'Sometimes, numbers do matter," said Dennis Ross, speaking at a conference of Jewish leaders and thinkers held in Jerusalem last week by the Jewish People Policy Planning Institute. The numbers he and everyone else there were talking about were these: There are today some 13 million Jews in the world - 5.4 million in Israel, 5.3 million in the US, and the rest scattered in far smaller Diaspora communities. The only place where there is an increase due to natural growth is Israel; everywhere else the numbers are shrinking significantly. And the overall total percentage of Jews in the world population has dropped dramatically: Jews today constitute only two out of every 1,000 people, compared to a ratio of 3.5 to 1,000 in 1970 and 4.7 to 1,000 in 1945. Why do numbers matter? Because Jewish communities abroad must maintain a "critical mass" to perpetuate themselves, and Israel must maintain a Jewish majority in the face of demographic pressures from both its Arab minority and the Palestinians with whom it shares the historic Land of Israel. So the question is: How are we to increase the number of Jews in the world or even maintain the current level? Well, my own expertise in this matter is that I've lived roughly half my life as an American Jew and half as an Israeli Jew, and here's what I've concluded about the numbers game: The notion that any steps can be taken to increase, or even maintain, the current population levels of American Jewry is, simply put, a delusion. THAT DOESN'T mean that all that philanthropy now going into Jewish education, Jewish cultural enrichment and Israel programs for young American Jews, is a waste. Far from it. It is important that, at least in the US, the most powerful nation in the world, there remain a viable, successful, influential and, at least in the near future, self-perpetuating Jewish community. And it will take all the various programs cited, and probably a lot more, just to minimize the societal trends (assimilation, intermarriage, low birthrates) that are shrinking the American Jewish population. (This includes the Orthodox abroad, because despite their high birthrates, assimilation in the Diaspora has also whittled down Orthodox communities in the past two centuries to the point at which they are a minority within the Jewish community as a whole.) So by all means the Diaspora should, with Israel's help, invest in its own future. That future, though, will have to be better educated and more committed Jewish communities - that will also be smaller and smaller as the years go by. SO BEFORE we get to the how of trying to increase the number of Jews, let's agree on the where. One thing is stunningly obvious from the figures noted above and the trends they are indicating: The only place the Jewish population can grow larger, or even remain stable, over the long term is in Israel. The Israeli Jewish birthrate (including that of non-haredi families) is higher than that of Jewish communities elsewhere, leading to a small but steady growth. Still, the remarkable jump in Israel's Jewish population since 1948, from 600,000 to nearly 6 million, is largely due to immigration, not birthrate. That migration has been hugely significant to the numbers game because it's not simply relocating the world's Jews - it's moving them from Diaspora communities where their numbers have been shrinking to a Jewish society in which they're growing. That process may be coming to an end, though, unless there's a dramatic rise in aliya from the US in the coming century. Frankly, I just don't see that happening, no matter how much life in Israel improves or how much investment is poured into Jewish education in the US and into such programs as birthright. Regardless, Israel will need new immigration, for its own demographic needs and the simple fact that it is one of the world's most dynamic economies. And in that need lies the answer to the numbers game - assimilation. Not the assimilation from Jewishness found in the Diaspora, but the assimilation toward Jewishness here in Israel. For even as Jewish leaders and thinkers debate the numbers issue and Israel's political and religious establishment remains stalemated, a remarkable process is already under way in this country. Israel, in the past two decades, has absorbed hundreds of thousands of immigrants who are not Jewish. They are mostly from the former Soviet Union, but also include growing numbers from the developing world, including the thousands of Falash Mura of Ethiopia (almost all of whom are expected to arrive here by the end of this year), the children of foreign workers (1,500 children born to foreign workers here were granted citizenship last month), and the growing number of "lost Jewish tribes" (most of whom undergo conversion abroad), such as the Burmese Bnei Menashe. This increasing trickle of new Israelis is increasingly being seen as the first drops of a potential flood of immigration here from developing nations, drawn here either by a First World economy and society (there's good reason why Sudanese refugees are traversing the entire length of Egypt to make their way here), a distant connection to Jewishness, or both. The numbers are growing to the point that some officials, claiming these newcomers threaten to undermine the state's Jewish character, are calling for a tightening of the Law of Return, greater efforts to deport illegal aliens and, in reaction to the Sudanese refugee issue, fencing the entire length of the border with Egypt. Yet rather than seeing these newcomers as a threat, why not as an advantage? Already most of the young generation of the immigrant groups mentioned above, whether they are halachically Jewish or not, identify themselves with the Jewish majority. Over time, they will increasingly assimilate into the dominant Jewish culture; despite the difficulties, some will even go through the official conversion process that is way harder than it should be, and even those who don't will speak Hebrew, observe the Jewish calendar and receive a Jewish education far deeper than the majority of Diaspora Jews. Rather than fight this trend, we should welcome it, encourage it and try to control and influence it for the better, both in the interests of those who want to join us here and those who already have. Though these issues may not be on the agenda of conferences on the future of the Jewish people, these are the realities of Israel today that will actually shape that future. In creating a Jewish state, its founders created a laboratory in which unprecedented experiments will take place in the growing of the Jewish people, a society in which non-Jews will assimilate into Jewish culture, reversing the Diaspora process. These Jews of tomorrow may look and sound different than those of yesterday and today - but they are our future, and they're growing in numbers before our very eyes every day.