Camp Young Judaea, a Zionist sleepaway camp where I passed a bit of my youth, tweeted this just after this year's Nobel Prize winners were announced, and it got me thinking: Did you know... Of the 8 individuals who have won Nobel Prizes this year, 6 are Jewish, 2 are Israeli, and 1 is a Holocaust survivor!

I did know, of course, and so did everyone else.

In the weeks following the announcement, I read hundreds of tweets and dozens of posts about Jews’ banner performance in Stockholm; I’ve seen it lead the TV news on all three Israeli stations that carry the news, gotten emails about it from enthusiastic relatives and overheard discussions about it in the faculty cafeteria.

While most reactions were triumphalist (“Super Jews and Our Incredible Nobel Prize Statistics,” ran one headline), some were pensive. Here in Israel, the fact that two chemistry laureates had abandoned the Jewish State when they realized it held no jobs for them, tinctured our national pride with self-censure.

Elsewhere, rabbis and pundits tried to puzzle out what it is about Jews that make them so super at science.

Broadly, two sorts of theories have been floated. One is that Jews have primo genes. Charles Murray, the Enterprise Institute scholar and co-author of The Bell Curve, set out the case for this a few years ago in an essay in Commentary called “Jewish Genius," writing bluntly that “something in the genes explains elevated Jewish IQ.” Another theory is that Jews love hitting the books, as Israeli economics laureate Robert Aumann told the army radio station Galei Tzahal: Jewish homes have overflowing bookshelves. Throughout the generations we have given great honor to this intellectual pursuit.

There are good reasons to doubt both sorts of theories. For one thing, Jewish excellence in science is a new thing. When the great Jewish folklorist Joseph Jacobs set out in 1886 to compare the talents of Jews with the talents of other Westerners, he found their performance mediocre in every science save medicine. In the first decades of the 20th century, Princeton psychologist Carl Brigham tested the intelligence of Jews in America, and concluded they “had an average intelligence below those from all other countries except Poland and Italy.” Jewish excellence in science is a phenomenon that flowered in the decades before and, especially, after the Second World War; it is too recent a phenomenon to be explained by natural selection, or even by putative ancient cultural traditions.

The real explanation of Jewish success in science lies elsewhere. The 20th century began with massive migrations of Jews, to the United States, to the cities of Russia (and then the Soviet Union), and to Palestine. In each of these new lands, Jews turned to science in great numbers because it promised a way to transcend the old world orders that had for so long excluded most Jews from power, wealth and society. Science, based as it is on values of universality, impartiality and meritocracy, appealed powerfully for Jews seeking to succeed in their new homes. It is not so much what Jews were (smart, bookish) that explains their success in science, as what we wanted to be (equal, accepted, esteemed), and in what sorts of places we wanted to live (liberal and meritocratic societies).

But I’m not the Grinch. I would have nothing against devoting a week each year to tweeting, blogging and chatting about how Jews rule when it comes to Nobel Prizes, and totally rock as scientists, were it not for the fact that our self-congratulation keeps us from seeing something that matters. Nobel Prizes are a lagging indicator. Given years after the achievements they celebrate, often to long-retired scientists, they reflect a state of affairs that existed 30, 40, and sometimes 50 years ago. They are a browning snapshot of bygone days.

What bugs me about attributing the remarkable prominence of Jews among Nobel laureates to genes or enduring cultural traditions is that doing so suggests that Jewish success in science will inevitably continue as a matter of course. Most likely it won’t. The percentages of Jews among new American Ph.D.s in the sciences has declined greatly over the past generation. In Israel, spending on higher education has continued to decline during most of the same period; to many of the growing numbers in Israel who embrace religion, the appeal of science has nearly vanished. The passions that drew Jews to sciences in such great numbers have dissipated.

Maybe this was inevitable, maybe not. Either way, there is no good reason to expect that the remarkable contributions of Jews to science will continue for generations to come. Rather than celebrating the late ripening fruit of our parents’ and grandparents’ toil, each Nobel Prize is a chance to ponder whether we oughtn’t be planting afresh the too-often neglected fields they bequeathed us.

Noah Efron teaches in the Graduate Program on Science, Technology & Society at Bar-Ilan University. His forthcoming book, "A Chosen Profession: Jews and Science in the Twentieth Century," will be published jointly by Johns Hopkins University Press and Hebrew Union College Press.