Don't pick up the 10-disc Ultimate Matrix Collection expecting to hear the Wachowski brothers explain what the heck happened. For all its material the trilogy; its Animatrix spin-off; the production companion, The Matrix Revisited; and extras both new and repackaged the spotlight-shy sibs are as scarce as ever. In a written intro, they beg off supplying their own tracks for fear that they'd be squelching individual interpretation; instead, they leave the commentaries to dazzled philosophers Cornel West (who cameos in the series) and Ken Wilber on one track, and to a trio of underwhelmed critics on another. When this yea/nay novelty clicks, we get moments like a Reloaded reference to Superman that shows one side spouting Nietzsche and the other side grousing about the pointless layering of one comic-book mythology on top of another. New Revisitedfeatures do a nice job delivering behind-the-scenes glimpses different from those included in initial DVD releases. (Dig that freeway chase choreography again...and again.) Meanwhile, the ''Roots of The Matrix''disc offers an intriguing hour-long documentary exploring the plausibility of a real Matrix, with writers, futurists, and hard-science types pointing out how, say, total immersion in a videogame isn't so very different. But then a second doc trots out one academic after another, almost Agent Smith-like, for further philosophical deconstruction of the films. Eager as the Wachowskis are to forcibly free our minds, they shouldn't forget that much of the original joy in watching their work was just in kicking back and saying ''Whoa!''