Why should the humanities matter?

Predictable? Of course. That a report by William J. Bennett, chairman of the National Endowment for the Humanities, should make a strong case for upgrading the teaching of the humanities at colleges and universities is hardly surprising. For several decades, faculty members in the humanities - which Bennett, in a working definition, calls ''history, literature, philosophy, and the ideals and practices of the past that have shaped . . . society'' - have suspected that something was gravely amiss. This report, with a few statistics and much lucid discussion, confirms their suspicions.

Predictable, too, is the attention his report has received in the media. For the past several years, Americans have taken educational reform seriously, and this study is but the latest in an impressive string of such reform-oriented reports. And that it should have appeared just after US Education Secretary Terrel Bell announced his resignation - and that Bennett should be a much-discussed candidate for his replacement - has given it added prominence.

Circumstances of timing and subject matter aside, however, this short report is worth reading in its own right - not only by educators, but also by students and parents interested in selecting a university or in defining a course of study once enrolled.

It spells out the problems plainly. It argues solidly, if briefly, that an acquaintance with the great seminal ideas of our civilization, as encountered in the writings of the finest thinkers of the past, is crucial to an understanding of our present and future. It stands squarely on the premise (almost abandoned in the general dismantling of curricula during the past two decades) that, as Bennett says simply, ''some things are more important to know than others.'' And it dismisses the notion that the humanities are somehow elitist - by citing, among other things, the enthusiasm of the undergraduates at Brooklyn College (a public institution, many of whose 14,000 undergraduates are recent immigrants) for the highly structured required courses that make them read, for openers, such knotty classical writers as Sophocles, Aristotle, and Virgil.

Bennett's report, in other words, is a fine first step. Needed, now, is the next and greater step: an extended, philosophical, and eloquent defense of the whole idea of the humanities. Why, after all, should they matter? Why, when students with degrees in business, engineering, and other vocation-oriented areas are thrust into well-paying jobs immediately upon graduation, should one pause to drink at the humanities' deep well? How, in this age, are they relevant?

Such a defense is not properly the job of journalists. As one who spent some years studying and teaching in the humanities, however, I would suggest an approach such a defense might take in considering the question of the relevance of the humanities.

It is widely recognized that students preparing for lives in the 21st century face some mighty challenges. Four of them seem paramount. First, they must be capable of digesting and mastering a glut of information, visual and verbal, that will make today's so-called ''knowledge explosion'' pale in comparison.

Second, they must become increasingly adept in defending their right to think for themselves - in detecting and resisting mental manipulation and the ever more sophisticated means of propaganda, disinformation, and advertising.

Third, they will increasingly be called upon to identify for themselves standards of ethics and morality that will no longer be routinely provided for them by their major social structures.

Fourth, they will need to live, rather than just know, the truths they are defining - to come to grips with the ultimate spiritual goals and purposes of man, in order to cut through the relativism and nihilism of an increasingly techno-centric age and achieve some semblance of contentment and self-worth.

The first two points are matters of process - of knowing how. The last two are matters of content - of knowing what. The humanities, and the humanities alone, can teach both. Furthermore, they can teach them simultaneously, with tremendous satisfaction, and with lasting benefit - if the teachers understand the significance of what they are teaching, and if they themselves stand as examples not of cynicism and sophistry (both of which result from misteaching the humanities) but of the elevating and invigorating relationship between man's humanity and his deeper spiritual aspirations.

On that score, Bennett is right in blaming teachers (''ourselves,'' as he says) for failing to transmit what he calls the ''legacy'' of the humanities. Needed, now, are the great humanists who can provide such soaring justifications of that legacy that our teachers will gladly rededicate themselves to it.