When the Kimbell Art Museum opened its doors in October 1972, it was instantly recognized as an architectural masterpiece, a shining example of late modernist architecture at its most elegant and inviting. Indeed, the Fort Worth, Texas, museum was soon hailed as a curatorial masterpiece as well, so magnificently had Richard Brown, the Kimbell’s founding director, realized his ambition of assembling a small collection of art works “of the highest possible aesthetic quality.”

Emphasis must be placed on the word “small.” Mr. Brown—who served as the museum’s director until his death in 1979— understood from the moment plans for the museum began to unfold that the Kimbell’s claim to distinction would have to be based on quality, not quantity. And he had understood that for the museum to succeed as he wished, the aesthetic perfection sought for the collection must also be sought for the building erected to house the collection. As he wrote in a pre-architectural statement of June 1966, “a building with such an organic integrity cannot be built in stages, with allowances and adjustments being made for future wings, extensions or added floors. The form of a building should be so complete in its beauty that additions would spoil its form.”

Given this aspiration, Mr. Brown would seem to have been exceedingly fortunate in his choice of Louis I. Kahn (who died in 1974) as the architect for the Kimbell. The museum has less than twenty-thousand square feet of exhibition space, yet we can think of no other recent building—certainly no other recent museum building—to which the term “perfect” has been so frequently applied. “Perfect” derives from the Latin word meaning “finished” or “complete”; and so, despite its modest size, the Kimbell had seemed to almost everyone—at least until last summer, when the museum announced plans to add fourteen-thousand-foot galleries to the north and south ends of Kahn’s building.

The spate of recent plans for museum-raping in this country—those of the Whitney Museum of American Art and the Solomon R. Guggenheim Museum are only the most notorious cases—has made the response to the Kimbell’s announcement a familiar litany. There has been the usual outcry from architects, critics, and preservationists; then we have witnessed a stream of elaborate rationales from Edmund P. Pillsbury, the museum’s director since 1980, and Romaldo Giurgola, the Australian-based architect commissioned to draw up the plans to expand the museum; and of course we have watched Paul Goldberger, the chief writer on architecture for The New York Times, come down on every side of the controversy.

The most recent episode in the debate over the Kimbell took place on January 22, when Messrs. Pillsbury and Giurgola came to plead their case at a crowded and sometimes contentious meeting organized by the Architectural League of New York at the McGraw-Hill auditorium in New York City. Once again, the argument was familiar: the museum did not have enough space. There was not enough space for parking, for eating, for book buying, for educational activities; there was not enough space to keep the permanent collection on view when temporary exhibitions (of which there have been a steadily increasing number at the Kimbell) were mounted.

This last item was obviously the most pressing one, for it is largely by mounting ever grander travelling exhibitions that many ambitious museums seek to gain visibility and distinguish themselves in the public eye today. As it happens, the exhibitions the Kimbell has mounted have been popular and of a consistently exalted quality. But the question is whether the desire for expansion, for greater prominence and media visibility, justifies maiming an acknowledged architectural masterpiece.

Admittedly, Messrs. Pillsbury and Giurgola had a difficult, perhaps an impossible, task. Knowing the reverence in which Kahn’s building is held, they had to repeat over and over again that they, too, thought it was a marvelous building, that it possessed “organic unity,” in short, that it was perfect. And yet they had to convince the audience that one could almost double the size of the building without compromising its perfection. Mr. Giurgola—an associate of Kahn’s in the 1950s and 1960s—aimed to minimize the outrage by mimicking the master, more or less duplicating Kahn’s distinctive cycloid vaults in his design for the addition.

But how can one change something so drastically and have it remain the same? During the question period at that meeting in New York, Sue Ann Kahn, the architect’s daughter, rose from the audience to declare that Mr. Giurgola’s plan looked like “a shopping mall with an underground parking garage” and to warn that “if this proposal were to be carried out, we would never be able to see the building again.” Mr. Pillsbury responded with some pique that “the last thing” Louis Kahn would have wanted would be for us to treat his museum as “a bourgeois artifact.” We fear that Mr. Pillsbury did not really answer Miss Kahn’s objections. A “bourgeois artifact”? Well, yes, we suppose it is. But what sort of artifact, exactly, does the distinguished Mr. Pillsbury believe himself the director of?