How slight or frivolous can something get and still be art? Does a doodle qualify? And how about a few blobs of paint, two tin cans tied to a post, a live pig sitting all by itself in a gallery, or bright red paint tossed into a swiftly moving stream? Can they be considered art?
In an immediate, superficial sense, it all depends on whom one asks. All the above ''techniques'' or activities have at one time or another been taken very seriously by those who decide what goes into our museums - and ridiculed as worthless by at least an equal number of experts. The final determination will be up to art history, and it, I assume (and hope), will decide on the basis of what the individual did with a particular material, and not on the nature of the material itself.
The list of things that artists, critics, and curators have claimed as worthy successors to what Rubens and Monet produced is endless. Almost everything - even self-mutilation - has been attempted in the name of art. This century, in particular, has been extraordinarily generous in permitting such things as holes dug in the ground, pebbles strung on wire, steel rods driven into a field, blinking neon lights, and almost anything else anyone can think of to become the equals of oil paint, marble, or fresco in the production of art.
The results have been fascinating, beautiful, and important - or silly, worthless, and demeaning - depending on whom one asks. On such matters the art world seldom agrees, or even finds sufficient common ground for intelligent discussion.
The traditional-minded seem most easily offended by three-dimensional objects that depart from the classical ideals first given form by the ancient Greeks and then modified over the centuries by numerous sculptors up to and including Rodin. Everything started to go wrong with Brancusi, became worse with Picasso, Arp, and Calder, and reached the final dismal depths with Eva Hesse. Even Henry Moore is too tainted by modernist ideas let alone such artists as Klein and Beuys.
Work in bronze, string, or plastic which looks like nothing ever made before tends to bring greater outrage than does similarly ''revolutionary'' work on canvas or paper. Only Pollock's drips and blobs of paint caused as much anger and derision as Beuys's tubs of lard and felt-covered pianos, and nothing triggered as much confusion as Tinguely's self-destroying mechanical constructions.
How that could be art was beyond comprehension, and many decided then and there that modernist sculpture was a total loss. They couldn't have been more wrong. No other form of contemporary art has had more deeply dedicated and forward-looking creators than that mode of expression that projects ideas through three-dimensional structures and devices and works with actual rather than implied space. Such artists as Robert Irwin, Christo, James Turrell, Claes Oldenburg, Alice Aycock, and Athena Tacha - to name only a few - are expanding the very concept of sculpture in a manner and to a degree unthinkable two or three decades ago. And several older sculptors are continuing to extend their own visions of three-dimension-ality considerably beyond what they had originally perceived them to be 40 or 50 years ago.
High on the list of these older sculptors is Isamu Noguchi. He was born in Los Angeles in 1904, returned to Japan with his family in 1906, was sent to Indiana for schooling in 1918, and was apprenticed to the sculptor Gutzon Borglum in 1922. Success came quickly and never deserted him, making him one of the handful of living artists who deserve to be called modernist ''old masters.''
Noguchi's work has ranged from breathtakingly pure abstract sculptures to dramatic stage sets for Martha Graham, and has included designs for gardens, bridges, and fountains for large environmental projects and small paper lanterns. His art fuses modern Western and traditional Japanese forms and ideas in ways that respect his cultural roots without in any way inhibiting his restlessly innovative spirit.
The latter has been responsible for several pieces that particularly provoke his more conservative contemporaries. They find them either too severe, too ''Japanese'' in conception, or too esoteric. When, in 1947, he designed a ''Sculpture to Be Seen From Mars'' - which consisted of a face whose nose was to rise one mile above the surface of this planet - they refused to take him seriously as an artist, although a few still acknowledged his genius for designing parks and playgrounds.
''The Cry'' is one of his most imaginative - and for his critics, one of his most maddening - works. It is made of balsa wood, stands seven feet high, and is so constructed that the attached smaller element moves very slightly in response to air currents and vibrations.
The question, of course, is what does it ''mean''? If asked, Noguchi, I'm certain, would only respond with a smile. And why not? Certain things cannot be explained, they can only be sensed and intuitively understood.