There is a Yiddish saying about the mysteries of faith, family and fellowship that, loosely translated, proclaims: "You cannot make Shabbat by yourself." "The point is that you need the presence of other Jews around you to live out the dictates of your Jewish beliefs," said sociologist Steven M. Cohen, of the Jewish Institute of Religion at Hebrew Union College.
Shabbat creates that circle of support. Beginning minutes before sundown on Friday, it involves a day of rest, prayer, ritual feasting and ties that bind. Some of these traditions are defined by faith while others are rooted in ethnicity and culture. But the whole ancient package assumes that Shabbat brings Jews together.
So what does it mean when the first major study of American Jews in more than a decade shows that -- even among Jews who call themselves religious -- only 33 percent believe being part of a Jewish community is "essential to being Jewish"? Only 23 percent of these "Jews by religion" considered it essential to follow Jewish laws.
The results in this Pew Research Center study were, of course, even more sobering among the rising number of Jews -- one in five -- who said they had "no religion at all."
"In theory, Jews who answer 'none' when asked about their religion can still be part of the wider Jewish community. There's nothing new about that," said Cohen, in a telephone interview.
In practice, however, this "none" trend is viewed as negative by many Americans who consider the practice of Judaism to be a crucial part of Jewish identity, he said. Thus, the rising number of Jewish "nones" has many of the same serious implications as the much-discussed national rise in the number of the religiously unaffiliated among people in general.
This national survey of Jews, by the Pew Research Center's Religion & Public Life Project, is the first conducted by an institution outside the Jewish community. Jewish surveys in recent decades have consistently caused controversy because of fierce debates about how to define who is, and who is not, Jewish.
Among its headline-grabbing findings, this survey noted:
* The percentage of adults who are "Jews by religion" has declined by about half since the 1950s. While 93 percent of G.I. Generation Jews call themselves religious Jews, only 68 percent of young "Millennial" Jews make that claim.
* Only 15 percent of those surveyed said being Jewish is "mainly a matter of religion," as opposed to 62 percent who said Jewish identity is primarily about ancestry and culture. Two-thirds said it isn't necessary for Jews to believe in God.
*Among "Jews of no religion," 79 percent have a non-Jewish spouse, compared to 36 percent of religious Jews. This is crucial, since 96 percent of Jews married to Jews raise their children in the faith, while only 20 percent of intermarried Jews do so. And Orthodox Jews continue to have much higher birthrates than other Jews.
In addition to raising demographic questions about the future, the growing divide between secular and religious Jews can cause sparks in daily life, said Naomi Zeveloff, of the Jewish Daily Forward. In a recent article she noted that when Chabad-Lubavitch activists go "bageling" -- approaching New Yorkers to ask if they are Jewish -- they have an unusual way of verifying that they are on target.
One "surefire way" to know someone is Jewish, she wrote, is that "they react to your question with anger," like one subway rider who replied, "I'm not religious" when approached by Jews in typically Orthodox garb.
"If you are a secular Jew, anything goes," said Zeveloff, in a telephone interview. "Many secular Jews assume that religious Jews, especially the Orthodox, don't think they are Jewish enough and that their Judaism is somehow invalid or inferior."
Jewish community leaders, said Cohen, must face a growing hole in the middle of American Jewry as "nones" surge on one side, and the Orthodox hold firm on the other. However, they can take comfort in the fact that Jews have "invented new ways to be Jewish" through the ages.
"You can be Jewish by being religious, but you can also say that you are a Jew because your politics are liberal," he said. "We have Zionists. We have secular Zionists and we have religious Zionists, we have left-wing Zionists and we have right-wing Zionists. ... Judaism has always been a kind of cottage industry."