This week, Congress will convene the first in a series of hearings on the budgets of the National Endowment for the Arts and the National Endowment for the Humanities.

The uncertain future of the endowments has become a controversial issue since last fall, when the Reagan administration called for a 50-percent reduction in each agency's funding requests for fiscal year 1982.

Since their creation in 1965, the endowments have enjoyed continued financial growth and program expansion. By fiscal 1981, the NEA annual budget had reached $158 million, and President Carter proposed increasing the figure to $175 million for the coming year. For the NEH, he proposed raising the current $152 million to $169 million.

But when Reagan's Office of Management and Budget submitted its plan to reduce federal spending, the endowments were targeted for substantial cuts in fiscal 1982 and spending limits of $100 million beginning in 1984. That proposal outraged supporters of the endowments and satisfied detractors, including some at the conservative Heritage Foundation, which had charged the agencies with political bias in awarding grants -- among other purported shortcomings -- in a study prepared last fall for the incoming Reagan administration.

The opinions below represent both sides of the endowment debate. To simplify issues, the argument is limited to the National Endowment for the Arts.

Defending the NEA is Toni Morrison, whose "Song of Solomon" won the 1977 National Book Critics Circle award for fiction. A senior editor at Random House and a member of the National ycouncil on the Arts (the advisory body of the NEA), her lastest novel, "Tar Baby," was published this month.

Tom Bethell, a Wasington editor of Harper's, Washington correspondent for The American Spectator and author of the 1977 book, "George Lewis: A Jazzman From New Orleans," argues that the NEA should be abolished.

DEADLIER THAN the brutal budget cut that the Office of Management and Budget has recommended for the National Endowment for the Arts is the glee with which it has been received in certain quarters. "Exciting," chirped a journalist on a TV news panel; "sensible," whispered the New York Times editorials; "it can't hurt us," a young professor told me, referring to his private college, "and the endowment could stand some belt-tightening -- we all could."

Those of us outraged by the idea of reduction in endowment funds are put in the position of willful children pouting because our meringues are being withheld. Against belt-tightening in a time of crisis? And for the arts, of all things? The whole country has been ordered to go on a diet -- and at the end it will be lean and beautiful, the way it was 40 years ao. "Excess" and "fat" are the terms most frequently used. This carefully chosen recisionist vocabulary has accomplished its aims: Belt-tightening is made to appear not only patriotic, not only healthy, but as positively adult behavior. It urges an eagerness for discipline and stoicism among the truly grown up and, at the least, a quiet accommodation among the less mature.

But the response elicited by the diet glossary is not adult. It is foolish and uninformed and can be taken seriously only by those who are gratified by the froth of an idea and indifferent to meaning -- those whose assumption is that belt-tightening necessarily involves the waist, which can never be too thin. They seem not to be aware that it can also involve the throat.

What the OMB proposes for the NEA - a 50-percent cut in the Fiscal 1982 budget of $175 million requested by the Carter administration -- is a simple, deft strangulation. A tight monetary strap pulled and buckled around the neck to cut off the air it needs to stay alive. Make no mistake: A 50-percent reduction will strangle the endowment and the accompanying $100-million limit for the future will bury it. That grave consequence is quickly revealed as soon as one gets past the slippery vocabulary to examine the reasoning that produced it.

The reasons given by OMB in support of the cuts are based on shabby scholarship, inaccurate data and an astonishing ignorance of the workings of the NEA itself. Consider them, shall we, one by one.

Government support for the arts dries up private and corporate funding . Nothing could be further from the truth. Ten years ago non-government funding for the arts was at an annual level of $230 million. Now, as a direct result of the manner in which NEA grants are given, the level reached $3 billion during the past fiscal year. Matching-funds provisions generate private giving; and direct grants reassure potential donors about the long-term solvency of institutions, encouraging more giving. In these and other ways, the "leverage ability" of the NEA produces more corporate and private funds for arts -- not less. The NEA does not act as a substitute for such monies; indeed, without the endowment mechanism, such funding would indeed dry up.

In the absence of government financial support, there is nothing for the arts committees to fear because corporations will and can take up the slack. Financial experts are already warning that, in a sluggish economy, the corporate world cannot bear that burden and will not assume it. Even those corporations able and eager to continue funding will be prevented from doing it because their evised tax structure will make it far more advantageous to invest their profits than to donate them. Without the presence of the NEA and its leverage systems, there will be no incentive for corporate support. In addition, the history of private funding has shown that when the government takes the lead in its endorsement of the arts, the corporations follow suit. When the administration shows its contempt, the business community is quick to get the message.

The recommended cut will help fight inflation. For economist to imagine that trimming one half of the NEA's budget (the reduction would amount to about one-tenth of one percent of the projected federal deficit for Fiscal 1982) can affect the inflation rate by one jot is a flight of optimism more sweet than sound. But it is worse than fantasy: It is wrong-headed and counter-productive for fiscal experts to ignore the fact that this ant-sized budget ($158 million in Fiscal 1981) actually carries 18 times its weight in the additional monies it culls from non-government sources. Every 5 cents spent by NEA deliveres $1 in corporate and private money. To recommend the disintegration of an agency with that power and record of achievement does not encourage confidence in the sanity of the Reagan administration.

OMB works for an administration that is rumored to be vitally concerned with economic stability. Yet it recommends crippling an agency that makes it possible for its artists (whose unemployment rate is near 50 percent) to work, individually or by association with art institutions, and earn money which keeps them off the welfare roles, keeps them away from food-stamp lines and presumably out of the class of the "truly needy." OMB works for an administration said to be concerned about the debt and decay of cities. Yet it recommends the disabling of an agency which, by supporting art audiences and institutions, produces billions of dollars in income for cities and towns through taxes, tourism and attendant revenues from crowds. It does not take a giant intellect to discover that NEA grant-giving does not contribute to inflation -- it fights it.

The direction of NEA is toward developing art for social purposes rather than artistic ones -- too much of its growth is in the area of art for political purposes . This is an ill-researched idea that was once merely amusing to hear statesmen repeat. One always knew what academicians meant by "real" art vs. "political" art (any art that espoused politics not their own). The arts establishment has been depoliticizing its favorite artists for generations. There is, of course, an esthetic of art for art's sake. But it is not a fixed star nor a law of physics. It is simply one way of evaluating art forms. But even if it were the only way (rather than a theory less than 80 years old), the fact remains that questioning the origin or class or sex or race of an artist or an art constituency applying for a grant is in itself a prescriptive and oppressive political act.

Those who scream "politics in art, alack, alas" are themselves imposing political restraints on the art community. If the question of the "place" of politics in art is to be taken seriously, it should be consistently applied. oNot only would ethnic, aged, institutionalized and working-class audiences and artists be singled out for investigation and the budgetary whip. We would have to cut those who play Wagnerian music. We should scrap funds for performances of plays by that social reformer George Bernard Shaw and reject support for the hanging of a Picasso show. We should investigate the working-class sympathies of Dos Picasso, the regionalism of Faulkner, the politics of Dante, Aristophanes, Dreiser, Thoreau, Emerson. We would deny access to the lovers of that great mental patient Vincent Van Gogh, not to speak of Ezra Pound and every dissident artist in the country.

All of these represent some political posture, origin, disadvantage or association with groups identified specifically, and by innuendo, as "political" (and hence not artistic) in the current thinking of the Heritage Foundation, the conservative think-tank which has recommended gutting the arts and humanities endowments. No one contemplates such an investigation (not now anyway) and no one should, because it is silly. And if it is silly to refuse support for a symphony orchestra that has Wagner on its program because the composer was a racist, then it is equally simple-minded to do it in the '80s for contemporary artists whose value and future stature the OMB cannot possibly know.

These political attacks upon art groups for being political hide behind the plea for "quality" as the only criterion for grant-giving. The term is bandied about as though it has been defined in perpetuity by the art establishment, or as if the endowment were accustomed to subsidizing mediocrity. The NEA panel's criterion has always been, "Is it any good?", and since everybody cannot know the quality of every form, review and recommendation are performed by a panel of peers who do know. The NEA insists that the cultural esthetics of an art form are to be judged by people who know something about that culture, just as it insists that the esthetics of the majority culture be attested to by those familiar with its standards. It does not presume to judge the excellence of Scott Joplin by the guidelines of Medieval part-song.

"Excellence," "quality," "non-political" -- that lexicon, as it is used by those who have provided reasons for the death of the NEA, is designed to support safe art, artists and art institutions. It is a way of saying "to support art, artists and art institutions because they are black, Hispanic, laboring people, women and so on is political. But supporting art, artists and art organizations because they are not black, Hispanic, feminists and so on is art."

The monetary attack on the NEA is fiscally irresponsible and intellectually daft, but there is something much more disturbing in the assumptions out of which this spacious reasoning comes. Let me try to explain the overwhelming disquiet and unease I feel.

In 1937 the chancellor of Germany dedicated a new museum, and in his speech alluding to the fine patriotic qualities of the artists housed therein, he used an extraordinary expression to describe the artists who should be excluded from government support. He called them "art criminals." I have never read or heard this phrase anywhere else, but the idea of such a category is very much alive.

It is alive in the suggestion that art is frill. It is alive in the suggestion that art with social purpose should not be in the purview of government funding. It implies that the artist is illegal if his origins vary from some patriotic norm or if his work does. It says that a painting or a song can be against the law. And there are many nations who act on this concept of the art criminal -- so much so that one can judge the quality of a nation's art by the number of its practitioners who have fled. It is pernicious and suicidal for any hint of that idea to become entrenched in the thinking of this country.

President Reagan has stated that the government should not be used "to bring about social change" -- meaning, apparently that the government role is to curtail social change. Therfore, when the government strangles the art community, it is saying to its own citizens: Your government has no interest in a future, only in a past. It is saying to that part of the public that can least afford it -- to struggling artists and art organizations that have absolutely no access to corporate funds: You must wither while these other flourish. It is saying to poor people in Tucson, the Bronx and Oakland: You must not only live in substandard housing, with poor health care, inadequate protection and subsistence diets, you must also relinquish your cultural life-line -- the reason, sometimes, you get up in the mornings; the respite you look forward to of an afternoon; the relish of working at your own art. That, too, you must live without, even though it may be the single creative, constructive and joyful thing you do.