Why bother?

A reader asks, ''Why bother with the latest in art when we already have the greatest paintings and sculptures in the world hanging in our museums?'' ''And why,'' she adds, ''take the time to run around to dozens of out-of-the way galleries in search of the new, when one trip to a museum will prove that newness in itself means nothing?''

I've asked myself those same questions, especially during long, hot days pounding the pavements looking for bright new talent, or for art that doesn't mimic something already in existence. Wouldn't I be better off, I grumble, sitting in front of a Rembrandt or a Vermeer in a museum? Aren't they, after all , the best of the best, and far superior to what I could ever hope to find in a SoHo loft or an offbeat basement gallery?

Perhaps. But life doesn't stand still. New artists appear all the time, and some may become even greater than Rembrandt or Vermeer.

The old masters, after all, are always with us, while new talent must be acknowledged and supported if it is to flourish. For those who disagree, who insist that suffering and obscurity are essential to an artist's development, let me point out that the misunderstood great artist who dies unrecognized is a rarity, that almost all artists of stature had at least some measure of support - if not actual fame and glory - relatively early in their careers.

But that isn't the important point. What matters more is that new art can tell us about the dreams, foibles, and ideals of our time, and that it can communicate the enthusiasms and passions that differentiate our period from all others. New art need not be great or even first-rate to do that, as long as it's alert to what's going on and engaged in one way or another in giving it form.

Unfortunately, we often confuse this alertness with being ''with it'' and assume that only those artists working in the accepted or fashionable modes of expression really have their fingers on the pulse of their times. Actually, the majority of such artists merely reflect the surface characteristics of their culture and its art, and lose most if not all of their effectiveness the minute the fashions of their generation are replaced by those of the next.

The genuine artist sees and feels more deeply and gives significance to that experience. The work itself may outwardly resemble the fashionable art of the day, or it may appear so traditional or idiosyncratic as to seem reactionary or a joke. Whatever, it will probably still be around and gaining in impact when all the merely fashionalbe ''art'' has vanished from view.

Such work may not even then be acknowledged as truly important, but it will gradually prove that it is art. Its luster, in a century or so, may dim, and it may join the ranks of the thousands of good to excellent older works that impress us when viewed, but that are then forgotten in the face of the truly great art of the period.

But who knows? It may indeed turn out to be so true, alive, and universal that men and women centuries from now will take delight in it, or cherish it for its deeper implications. It's unlikely, of course, but it can happen.

The trick in examining new art lies in looking beyond the obvious, and in sensing qualities and attitudes not particularly apparent because of the artist's immaturity or the influence of a powerful teacher.

I doubt very much, for instance, that I would have given Jackson Pollock's ''Cotton Pickers'' a second glance had I come across it in the mid-1930s, even had I known he was a student of Thomas Hart Benton and still in his early 20s. The painting simply isn't distinguished enough, although in retrospect, it does reveal the kind of suppressed passion and impatience with an inherited style typical of young artists about to erupt and to move forward on their own.

What happened to Pollock in the decade after the execution of this canvas is a significant part of modern art history. Assuming it was painted in 1934 (a later date seems unlikely, considering the nature of what he was doing from 1935 on), it was followed by works in which extraordinarily explosive energy was channeled into forms that became increasingly turbulent and two-dimensional.

He moved quickly. By 1936 he was experimenting with ''over-all'' compositions , and by 1938 he was well on his way to the passionate, often violent, imagery for which he was to become so famous in the mid- to late-1940s.

When I first saw Pollock's work in 1947 or 1948, he was already a full-blown ''drip-and-blob'' painter, and the object of both intense derision and considerable respect. I was an art student at the time, and totally confused by the two or three canvases of his I had seen.

I remember wishing he and his work had never happened (I was painting neat little ''magic realist'' allegories at the time), but I also knew that since they had, things would never again be quite the same in American art.

I was right. Pollock and the other members of what would later be known as the Abstract Expressionist movement altered not only the face of painting but the manner in which we relate to it as well. There is a good chance he will go down in art history as the most important American painter of the century, and as one of the dozen or so major figures of 20th-century modernism.

And yet I wonder. Could all that have been foreseen in this intense but immature canvas? I think not.