JERUSALEM — Most Israeli Jews marry within their own religious or secular subgroups and inhabit largely separate social worlds, according to the findings of a new survey exposing the deep gulfs over the role of religion in Israeli politics and society.
The first in-depth study of religion in Israel conducted by the Pew Research Center in Washington, released on Tuesday, found that religious and social divisions are reflected in “starkly contrasting positions on many public policy questions,” and in profoundly differing attitudes toward the character of Israel.
So while 89 percent of Israel’s secular Jews, who make up 40 percent of the population, think democratic principles should take precedence over Jewish law on issues where the two collide, 89 percent of Israel’s ultra-Orthodox Jews, a smaller but fast-growing group, think the opposite.
The study found substantial differences among Israeli Jews on crucial questions. Even among self-identified centrists, opinion was split three ways on the issue of Israeli settlements in the occupied West Bank. Over all, a third believed the settlements hurt Israel’s security, a third thought they helped security and the remainder said they made no difference.
“These groups live in the same country, a small country, but it’s almost like they live in different worlds,” said Alan Cooperman, Pew’s director of religion research.
“All societies have various kinds of fractures and divisions,” he said, “but the size of the fractures in Israel, from a pollster’s point of view, are jaw-dropping.”
He described those fractures as “ethnic and religious and deep and very real and alive,” with practical implications “on policy questions like whether public transportation is running and planes are flying on the Sabbath.”
One striking finding was that nearly half of Israeli Jews surveyed said that Arabs should be expelled or transferred from Israel. Israeli pollsters questioned the usefulness of the result, however, because the Pew question did not specify, for example, whether such transfers would be voluntary or compensated financially.
President Reuven Rivlin of Israel, who has spoken passionately about Israel’s need to bridge gaps between its various “tribes,” said the survey “points to the need to address our problems at home, more than ever.”
The Jewish majority is still united by various factors, including support for Israel as a refuge, with unlimited Jewish immigration. Most Israeli Jews perceive anti-Semitism as being on the rise around the world and believe Israel is an essential component of the long-term survival of the Jewish people.
And despite the diametrically opposed positions of some sectors regarding the place of Jewish law, the survey indicates that 76 percent of Israeli Jews believe Israel can be both a Jewish state and a democracy. Among the Arab population, 64 percent do not believe it can be both.
Local experts said that although Israelis frequently poll themselves on similar issues, the unusually large scope of the Pew survey gives it weight and validity.
The survey was conducted through face-to-face interviews in Hebrew, Arabic and Russian among 5,601 Israeli adults from October 2014 through May 2015.
The margin of error was three percentage points for Israeli Jews over all, but higher for each of the subgroups, including Christian, Muslim and Druse minorities that constitute about a fifth of Israel’s 8.5 million people.
The new study follows a major Pew survey of American Jews published in 2013 that found a significant rise in those who are not religious, marry outside the faith and are not raising their children Jewish, resulting in rapid assimilation in every branch of Judaism except Orthodox.
Jews in Israel are more religiously observant than those in the United States, according to the two studies, including those who define themselves as secular. Nearly two-thirds of Israeli Jews say they keep kosher at home, for example, compared with about a quarter of Jewish Americans.
Israelis who describe themselves as Haredi, the Hebrew term for ultra-Orthodox, make up about 8 percent of the state’s adult population, and are the fastest-growing group. Religious (“Dati”) Jews are 10 percent of all Israeli adults, and those who call themselves traditional (“Masorti”) represent 23 percent.
While 56 percent of Dati Jews place themselves on the political right, Haredim and Masorti Jews are equally likely to place themselves on the right or in the ideological center. Most secular Jews — 62 percent — identify as centrists. Eight percent of all Jews surveyed defined themselves as leftists.
Tamar Hermann, who directs surveys for the Israel Democracy Institute and was an unpaid adviser to the Pew study, said she did not know whether to be shocked or to express reservations regarding the finding on the transfer of Arabs.
“The phrasing of the question is very blunt,” she said.
“I would feel uncomfortable incriminating the Israeli public based on that one question,” she said, adding that it would nonetheless be “used as a weapon” by Israel’s critics.
Yehuda Ben Meir, an expert on Israeli public opinion at the Institute for National Security Studies at Tel Aviv University, said that previous surveys showed strong support for “voluntary” transfer, but at the same time, “if you ask Israeli Jews, ‘Do you view the integration of Arabs into the Israeli economy and society as important?’ most will say yes.”
Mr. Cooperman, of the Pew Research Center, said Pew decided to keep the question simple, especially since there is no specific policy proposal advocating transfer on the table now in Israel.
“This is how Jews are reacting to the broad idea,” he said. “But people will point fingers at us.”
He added that the question should also be seen in the context of other findings, including that fewer than half of Israel’s Jews think a solution can be found to allow Israel and an independent Palestinian state to coexist peacefully.
“If you pull the transfer question out in isolation, I can see how it can be used for propaganda about racism in Israeli society,” he said. “It should not be viewed in isolation.”