It's oddly fitting that fears of New Year's Eve terrorism should be cresting just as reasonable and credible voices on all sides are tamping down expectations of a widespread meltdown from the Y2K computer glitch. TV news broadcasts feature long discussions of security at outdoor gatherings; cities with jitters cancel their large gatherings while countless Americans tell pollsters they mean to stay home with the doors locked.

Not that caution about terrorism is misplaced; it never is. Practicalities aside, though, some deep-seated psychological itch is being scratched by these assertions that the turning of the calendar will bring doom.

Despite much talk of millennium this and millennium that, most public and media chatter has been of the past century; we still know surprisingly little about our predecessors the Y1K-ers, those faraway folk who, it's said, genuinely believed the world would end at the year 1000. Such religiously inspired millennarian literalism is, to say the least, a minority view this time around. But it's easy to forget how much more reasonable it might have seemed in the context of an era when religious belief was close to universal. Who could say for sure how time worked? Who could say it was a ridiculous notion that God might choose 1000 as the date for the End of Days?

For millennial terrors and fervors to work, they must tap into logical beliefs held by the society at large. Our belief in the complication and fragility of our computer networks is just such a belief. We know we depend on invisible, elaborate software that affects our every daily routine. It isn't an article of faith, exactly; it's simply what everybody knows. Our response, a couple of years back to the news that an elementary programming problem could cause those systems to break down at the turn of the millennium was, in many ways, a measure of the readiness with which we were able to incorporate this coming disaster into our worldview. It was prompt, widespread, exemplary.

Armies of programmers and managers were mustered to deal with the so-called "millennium bug," to change the old two-digit date fields to four digits in acres, no, miles of programming. (Compare the society's response to more diffuse, but potentially more dire, threats such as smoking or global warming.)

But with the well-trumpeted news that the Y2K bug is under control comes a certain void. You could see it on the cover of this week's nutty supermarket tabloid, the Weekly World News, which usually traffics in stories about aliens and psychics but devoted a huge spread to predictions of Y2K disaster. The feeling that something could go very wrong turns out to be hard to shake. It was Seattle, not a place likely to be shaken by a dread of computers, whose leaders were so spooked at the threat of terrorism (though they said the threats were not specific, only general) that they canceled a New Year's Eve bash at the Space Needle.

You can't criticize the decision to stay on the safe side. Who knows what lunatic or team of lunatics might turn a presentiment of doom into an active effort to usher it in? Maybe, just maybe, tonight will bring chaos. More likely, though, we'll have occasion to be reminded that fears with a foundation of logic may still be just fears and that our status as a rational, technological, scientifically minded culture can't inoculate us against free-floating millennial jitters.

The writer is a member of the editorial page staff.