Before we call it 'great' . . . Is it?

I think we should retire the word ''great'' for at least a year. And do so before it loses what little meaning and effectiveness it still has.

Of what value is the word if it is used to inform us that a particular brand of tuna fish is great; that a new politician is a great human being at heart; that certain animals make great pets; and that a rising young comedian has great timing? Or if it is used to declare almost every artist of quality great?

What particularly disturbs me is that this indiscriminate use of the word helps to debase the concept of greatness itself. It causes us to see no real need for a distinction between the good and excellent.

Why, after all, make the extra effort to achieve the pinnacles of art if being merely good will do? If it is enough to be clever, novel, or enchanting? Or if fame and glory can be acquired by the relentless application of shrewdly planned publicity?

Haven't we, as a matter of fact, already gone rather far toward the belief that greatness is an outdated romantic concept that has very little if anything to do with ''modern'' perceptions of reality? And haven't we pretty much resigned ourselves that a call for excellence is, in some strange fashion, undemocratic? And that a true love for humanity demands a happy median, an extended common denominator in taste, quality, and achievement?

This notion that a love for humanity and a call for excellence are incompatible is beyond my comprehension. How, after all, did mankind manage to move from a level of mere survival to some degree of civilization, except through the persistent demand for something more rewarding than what we had? And wasn't that accomplished through excellence?

If we numb our sensibilities and divert our intelligence toward the mediocre, we will produce the mediocre. But if we activate our sensibilities and stimulate our intelligences by the examples of greatness, we ourselves will probably produce something beautiful and great.

The problem is that we tend to look only to the past for our standards, for our concepts of greatness. In doing so, we too often forget that the answer doesn't lie in the things, the great works of art of the past, but in the vision , the passion, and the ideals that brought them into being. It's not Michelangelo's masterpieces, for example, that should concern us so much as his insistence that art is capable of achieving the loftiest of goals.

We can no more repeat Michelangelo's or Rembrandt's achievements than we can repeat Columbus's discovery of America, or England's victory over the Spanish Armada. What we can do, however, is look within ourselves and within every nook and cranny of our culture for those dimensions of experience and imagination that point toward higher ideals than those that support banality - and then do our very best to give them life, form, and direction.

It won't be easy, but it can be done - even though it will probably mean ''swimming upstream'' against the cultural current, at least for a while, and risk being declared reactionary or irrelevant. Emergence of a gifted artistm

Nothing gives me more pleasure than to announce the arrival of an exceptionally gifted younger artist - especially if he makes that appearance quietly, and without art-world hype of any sort.

Such an event happens rather seldom, but when it does, I feel as elated as an old-time prospector must have felt when he struck gold. My first reaction is to want to meet the artist. My second, to tell the world about what I've found.

That's the way I felt after viewing Alan Magee's exhibition at the Staempfli Gallery here. I walked in feeling a bit jaded, and walked out feeling exhilarated and fresh as a daisy. It's not that I hadn't seen his work before. A few of his drawings had appeared in a 1981 drawing show at the Staempfli Gallery , and I had seen paintings of his in 1980. However, I had never seen an entire exhibition of his work, and so wasn't prepared for what I found.

What I saw were several precisely rendered watercolor drawings of nudes and small inanimate objects. These were quite lovely, although a bit cold and calculated. Even so, they were as good as any other drawings of their kind. They did not, however, begin to compare with his extraordinary larger acrylic paintings of clusters of pebbles, and of the surfaces of boulders.

They are, to put it simply, almost perfect, and are among the best realist paintings being produced anywhere today. They have that aura of authenticity and integrity only found in works in which everything, from the original conception to the execution of the final detail, contributes to the whole. Every single color, shape, line, texture, or movement is related in some meaningful and ''inevitable'' fashion to every other dimension of the painting.

The result is a succession of works whose identities are as clear and as individual as any tree or flower, or any successful painting by the modern or traditional masters.

Viewing these paintings, I had the same feeling of being in the presence of something truly vital that I had had in the mid-1940s standing before the early Abstract-Expressionist canvases of Jackson Pollock and Clyfford Still. In both cases I felt that a page of art history was in the process of being turned.

I don't mean that Magee is turning that page all by himself, nor that he represents anything as crucial or dramatic as what Pollock and Still brought into being. I mean only that he is one of the best of the group currently creating art whose upon premises that have nothing to do with modernism or its ideals. This art is gradually but inexorably establishing itself as an alternative ''voice'' to the dominant two or three modernist voices we have today.

This is pleasing, not because I am in any way antimodern, but because it's time we also accorded full legitimacy to forms of art other than those descended from the seminal modernist movements of the early years of this century.

Alan Magee is one of those whose art establishes that claim to legitimacy. He is an important realist, and one of the first of those for whom the term ''new realist'' has no meaning. There is a starkness and an innocence about his brand of realism that indicates a new beginning, not a modified version of - or a reaction to - something already existing. His best paintings can stand beside the best modernist art produced since World War II, in much the same way that the best of the modernists can stand beside the good art of the past.

This truly excellent show will remain on view at the Staempfli Gallery, 47 East 77th Street, through Nov. 6.