Television keeps getting better and better. At least this is the impression left by "TV: The Casual Art," in which the dramas of TV's so-called "Golden Age" are debunked while the splendors of "Baretta" are bunked.

The proponent of these audacious opinions is Martin Williams, who is best known to Washingtonians as the Smithsonian Institution's jazz impresario. He put together the Smithsonian Collection of Classic Jazz albums, among other credits. In a previous existence Williams was a TV critic, contributing a television column to The Village Voice from 1961 to 1964. A group of his Voice columns forms the core of "TV: The Casual Art," supplemented by fresh footnotes and by some additional essays about television that Williams has written over the years.

Because Williams was only sporadically a TV critic, the chronology of his commentary is full of holes. His book's scope is also limited by a point of view that considers TV almost totally in terms of the esthetic quality of its regular prime-time and Saturday-morning fare. Williams virtually ignores the role of TV as an instrument for selling, baby-sitting, watching sports or old movies, or doing a myriad of the other tasks that are now assigned to it.

However, despite the book's fragmentary nature, several refrains occur repeatedly enough that they become loud choruses. Most of them are either songs of praise for the unassuming or jeers of disdain for the pretentious.

Williams has kept the populist faith throughout the decades. He dismisses most of the Golden Age dramas as pallid, formula-bound imitations of the plays that were then in vogue on the Broadway stage. His idea of good television drama is "Gunsmoke" or "Naked City" or -- in some ways even better -- "Kojak" and "Baretta." He sticks a pin in the reputation of the Golden Age's Sid Caesar, preferring the likes of such clowns as Lucy, Skelton, Van Dyke and, yes, "Laverne and Shirley."

Television news has yet to impress Williams, and he ridicules the notion that more time for news equals better television: "We have produced a whole class in American society to whom any kind of news report or factual document . . . is intrinsically more important than any kind of drama or fiction -- to whom, presumably, a knowledge of the fact that the 'historical' Jesus would actually have been born in 3 A.D. is more important than a feeling for the parable of the Prodigal Son."

Naturally, public television hardly stands a chance with Williams, who says, "Sometimes I think those who insist on doing Something Good on Television are the worst of all." The best programs on public TV, he says, are "those that have learned, and learned well, the implicit lessons that commercial TV, with its far more experimental nature, has to teach. And the lessons are: keep it brief, keep it direct, keep changing the subject . . . and keep changing the scenes or the setting."

When the specter of television as a social force rears its head, Williams can be maddeningly glib. He believes children's television is bland and hypocritical since its level of violence was reduced. Besides, he tells those nervous nellies who worry about excessive video violence, wasn't "Hamlet" full of gore, too? In fact, all too often he defends the tube by pointing to other media, as in this from 1964: "I don't feel disposed to demand much more of the media. Has Broadway or the movies offered as much?" Critics should not settle so easily.

Those words and other evidence presented by Williams do serve to remind us that early-'60s TV was not a total wasteland. In this and in some of Williams' zingers aimed at anti-TV snobs and improve-TV-by-fiat crusaders, "TV: The Casual Art" is at its most interesting.

Generally, though, Williams carries partisanship too far. In one curious footnote written recently, he chides academicians in the field of "popular culture" who "find equal interest in Mickey Spillane and Dashiell Hammett; Roger Corman and John Ford; Cher Bono and Sarah Vaughan; Norman Rockwell and E.C. Segar; 'Bonanza' and 'Gunsmoke' " and thereby "avoid the task of sifting and evaluating the work of our most original artists." Yet in the next paragraph, Williams repeats his previously stated admiration for "the inspired whimsical zaniness" of "Green Acres" and for "the incredible gradations of feeling that flow through Dean Martin's very presence on the small screen." Elsewhere he twice salutes the wondrous Efrem Zimbalist Jr. and cites "Hawaii Five-O" for "the most consistently good suspense scripts ever."

Some more rigorous sifting would have been useful here. In the meantime, those of us who would rather watch Cher than Dean Martin must face the awful truth of our philistinism and pledge to uplift our humble tastes.