If you look like Arlo Guthrie with peyos, you were probably at the Acharit Hayamim concert-shebang in Bat Ayin last week. I've been going to that event since before it got its name, when only a few dozen people came to the middle of nowhere to hear, among some more polished stuff, an odd assortment of cave-dwelling acid-heads jamming and trying out new stuff (occasionally involving rooster imitations -- don't ask). They've gone a bit mainstream since then (i.e., they charge money), but I still enjoy the chevre.

It used to be that, if you were talking to someone who gets it, you could describe any Jewish crowd with a couple of words. Chaim Berlin -- Brooklyn College night gang, YU Gushies, NCSY BTs from Lake Wobegon, Lakewood shidduch-shoppers. But a typical gang at this event might consist of a guy in beard, peyos and turbin (suggesting a sort-of Ben Ish Chai effect), a guy in tee-shirt and jeans, short hair and no headgear, a guy looking like Scottie just beamed him down from Woodstock, and of course Arlo Guthrie with peyos. (I'll skip the female profiles; suffice it to say that the analogues were all present and accounted for.) I suppose one day we'll just refer to them as, you know, the Acharit Hayamim people.

Of course, they're engaged in deliberate stereotype-busting. Stereotypes are based on the observation that habits of manner and behavior tend to correlate. If you wear a certain kind of head covering, you probably wear a certain kind of clothes, daven in a certain kind of shul, hold certain views and have friends who are just like you in all those respects. The mixing-and-matching in Bat Ayin reflects a conscious attempt to make stereotypes like that seem ridiculous.

The dynamics of the process remind me of a web search algorithm called scatter-gather. It works in two stages. First an initial collection of documents is clustered automatically into sub-collections each of which is somehow coherent and labeled by its unifying theme (e.g., topic). The searcher chooses a few topics from among these that reflect the area of interest. The documents in the chosen topics are then thrown back together and re-clustered. Lather, rinse, repeat.

Now start with a bunch of Jews. They naturally cluster according to the characteristics that are relevant in a given time and place. (For example, after massive dislocations, ethnic divisions reflecting country of origin might be most prominent; under other circumstances, levels or styles of religiosity might be more decisive.) Then some of the clusters drop out of the game and the remaining ones are re-clustered, possibly along completely different dimensions. When this happens, the old stereotypes become merely vestigial; they no longer have any real descriptive force. So, if you're still awake after that little riff, I admire the Acharit Hayamim gang for being harbingers of the death of the old stereotypes. (And, yeah, it's because some clusters are dropping out of the game.)

And, before you get on my case, I'm aware that more than a few of this chevre tend to think in a rather loose associative manner and some cognitive discipline might serve some of them well. Amusing case in point at Acharit Hayamim: a certain rav from Tekoa was doing shtick between Ehud Banai songs. He was wearing a bekeshe and shtreimel (even though it was an ordinary Tuesday night) and he did a performance (no other word for it) of kiddush levana (most of the rest of us had already done that on Tisha B'Av). He insisted that everybody actually lunge for the moon when he said keshem she-eini yachol lingoa bach, declaring that one day such lunging will indeed succeed. Why this should be so was unclear. Maybe he noticed that the pasuk's conclusion that kach lo yuchlu oivai lingo bi has never worked out, and decided that the premise must be equally unreliable. More likely, he was flattering his audience by letting them know that nothing you say actually has to make any sense, as long as it sounds vaguely Utopian.