewishness? No. The school also failed to grasp the key concept that Judaism is a communal religion. Had it done so, it may have been able to persuade the court that selecting pupils on the basis of their Jewishness was not racist but truly religious, since the religion in question was a communal one. Instead, they agreed with their opponents "that Jews are an ethnic or racial group." They argued that the schoolboy in question was Jewish by race but not by religion. So, instead of having a single definition of Jewishness - which the concept of communal religion would have given them - they ended up with two conflicting definitions. Not surprisingly, this self-contradictory position didn't impress the court. Because Judaism is a communal religion, the only sensible position is that a person is Jewish either for all purposes or for none. So who decides? Why should it be the chief rabbi, who heads only a part of the British Orthodox Jewish establishment? Another problem is that the chief rabbi's definition is so narrow that it excludes not only Reform, Progressive and Liberal conversions but even some by other Orthodox rabbis. This narrowness has resulted in the decision-making power being taken from the chief rabbi and given to the secular courts - hardly a satisfactory solution. IN RESPONSE to the court decision, the Office of the Chief Rabbi has now jettisoned its previous definition in favor of a "religious observance test" to determine an applicant's "practice and belief." Shabbat observance is now apparently going to be a requirement. So, while broader than the old test in some ways, this new highly subjective test is going to exclude some candidates who would previously have passed muster without question - for example, those from non-practicing and non-believing homes but with impeccable motherhood credentials. The new test is unlikely to solve the problem because it shares a central weakness with the old one: a failure to understand Judaism as a communal religion. The real question to ask, which neither the old nor the new test does, is very simple: Is this applicant for admission to a Jewish school a member of the Jewish community? If the child or his previously non-Jewish mother - or father, or both - has identified with the Jewish community to the extent of going to the trouble to convert, then it would make no sense to exclude that child. There is only one Jewish community, embracing all those who regard themselves as Jewish. Anything less would amount to self-destructive arrogance. Judaism is never going to attract large numbers of converts, but those who are prepared to undergo the process of joining the Jewish people should be given every encouragement. The writer was formerly Professor of Classical Civilization at Witwatersrand University, South Africa, and is a sometime Fellow of St John's College, Cambridge. He is a practicing barrister in London and the author of 15 books.