When our mothers sang to us

One of the most typical and dependable traits of modern Western culture has been adulating the very old and the very new while anathematizing the work of the generation immediately before.

America has been no different, musically, with its postwar attitude toward the mature native voice that rose up during the 1930s and '40s and demonstrated clearly, for the first time, that American composers were capable of first- and world-class musical works free from the slavish beholdenment to Europe of previous generations.

This voice was hushed considerably, following World War II, by a return of philosophies and credos from across the Atlantic, negating the naturally expressive elements that had risen to the surface in the music of composers like William Schuman or Virgil Thomson or - most particularly - the late Samuel Barber.

Few composers in any time or place have achieved as fine a musical blend of head and heart as did Barber, whose music is uncommonly consistent in its craftsmanship, economy of statement, and deeply moving emotional charge. And few pieces present such a capsule image of Barber's music as does ''Knoxville: Summer of 1915,'' a setting for voice and chamber orchestra of a text by James Agee (portions of which are reprinted on this page).

Cast in the form of one long aria - actually in four distinct musical sections - Barber's ''Knoxville'' is typical of his consummate understanding of composing for the voice, of poetics, prosody, line, and the balance with instruments. Setting prose to music is particularly difficult, but Barber has used Agee's text to good effect, masterfully emphasizing the parlando aspect while retaining a lovely melodic arch. He takes the childlike impressions of Agee's fragmentary monologue and filters them through the depth of adult experience. He does not set to music, but inscribes above the score's beginning, his clue for doing this - Agee's opening line, with the phrase ''. . . so successfully disguised to myself as a child.''

Barber's 14-minute evocation of a child's impressions of life-before-speech does contain the kind of aching nostalgia that many have found fault with in Barber's music over the years. But it is also typical of an original but timeless sense of sonic beauty that seems to have slipped from our grasp in modern times.

We see today a yearning in so many places (and guises) for a simpler, purer outlook on life. Barber's music and Agee's nostalgic text may be a marriage of sentiments not wholly to the liking of those who criticize the ruminative element in ''conservative'' art, and who mistrust looking back for its own sake - and they are right regarding the latter. But the formal coherence and utter artistic adroitness of Barber's achievement here, and in his other works, will not go away, any more than musical art's abiding identity as an aural thing - above and beyond cliques, dogmas, and trends - can be obliterated.

Style is the servant of propulsive musical statements, not their arbiter. It is, as Virgil Thomson long ago put it, inspiration channeled through a particular point of view. ''What does it sound like?'' will be the question history uses in deciding which music to return to and which to drop. We progress - we keep our bearings and perspective, at least, in this tumultuous world - when our inspiration and our point of view can coalesce and our music can retain some kind of connection with what went on . . . when our mothers sang to us.

Samuel Barber: a listening list.

* Violin Concerto (1941).

* Piano Concerto (1962).

* Essays Nos. 1, 2, and 3 for orchestra.

* Symphonies 1 and 2.

* ''Three Reincarnations'' (a cappella chorus).

* ''Dover Beach,'' for baritone and string quartet.