WATCHING PETER SELLARS' Much Ado About Nothing is like walking across a room blindfolded--it's easy if you're well acquainted with the terrain but painful and confusing if you're not. Sellars has assaulted Shakespeare's script with the aid of a talented but small troupe, and of the author's carefully pointed satires and balanced symmetries he has left only fuzzy outlines.

As the Loeb production begins, two actors haltingly read the play's very conventional opening lines, their scripts in hand. After a moment or two of this parody, the actors give up, tossing away the scripts in a gesture that at least honestly declares the director's intentions.

For Sellars has brutally mashed Much Ado About Nothing's script to fit the limits of his acting company and his own self-indulgent desire to buck conventionality. His innovations in staging are often clever and amusing, like his use of several mannequins to fill various roles for which he lacked actors; but the merging of more important roles, the cutting and chopping of important scenes, and the self-consciousness of each departure from Shakespeare unnerve the audience and often make the play's plot incomprehensible. Sellars might just as well have bounded on stage, done a headstand, cried "look at me!" before the curtain rose, and let the play proceed with a modicum of sensibility.

What, then, are these atrocities performed upon Shakespeare's defenseless classic? First, Sellars has combined the roles of Leonato and Friar Francis into a new character named "Monsieur Love" (Chris Clemenson)--not a mortal sin, since the new character lives up to his fabricated name by playing matchmaker, always presiding over some new combination of lovers, and since Clemenson plays the part with a consistently benign, endearing manner.

MUCH WORSE, indeed Sellars' biggest blunder, is another combination of roles, this one of Don Pedro and Don John. Admittedly, these characters are some of Shakespeare's more faceless, Don John in particular being the classic villain-without-a-motive. That doesn't excuse the complete merging of the two, however, into an unplayable role called "the Prince" which Brian McCue understandably can make nothing of.

This particular actor-saving ploy on Sellars' part costs him an entire half of the play's plot. No one in the audience who has not read Much Ado About Nothing beforehand can make sense of the main romantic plot of Claudio (Paul Redford) and Hero (Grace Shohet) without the separate Dons.

Claudio is meant to be a dullard aristocrat, insensitive and unpoetic--his highest flights of imagination produce feeble lines like Redford's sulky performance is sufficiently imperceptive but occasionally mannered, Shohet's graceful but hard to judge, since she has so few lines.

The play flashes into lucidity every now and then when Japes Emerson's Benedick and Anne Beresford Clarke's Beatrice parry each other's verbal thrusts. Clarke assumes the stage with an assurance other performers whose roles had been mangled could not afford. Her voice is not large or overpowering; instead of ringing out, it pierces and slices--but that's an effective sound for this razor-tongued heroine. Emerson's Benedick is youthful and athletic, but not terribly well-defined; Shakespeare suggests he ought to be something of an eccentric.

The "nothing" of the play's title should apply to both plots; Claudio's charges of Hero's infidelity are the negative side, and the bond between the celebrated Beatrice and Benedick, constructed of words alone, the positive. There's meaning in Shakespeare's juxtaposition of his parody of the hackneyed romance embodied in Hero and Claudio and the thoroughly unorthodox relationship between Beatrice and Benedick. Sellars, however, is too busy moving his dummies around the stage to waste any time developing Shakespeare's main theme.

THOSE DUMMIES play an important part in the scenes with Dogberry (Peter S. Miller) and Verges (David Frutkoff), the "mechanicals" or clowns of this comedy. As the town watch and constabulary they are the ones who unravel the intrigue by which Don John (here "the Prince") convinces Claudio of his beloved's infidelity. An adept at malapropism, Dogberry conducts hearings and gathers evidence with the aid of the manic Verges, who in Sellars' production runs from dummy to dummy both to interrogate and to respond.

Both Miller and Frutkoff are effective, the former in a huge chestplate that makes it virtually impossible for him to sit down. Sellars' direction of their scenes, too, seems more careful. He dims the lights to a ghostly blue and has his pianists play wild chase music for their detection of the plot against Hero.

But no cadaver should ever endure what Sellars does to the Dogberry/Verges scenes--his chopping reduces them from a major element of the play's structure to mere comic relief. It's tempting to look at them that way, of course, and in the uncut script their scenes do go on forever. But as with all of Shakespeare's plot problems that tempt foolhardy directors to cut and re-order, this one had a point.

The lower class constables move like some inexorable natural force but eventually they do solve the mystery, in their own Keystone Kops style, and bring it to the attention of the near-sighted aristocrats. But of course in this production the mystery they solve has never been properly posed to the audience, and its solution becomes nothing more than a new confusion.

Sellars' staging matches his conception of the rest of the play; that is, there's no idea behind it, only a fanatical desire not to do things conventionally. He uses scaffolds and shrubbery well, and borrows dark blue back-lighting and candles from his spring production of The Three Sisters at the Loeb. He also matches that production's inspired use of music. Burlesque is the basic style of David Reiffel's music for two, four, six, and even eight hands, and its use throughout does much to enliven the show.

At the very end of the play, after each couple has been united, the actors--in stark white or black costumes till then--remove their robes to reveal bright, almost dayglo renaissance costumes. Like the discarded scripts at the beginning, Sellars undoubtedly meant this touch to say to the audience, "This is what I could have done, but that would have been boring."