It has been a while since a Washington museum had the effrontery - or courage - to try to show us what the newest new are looks like. The Hirshhorn Museum and Schlupture Garden, where the group of group shows called "Directions" goes on view today, has tried to do just that.

No single exhibition can begin to encompass the art of the pluralistic 70s. Everybody knows that. To select 18 artists from the many thousands - as Hirshhorn curator Howard N. Fox has done - implies arrogance. To pick just five "directions" from the many being followed suggests narrow-mindedness. The voids in such a show ought to overwhelm its virtues; Fox's exhibition ought to be a failure. But it isn't. It's a treat.

Fox is on to something. He sees that after many years of minimizing - of careful cautious cleansing - the art made in America is filling up again. His "Directions" show is crowded with popsicles and penguins, pieties and puns, with eye games, mind games, fictions. It is also full of fun.

Much art of the '60s seemed to tell the viewer, "Ignore your store of memories, make your mind a blank, look at me alone." The objects on display here are not like that at all. If you do not know about Wonder Bread and Fred Astaire, disaster movies, mouse traps, Manhattan subways, Midwestern tourist cabins, Pompeii, saints and sinners, you will not understand this show.

It is less spartan than playful, less reductive than additive, less concerned with leaping towards the future than summoning the past. Some of it is beautiful, some of it is crass, but all of it demands that the viewer think, imagine, and remember. This work is not content to live in the white-walled world of art. It spills out into life.

This art does not discard the hardwon purities of the '60s. It builds on them instead. Daring artists once arranged bricks on the floor. Loren Madsen has taken 514 heavy bricks and has set them, very beautifully, hovering in air. He uses stainless-steel wire, specially reinforced walls and tedium to do it. His geometries are pure, but his art is not minimal at all.

Nor is the work of his fellow sculptors John Van Alstine and George Kuehn. Using concrete, rough stone and steel chains, they make art that doesn't just sit there. Their sculptures suggest work and poise, restraint and tension. Fox calls them "brute sculptures" - one of the five converging directions he points out in his show.

"Imitations" are another. They tease the viewer's mind as they trick his eye. Those porous slices of white bread with their thumb indentations carved, and nicely, too, by Jud Nelson out of marble. Alan Kessler's used and rusted metal tools - his hammers, trowels and screwdrivers - are not what they seem. They are made of balsa wood that Kessler carved, then painted.

Peter Saari's seemingly antique rusted spearpoints, like his badly damaged frescoes from Syracuse or Pompeii, turn out to be not ancient artifiacts, but subtle canvas paintings. They are lovely and amusing. Marble sculpture brings to mind Praxitiles, not Wonder Bread; ruined frescoes conjure the reflexive awe we feel before antiquity, not cunning modern artifice. Before these "imitations," these intentionally "false" objects, the mind begins to spin.

There are four purer painters in this show. Fox feels they follow a direction he has labeled "Eclectic Surfaces." No such label saves Kim MacConnel's strips of painted cloth from their look of garish tackiness, nor does it lend much interest to Robert Hudson's nicely composed borrowings. Barbara Rossi's pictures, with their blend of East Coast formalism and bizarre Chicago imagery, need no apologia. Even more beautiful are the paintings of David Schirm, with their ferns and fronds and fish-like shapes, and their wondrous colors. He and Madsen are the two most memorable artists from the "Directions" show.

The "Fictions" section here is the most disappointing. Dottie Attie's little drawings - almost all are quotes from Leonardo, Stubbs and other masters - are pleasing pictures, and the stories that she tells by putting them in sequence are pleasingly perverse.But Steve Gianakos' black ink drawings on How to Murder Your Pets are not really more than sleek cartoons, sophisticated stabs at black, or perhaps gray, humor. Roland Reiss makes little 3-D scenes of schoolrooms and dance studios in which every prop - the Tophats and the French fries, the cigarettes and slippers - contribute to a story that would reward contemplation if Eleanor Antin's blaring TV movie would allow the viewer a bit of quiet. Antin is an admirable artist, but her noisy work here blights the show.

The exhibit ends with "Shrines," of which those of Thomas Lanigan-Smith and Donna Dennis are the most impressive. Lanigan-Smith believes in God, and in the Devil, too. The icons and the rats he makes of tinfoil, plastic wrap and sequins, although they flirt with kitsch, are sufficiently convincing to make the viewer believe that Lanigan-Smith wholeheartedly believes.

Donna Dennis' subway entrance, her cabin and her Midwestern house, would look like borrowings from Real Life were they not about a third too small. Standing before them, the observer feels himself to be somehow huge, omnipotent - as if he is exploring not an art show, but his dreams.

Not so many years ago, new art seemed to be busy casting off all but the essential. The new art on display here seems instead to welcome story, illusion, struggle, wit, dream and magic - all the resources that artists used to use. This exhibition shows us that they are using it agin. Fox is only 32. Perhaps only a young curator would have the enthusiasm and the freshness to organize this fresh and heartfelt show. It closes Sept. 3. CAPTION: Picture, Judd Nelson's marble popsicles at the Hirshhorn's "Directions" show