The towers and turrets of Big Dallas seem unreal, a technicolor mirage in the desert. As you approach ReUnion Center, the great green-blue mirrored walls of the Hyatt Regency Hotel loom like the Emerald City. Above the massed building blocks of the main building soars the observation tower. Its crisscross of lights is a fiery, diamond-headed wand working magic against the night.

Not so far away if the new city hall by architect I.M. Pei, who designed the newly opened East Building of the National Gallery. Not the delicately balanced masterpiece his East Building is, the city hall is a massive chunk of a building, with a steeply slanted window wall balancing on a narrow base. Down the street is Thanks Giving Square by Philip Johnson, a wonderful place of flowing water gardens, high and deep spaces, shadows and sunshine, topped with a chapel which spirals upward to the heavens.

Near the spot where President John F.Kennedy was shot is a monument to him, a rectangle with a tall slender, slot for an entrance. One Main Place, a multi-use complex by Skidmore, Owings & Merill, is a massive monument of cast-in-place concrete and riverbed granite snadblasted to make a more textured surface. The Hyatt Regency, by Welton Beckett to Los Angles (where else?), with its one-way view green mirrors, was designed to take the city across what had been the wrong side of the railroad tracks.

In between these tall and small buildings and plazas are lots and lots of parking. The stretches between buildings are so large that one almost feels as though a car is needed to go from one side of the street to the other

Away from the center city are many older wonders. The only theater Frank Lloyd Wright ever designed, a great Paul Cret Art Morderne extravaganza of a fairground and museum complex, and the university of Dallas Campanile by O'Neil Ford (and Duane Landry) are greatly admired. Massive contemporary houses, fanciful chateaus, sprawling ranch houses, acres of fast food factories and few fine Victorian buildings are all entwined with endless miles of throughways which in some cases make it impossible to get from here to there.

Dallas made an appropriate setting almost an outdoor exhibit of today's architecture, for the recent convention of the American Institute of Architects. The AIA is the professional organization, the academy if you will representing more than half of the 50,000-odd registered architects in this country. The theme of the convention was "A time to Learn," and the 4,000 or so architects (and their students, dependents and followers) who came to the meeting took it seriously.

Their speakers told them again and again that the old answers were no longer valid. That the time had come to question everything again - architectural styles, ethics, practices.

Philip Johnson, the cornerstone of the convention, said the meeting "comes at an extroardinary time, a place where we haven't stood for a 100 years, a watershed between the modern style and a new, uncharted uncertainty. Architecture exists in time as well as space."

Johnson was given the AIA's highest honor, a gold medal for a lifetime of brilliant design, as well as the Reynolds Aluminum Co. award (25,000) for his Pennzoil Building in Houston. (He said he had ordered a $30,000 Porshe on the basis of it all). He kept pockets full of buttons with his portrait on them (paid for by the New York AIA chapter) and handed them out to everyone he talked to - which was almost everyone indeed.

Johnson told the assemblage at the Gold Medal dinner that he accepted the medal as a "vote to the art of architecture. I first thought you gave it too me because I was old. I knew half of the previous gold medal winners. But I'm not an insider. Not a goer-to-conventions. As I once said in a peckish mood, I say again in a different way, 'I didn't know you cared.' Now I know you do care about the art of architecture."

To honor Johnson, and by his arrangement, eight architects whose work he likes come to dicuss the State of the Art with him. And architects and students crowded in to the design seminars - many more than in the more mundane sessions such as how to keep from being sued if the roofs leaks, designing solar houses or managing construction.

Johnson told them that the Bauhausaian belief that "more glass will make you a better person," or "flat roofs are moral, pitched roofs are sin" no longer holds. He said that most of the architects he knows have given up saving the world through architecture. For 50 years the pre-fabricated, pre-cast , preformed International Style Utopia had promised all things to all men and women. Now few believe anymore in this promised land.

Instead, Johnson said, there is a real difference in the way not only the architects, but the public, look at things. "There is a regard for symbols. Eliel Saarinen was the first, when he designed Dulles airport in the shape of a bird." Johnson said that today much more attention must be paid to the genius loci the sense of place of artitecture. "I wouldn't design the AT&T building (his controversial projected New York skyscraper with the arched base and the broken-pediment top) for Dallas, because Texas is a postwar state. For Dallas, the Hyatt Regency is right, as a gateway to something grand.

"But New York's great times were the 1890s and the 1920s. It was wonderful to sail and see not just cigar boxes upended, but a true sky-line." New York is conservative, he said, and he felt the AT&T with its extravagant crown (called by wags a Chippendale grandfather clock) is appropriate to the skline. "There is a change today in the way we regard history. The pressure to know history comes not from achitects but from the public. Urban renewal tore down our northern cities. Today, the builder is required to regard the past."

He went on to say that it isn't just architecture that is shifting, but everything. "Is it sunspots, or the energy shortage, or are we just bored? But even the governor of California is talking small. There is new interest in religions, especially the Eastern, the occult, things of the heart, historic symbols, preservation, place. Pluralism is the style. Let a thousand flowers bloom. In my father's house are many mansions."

Several of the design panelists went back time and time again to Thomas Jefferson, and especially his design for the University of Virgina. They spoke of its rightness and its influence on their own work.

Much of the talk at the convention was about how the architects see themselves. Johnson's followers see artitecture as a business, with a product to produced, managed, advertised, insured, lawyered and guaranteed. Most architects wanted to follow both ideas - to be artists and contractors.

The principal nondesign issues concerned changes in the AIA's code of ethics. The membership voted to allow architects to work as contractors - "design/build" they called it - and to advertise. Harold Fleming, chairman of the task force that studied the design/build issue, said the changes would have a "profound effect on the profession."

For some, that would mean the end of the cherished concept of the "gentleman architect," making the practice less a profession and a business. Jerome Cooper, another of the study committee, protested that it is too late for the architect to play the role of master builder.

AIA president Elmer Botsai said that he wouldn't work as contractor for "love or money. I don't have the expertise." But he didn't believe there was necessarily a conflict of interest. "It all depends on how we do it. We mist be above suspicion. Still, most clients come to us for an end product, so a full range of services will help them."

Botsai said the design/build change will make radical differences in the education of architects. "They'll have to learn business skills. Because any architect who runs out tomorrow without education, planning to set up as a contractor will be in a court in a year and deserve tobe."

Botsai said that the rule had been honored more on paper than in practice.

While architects examined their minds, hearts, and pocketbooks looking for a new revelation, most agreed that architecture today was becoming a concern to more than just the profession. John Burgee, Johnson's partner, said they had received several hundred letters about the AT&T building. In Miami, there is a general uproar about a Spanish-spiced building the two have designed. Preservation societies are active everywhere, and indeed a number of honor awards for design this year went to remodeled ("extented use") structures, including the Elliot house in Chevy chase, designed by Hugh NewellJacobsen.

Johnson said he hoped the days would come again when a president, as did Jefferson, would take time off from the cares of state to design a university. In the same vein, he recalled the story from the Middle Ages in which a mason, placing a brick improperly, was laughed off his ladder by the people in the street