There are certain tactics in post-Feldman concert music (or pre-Feldman ritual music) that are easy to define but hard to talk about. Topping the list are repetition and silence, two devices that are anything but uncommon. Certainly there's no trouble recognizing them (nor their cousins near-repetition and near-silence), but critically quantifying them is another matter. We might like a sort of meditative mental remove that they cause in us, but what is it that makes them good?

Science Is Only a Sometimes Friend, Aaron Siegel's suite for organ and eight glockenspiels, does not have embedded within it answers to any such questions. If anything, it only clouds the issue. With enormous precision and carefully crafted modulation, it easily falls in place behind the studies of Glass and Reich, and if one was of a mind to bring it down a notch they might well characterize it as new age music played too fast. That would, however, be putting the clever before the horse, because Science... is a plain old pleasant listen.

If the subtle variations within its construction are overlooked, it could be said (like Glass and Reich) to be quite simple. An organ in the background holds a succession of midrange root tones and clusters, varying every five or ten seconds (sometimes more quickly) as the glocks work in unison quarter notes within the harmonic halo for 41 minutes and 36 seconds. That's really all the casual listener needs to know. The mood struck is somewhere between serene and peppy (inclusive of both), which is quite a nice state to be in. What the music really trades on � as with the aforementioned composers � is a satisfying feeling of predictability coupled with the intrigue of being curious what will happen next (ie, unpredictability). The result is a tension between two opposing forces, neither relying on the anxiety of dissonance � in fact barely even making use of contrast.

So is Siegel's accomplishment here being more complex than he seems? No. That is all dismissible intellectualization. The achievement here is the making of an invigorating listen.