As a kind of prelude to what I’m going to discuss in terms of identity and the stuff of identity, I’ll point to this fine New York Times Magazine piece by Gershom Gorenberg on proving one’s Jewishness in order to marry in Israel. The pivoting grafs:

Trust — or lack of it — is the crux. Zvi Zohar of Bar-Ilan University explained to me that historically, if someone said he was a Jew, “if he lived among us, was a partner in our society and said he was one of us, we assumed he was right.” Trust was the default position. One reason was that Jews were a persecuted people; no one would claim to belong unless she really did. The leading ultra-Orthodox rabbi in Israel in the years before and after the state was established, Avraham Yeshayahu Karlitz (known as the Hazon Ish, the name of his magnum opus on religious law), held the classical position. If someone arrived from another country claiming to be Jewish, he should be allowed to marry another Jew, “even if nothing is known of his family,” Karlitz wrote.

Several trends have combined to change that. In an era of intermarriage, denominational disputes and secularization, Jews have ceased agreeing on who belongs to the family, or on what the word “Jew” means.

Among close communities, and especially among those with long histories of discrimination and persecution, trust is the engine of belonging. Trust is bestowed first by the say-so of trusted others, and when that’s unavailable, the fall-back is to documentation of heritage, lineage, an extrinsic point of connection. To marry in Israel, it’s not enough to be a Jew: someone with authority has to declare you Jewish.

That be itself seems problematic: being oscillates, depending upon the point from which identity is constituted. It works the other way, too, with those who apply for a visa to the land of their ancestors to be told by the consulate that they have always been citizens. (At college, I had a friend who was born and raised in Britain, but held an American passport through a parent: when visiting the US, it amused him that regardless of his accent and birthplace, the border agents would always say ‘welcome home’.)

On one level, it’s situational, a matter of utility. Not being able to prove one’s Jewishness to the satisfaction of Israel’s rabbinical judges is only an impediment to those who wish to marry or take advantage of the Law of Return; it won’t prevent you from holding a Passover seder. (Though having your identity questioned in such circumstances might have its own consequences.) Similarly, that grandfathered claim to a passport or to sporting eligibility only becomes part of who you are should the need or opportunity arise.

For the most part, we still function on trust and tokens, but the changing character of our interactions outpaces both the formal and informal structures in which they are used.