Neon was an early medium for Bruce Nauman. There was an old beer sign onthe window of his San Francisco studio (a converted grocery store), andthat gave him an idea: make his own signs in neon.

A version of one of those early pieces, along with two decades of work, is in "Elusive Signs: Bruce Nauman Works With Light," a nationally touring exhibition that was assembled by the Milwaukee Art Museum and curated by Joseph D. Ketner II. It has been to six additional venues in the United States, Canada and Australia.

Made in 1967, that early neon, "The True Artist Helps the World by Revealing Mystic Truths" forms a spiral and can be mounted on a window or a wall. Its text is the same as its title.

This is quintessential Nauman, in that the statement is simple but any interpretation of it isn't. Neon, after all, isn't exactly the sort of medium that seems well-suited to the mystical artist. And the sentence itself is a little suspect. Do artists reveal mystic truths? And if they do, do they also help the world by doing so?

So, the meaning of the piece itself may not be quite what it first appears. If there is a truth that Nauman is revealing, it's the notion that any truth is slippery, hard to pinpoint. The declaration made in his well-lit sentence needs to be questioned.

Nauman's instinct and ability for finding the right form to embody a variety of complex ruminations has made him a leading figure in contemporary art for five decades running - deservedly so. His work has a power that is hard to put into words, as the title of this show hints.

His impact on art has been major, both in the U.S. and abroad, for his use of language, his videos and the relationship early on between his photographs and his performance art. In Robert Hughes' big book on American art, "American Visions," he is right when he writes "The most influential artist to come out of the unwieldy, hard-to-categorize mix of conceptual art, 'process' art, and performance art by the end of the 1970s was Bruce Nauman."

FLASHING PHRASES

"Vices and Virtues," completed in 1988, runs along the top of the Charles Lee Powell Structural Systems Laboratory at the University of California, San Diego. Its text consists of overlapping words - the age-old list of human strengths and foibles. There's fortitude, hope and faith, among others, on the positive end of the scale and anger, envy and sloth on the negative end. There are seven in each category and each word is 7 feet tall. The text activates at twilight every day, as a kinetic sculptural frieze.

Much as in "The True Artist," the words are charged with meaning, though he takes no insistent or didactic view toward the chosen text. It is as if he's activating a meaning-provoking machine that will affect each viewer according to his or her view of things. The glutton will see "Vices and Virtues" one way, and the devout another. This idea of setting meaning in motion, but letting others create it, emphasizes the Duchampian dimension of Nauman.

Many of Nauman's neons in "Elusive Signs" consist of words, too. "One Hundred Live and Die" (1984) comes closest to being verbose. There are 25 phrases, laid out in four vertical columns. In the first and third columns, "die" is the perennial word; in columns two and four, "live." The phrasing varies only slightly from line to line - "Live and Die," "Feel and Die," "Laugh and Live," "Sleep and Live" and so forth.

They sometimes flash one at a time, other times one row at a time, and, intermittently, all of the words light up. The writing is starkly repetitive. It's not poetic, but it's not conversational either. And it's hard to tell whether Nauman is being descriptive or declarative. Is he instructing us to "Laugh and Live" or "Spit and Die" - or laying out the word combinations?

Ultimately, the list, with its repetitions of words and light displays, becomes unsettling, even if all of its phrases aren't grim. The array of colors only adds to this effect, particularly when the colors are cheery and the phrase reads "Hate and Die" or "Smile and Die."

There is a kinship with Samuel Beckett in Nauman's neons, a sort of anti-poetic poetry. Nauman has said, "I think that the point where language starts to break down as a useful tool for communication is the same edge where poetry begins."

MEN AND CLOWNS

He uses imagery much the same way. The colors are festive, but the imagery contradicts the ebullient palette. The pictographic hangman of the everyday game appears in "Hanged Man" (1985), clowns and men in outline populate the rest. But there is nothing festive about his use of any of them.

His "Hanged Man" appears in two poses; in one, he is seemingly alive (though with a noose around his neck), while in the other he's dead.

"I added the bit about having an erection or ejaculation when you're hanged," he has said. "I really don't know if it's a myth or not."

Still, it's telling that Nauman included this detail; he wants the notion of death by hanging to seem graphic and repulsive, even if the man is merely pictographic.

Nauman's "Five Marching Men" (1985) lift their legs and display erections in illuminated unison. Their image becomes a visual metaphor about the bond between machismo and militarism - more didactic, to be sure, than his word neons.

There's a part of Nauman that wants to unmask social conventions. He appears intrigued by the psychological processes that lurk behind the stagecraft and rhetoric of war.

His use of clowns has similarities: the costumes masking, in the artist's words, "a lot of cruelty and meanness. You couldn't get away with that without makeup." In "Mean Clown Welcome" (1985), aggressive behavior and male sexuality are fused, once again, in bright, flashing hues.

Some might see these works as misanthropic. It's more convincing to view him as a passionate cynic. Like Beckett, he's a disillusioned humanist, who grudgingly clings to small shreds of hope for humanity.

One can also imagine Beckett seeing Nauman's environmental works as kindred art. The narrow "Green Light Corridor" (1970-71) requires you to decide whether you want to navigate a long, narrow space. An average adult will have to turn to the side to travel its length and many people probably can't fit.

"Helman Gallery Parallelogram" (1971) is a room, also intensely lit in green, and you navigate a fairly narrow space and doorway to enter it. Directly outside its confines, everything appears magenta. Just as his words in neon intensify language, these intensify architecture. In their disquieting way, they turn you into a kind of performer.

Seen alongside these environments, it becomes clear that his neons are language performances. Flashing on and off, in myriad combinations, his phrases, puns and anagrams take on a shifting life as we read them. They're like a linguistic fun house in the ways they distort ordinary language, even as they reveal its latent poetry.

Visit Copley News Service at www.copleynews.com.