"Get me my blue soap box, please. I want to make a speech," sings Moss Hart's Liza Elliott in "Lady in the Dark."

"If you want to send a message," remarked George S. Kaufman in another connection, "try Western Union."

These were typically American distrusts about the didactic as a dramatic force. This quality - "having the character or manner of a teacher" - is, however, treasured by high-minded dramatic critics. It accounts for their particular venerations, among them of Brecht, who should be venerated for other reasons (character-drawing), and numerous others who promise dramatics, then bang us over the head with the obvious.

Some consider Shaw the most didactic of all playwrights, but his plays refute the notion. Shaw spent most of his 90 years on sopaboxes of all colors but was meticulously careful to confine his didacticism to his prefaces. These brilliant essays illuminate but do not sink his plays, not even the marvellous long speeches in such works as "Saint Joan," "Major Barbara" or "The Millionairess." Shaw created vivid characters and imaginative situations but he did not lecture us directly himself.He used his characters and, of course, they often sounded like him. But he was indirect.

By chance our two resident playhouses begin their season with British imports that, in other hands, might have been laboriously didiactic. But they most carefully are not.

"Whose Life Is It Anyway?" at the Folger is Brian Clark's current London success. The Louisville Actors Theater shares with the Folger Theater Group the first American performance rights. Later this winter there will be a third production for Broadway.

"Tales from the Vienna Woods" at Arena Stage is Odon von Horvath's 1931 drama introduced last year by Britain's National Theater. Christopher Hampton's is the first English translation of any Horvath play, and Yale concurrently is presenting its own production. Do not look for a commercial theater version. Too expensive.

Clark's play is surprising for its wit and zest, surprising because the deeply serious situation might have inspired a didactic style.

After an auto accident, a sculptor is paralyzed from the neck down. Hospital, doctors and machines are devoted to keeping the body alive. But the artist's mind is sharp. His perception of his future is that he will become a vegetable. He wants the machines removed so he can be freed from such a fate. He wants the law to free him.

Sculptor Ken is an amusing, life-relishing man, speaking only for his personal stance. Clark allows those who oppose him their personal dignity. Setting the case, he urges us to think along with Ken, even to disagree with him.

Clark's approach to what superficially might seem depressing material is rooted in thre words: "Less is more."

Initially a drama teacher, 38-year-old Clark discussed what his switch from teaching to creating had meant to him. He quoted Michelangelo, chipping stone away to reveal statues: "The more the marble wastes, the more the statue grows." He noted a French painter's basic advice: "Learn to draw. There's nothing in it to prevent you from becoming a genius."

Teleplays gave Clark his first chance to earn a living as a writer:

"I feel sorry for American writers," he mused. "Instead of encouraging quality for TV, sponsors, agents, networks all seem to settle for the lowest common denominator. There's no sense of subtlety or indirection. Our television, both BBC and ITV, actively seeks out quality writing, intelligent ideas. For potential dramatists, your TV is a writer's wasteland."

With this, his first stage success now into its seventh West End month and no end in sight, Clark is cheered by promise of the future. His play has led to his own production company, including the actor (Peter Barkworth), producer and director who worked with him on "Whose Life Is It Anyway?" After attending the Folger opening, he's already back in England to finish the 10th and final episode of "Telford's Charge," which will begin its British network airing in January. After that it's a return to America for the play's Broadway production.

"No, I don't mean the play to be didactic in any way. I'm not telling anyone what to think. I am simply presenting a situation and asking questions about it, a particular man, what a particular situation means to him.

"I've found that to say less is to achieve more. It's rather like acting itself. The elss the actor does, the more he cuts away, the more accurately he narrows in to the point. Didacticism bulges, gets fat. No, I'm not teaching. I hope I'm asking questions in interesting, theatrical terms."

Sepctacularly staged, Horvath's Arena drama concerns middle-class Vienna a decade after World War I. He is dealing with losers in what he called "the gigantic battle between the individual and society."

"It was a time very like our own," said director David Chambers, "inflation, governmental pressures on the individual."

Translator Hampton's studies prompted him to note: "Horvath, unlike Brecht, was not a didactic writer, asking on the one hand for a cool, detached audience and, on the other hand, presenting them with an open-and-shut case. Indeed, if you look at the earlier drafts and scenes eventually not included in 'Tales from the Vienna Woods,' it is clear that Horvath drew back from anything that might seemt too crudely over-simplified . . . Only the liveliness and compassion with which each individual character, even the most reprehenseive, is drawn, show where Horvath's sympathies lay."

And so, in the parade of 35 Arena players, some of them doubling, we are guided to note the humanity of each, major figure or cameo. These characters are not outsize, like Brecht's, or cardboard cliches. Each, even the blind piano-playing countess, is richly individualized in writing and performance.

In Arena's vitality-charged production, I found not the lurid slants of Brecht, whose true gift lay in such characterizations as Azdak and Mother Courage, nor even the scintillating theatricality of "Cabaret," which was at great remove from its source, Christopher Isherwood's cool "Berlin Stories."

In "Tales from the Vienna Woods" I find ordinary people afflicted by atmostphere, a climate which ultimately spreads.

Both these are thinking plays but pointedly avoid the dead weight of didacticism.