Seventy years after the founding of modern Israel, expressions of anti-Semitism are still all too common, from Britian’s Labour Party and America’s Women’s March to the Iranian regime and the United Nations Human Rights Council. Since I began writing on anti-Semitism half a century ago, I am still continuously confronted with the question: Why? My answer has been that for accidental reasons, Jews have constantly found themselves opposing dominant ideologies of the times.

Thousands of years ago they bet on a religion drawing on a sacred book. The rest of the world was still illiterate, betting on oral traditions and local deities. Memories are mutable and among illiterates lead to flexible behavior. In contrast, a literate religion anchored and guided people no matter where they found themselves—reluctant to accept newer books, sacred or not. Starting with Antiochus Epiphanes around 170 B.C., Hellenistic rulers complained that only Jews among all conquered nations refused to adopt Greek laws and beliefs. Both the Greek and later Roman and Christian authorities interpreted the Jews’ adherence to their faith as a refusal to recognize the authority of the state.

Later, as Jews dispersed around the world, they stood out again. Other small tribes disappeared—either killed or absorbed and assimilated into bigger ones. Jews, despite persecution and some assimilation, survived through the centuries. What to make of that? In part it was still their sacred book. But it was also their dispersal. In some places, such as Spain, they disappeared. Yet they survived in more tolerant lands.

As with literacy, lack of geographic concentration had advantages and disadvantages. The greater their number, the greater the chances of political, rebellious and military clout. But smaller groups have to rely on stronger solidarity and individual effort, the education for both of which becomes part of their deeply ingrained culture. Consider the Passover story. Jews were a loosely related group when they arrived in Egypt; they became a nation only after overcoming the slave mentality. The matzo—unleavened bread—stands literally in the Exodus story for not having time to bake bread. But it is also a metaphor: The Jewish nation was only “half baked” before leaving for the Promised Land.

Which brings us to the Jews’ disproportionate scientific, commercial and financial successes. The culture of self-reliance has been a necessity. There is no alternative for a people too small to achieve much through politics or military might.