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The Rational School in mid-nineteenth century was an amorphous body of architects who held that architecture was ornamented construction, essentially structural form, however refined or adorned. Found in the philosophy that reason is the source and test of knowledge and best served by deductive inquiry, and as an extension of the Enlightenment, it was French in tradition as bequeathed by master masons of the socalled Middle Ages. It was differentiated from the British empirical tradition that ultimately was popularized as the picturesque, a distinction to exist well into the 20th century. Yet French and German architects consistently applied the theory to classical buildings; an early epitome was J.G. Soufflot’s Church of St. Geneviève (Pantheon), Paris, 1757, a building to lead into Romantic Classicism. Academic design rituals were then perpetuated by the École des Beaux-Arts, Paris, followed by its many imitators in North America 1890–1940.

But the École had devolved to classique formalism, much to the chagrin of committed rationalists such as Jean-Baptiste Rondolet, who in 1802 argued that architecture derives from construction and is not an imaginative art. Or those impressed by the influential books of J.N.L.Durand, Rondolet’s contemporary. Proposing that architecture be conditioned—as his fellow revolutionaries insisted—by social demand, that style be the “visible expression of its functioning parts,” axial symmetry and classical forms in simple geometry were Durand’s aesthetic preferences. As a planning methodology, he used a square grid to order structure and explain plan. It was a type of orderliness that post-1850 attracted theorist and architect E.E.Viollet-le-Duc. But Durand’s obsession was French Gothic with its constructional clarity of parts, not just expressed but plainly exposed. His written expositions on modernism (that is, speculation as to an appropriate architecture for his day), on the use of new materials and technologies, on reasoned “principles, as opposed to rules” or imitative forms, on buildings as organisms, on style rather than the styles, and so on, remains highly persuasive.

Traditionally, the architecture of rationalism tended toward classicism, thereby emphasizing its foundation in 18th-century mathematics (measurable truth), therefore geometry plays a significant role. More lately this can be seen, for instance, in the early works of Frank Lloyd Wright, those post-1937 by a disciplined Ludwig Mies van der Rohe, and those beginning in the 1960s by Louis I.Kahn and his intelligent follower Mario Botta. From their individualistic variety we also can see that there is no coherent rationalistic style.

It is generally held that Rationalism arrived in the United States c. 1800 through French emigrant architects such as Joseph J.Ramèe, Maximilian Godefroy, and Benjamin H.Latrobe. But it was swamped by Jeffersonian Romanticism and formalism. The counter was found first in the words of Ralph Waldo Emerson and then in the might of industrialization and concomitant technical and engineering developments.

Emersonian nature and utility and inspired sculptor Horatio Greenough, who praised monumental buildings that addressed the “sympathies, the faith, or the taste of a people.” He wrote Emerson that architecture was: “A scientific arrangement of spaces and forms to functions and to sit,…features proportioned to their graduated importance in function.” The expression of functionality was the demonstration of reason. (The philosopher, whose tool is words, would refer to positivism.) Borrowing from American architect Louis Sullivan, who drew from Kant, Emerson, Greenough, and others, Wright was inspired by the “form follows function” aphorism, extending it by reflection on his family’s love of Emerson, who urged a link with those “pertinent object lessons nature so readily furnishes,” as Wright said. Is there anything in nature that does not function correctly, wondrously? Rationalism easily becomes entangled with the notion of utility and nearly synonymous with functionalism. But nature was the perfect teacher.

The application of rationalism reached a practical epitome beginning in the 1880s with the frighteningly tall buildings in New York City and Chicago. They had adopted structural systems evolved by engineers and building contractors and contained utilitarian features and technical innovations within a variety of facades. The expression of stacked spaces (to the Romantic), of stacked floors (to the rationalist), and vertical systems (water, people, structure, waste, etc.) was—and is—the architectural problem.

Although many were inspired by Viollet-le-Duc’s words Wright made them contemporary and vital by speaking of an organic architecture for America’s modern society and by producing works of an articulated (functional) clarity. The demonstration is the Darwin Martin house of 1904–05, and the Larkin Administration building (1903– 06), both in Buffalo and both a rationalist’s paradigm for differing building types.

Many of Wright’s buildings possessed what he referred to as “picturesque” characteristics as he interpreted them from the English Arts and Crafts movement. His persuasion had a marked influence on European theory post-1910. Thus Wright and many of those founding modernists who were inspired by his words (not necessarily by his romantic designs), such as Walter Gropius, Le Corbusier, even Louis Sullivan (from whom Wright had drawn much nationalistic and transcendentalist fervor), and by Albert Kahn’s industrial architecture, extracted intellectual sustenance from 19th-century theory and speculation.

In 1902 Sullivan wanted to impress on his audience “the simple truth—immeasurable in power of expansion—of the subjective possibilities of objective things.” The architect’s role was to interpret those things. In Europe Hendrik P.Berlage wrote about the “pure art of utility” and believed his Amsterdam Exchange buildings (1897–1903) followed principles espoused by Viollet-le-Duc. Auguste Perret was perhaps France’s most ardent classical rationalist so dramatically expressed in concrete structures and axial symmetry from 1903–25; consider Notre-Dame Le Raincy (1922–24). Up to the 1960s Le Corbusier was France’s most versatile structural rationalist, as a comparison of Monzie house, Garches (1927), and the monastery of Le Tourette, Lyon (1957–60) patently reveal. Yet his three-dimensional compositions are also picturesque in manners that baffle rigid theorists.

When in the 1920s the central Europeans, in particular the Germans, absorbed the visual aspects of the rationalism inherent in Albert Kahn’s industrial architecture (where primary considerations were daylight, production process, functionality, money, construction time, and structure), they elected for a reductive, chaste, plain interior and exterior aesthetic constructed in glass, concrete, or steel, usually exposed. Wright and others (such as the Dutch) worried that such an architecture might lead to a rejection of its traditional role as a social art to become merely utilitarian, rationalized rather than rational. In the 1920s the Modern movement was driven by rationalism until its industrial style was found to be a useful expression for internationalism as promoted by the political left. Mies van der Rohe in the 1920s, for example, took much from Wright (and others) to generate a dynamic architecture based on American industrial buildings. By the late 1930s he settled for what is best classified as a severe classicism, appearing rational but in fact it was prescriptively formal and abstract. Thus the reasons for Kahn’s industrial aesthetic were abandoned by the Germans when they accepted an aesthetic that claimed to be expressively functional but was in fact a style applied to all building types, regardless of all other considerations.

In the late 1920s seven architects launched the Italian Rationalist Movement, announcing that a “new architecture, true architecture, must emerge from a strict adherence to logic, to rationality.” Their buildings and projects, supposedly born in Italy’s traditions (and in opposition to the bustling but defunct futurists) and in fascism were widely diverse in appearance, many with structural clarity while immodestly betraying the influence of Russian Constructivists, Le Corbusier, and the Bauhaus. Giuseppe Terragni was their more expert apostle through the 1930s.

Then in 1941, a theoretical work was released on antecedents of 20th-century architecture by Siegfried Giedion, Space Time and Architecture. It was a faithful rationalist document in praise of functionalism. Giedion’s intention was to concentrate on “the interrelations with other human activities…[on] architecture, construction, painting, city planning, and science” (1954). This was followed in 1948 by his second seminal study, Mechanization Takes Command, whose title reveals all.

In the decades after midcentury, rationalism became both clarified and distorted. Louis Kahn believed that a building had measurable qualities, that there were ordinate and subordinate spaces with natural hierarchies, that these functional aspects wanted to be defined by their unique form, and that perceptual awareness of architecture was in the orderly arrangement of forms. Supported by his poetic philosophy, these relationships were vigorously exploited by simple volumetric geometry, notably his A.N.Richards Laboratories, Philadelphia (1957–61), the second paradigm of 20th-century rationalism. If we accept that architectural form is shaped by programmatic functions, and this should include social and economic conditions, or by the spirit of its time, or by timeless principles, then the two extremes at midcentury were Kahn’s romantically, picturesquely ordered forms and Mies van der Rohe’s internally preordered forms classically composed. The reaction was the exploitation of form over function and hierarchies that were so apparent in 1950s sensualism and later the work of Arata Isozaki and Morphosis, to cite two examples.

A new neorationalism arose in the 1960s, again in Italy and composed by Fabio Reinhart and Aldo Rossi, among others, who rejected their predecessors. Soon there was the Madrid School, then in Germany architects Mathias Ungers and J.P. Kleihus, and in the United States, architects such as the New York Five, of whom the prolific Richard Meier has since remained the most faithful to original tenets. Again, these architects produced a wide variety of characteristics, none architectonically related, all distinct yet often claiming a mix of rationalistic and existential foundations.

Much of neorationalism was a theoretical twist with the attempt to relate architecture to political theories (usually Marxist) or to social theories, particularly through semiotics, which recognizes that buildings carry meanings (signs) and symbolic overtones, more often than not because of cultural continuity or history. Much of its theory was derived from or instituted in linguistics. Therefore one can understand that the problem of analogies with the complexities of architecture are many, not the least that semiotics (and the earlier structuralism) is evaluative, tending to operate postmortem, therefore only clumsily relevant to the processes inherent in creating architecture let alone to design methodology.

There is something strangely romantic in the architectonic application of those socioeconomic theories. Perhaps this reflects the continuing debate between rationalism and Romanticism, between the ongoing search for objective principles of design with universal application (regardless of complexity or culture, all functions are naturally similar throughout history), and the personal freedom that followed the collapse early in the century or generally agreed principles: witness Expressionism in the 1920s or sensualism in the 1950s or the independent Oscar Niemeyer and Frank O.Gehry.

The house in Riva San Vitalo, Italy (1972–73), by Mario Botta, should send shivers of joy through a rationalist because of its precisely extended square, obvious structure and responding use of materials, consistent vertical organization, functional expression, deceiving formality and careful proportions, all providing a modern clarification of Viollet-le-Duc’s ideas, of Wright’s organic song, and a sensible adaptation of Louis Kahn’s functional geometry.


Sennott R.S. Encyclopedia of twentieth century architecture, Vol.3 (P-Z).  Fitzroy Dearborn., 2005.



LE CORBUSIER (Jeanneret, Charles-Édouard)












Botta, Mario (Switzerland); Brutalism; Constructivism; Corbusier, Le (Jeanneret, Charles-Édouard) (France); Futurism; Giedion, Sigfried (Switzerland); Modernism; Kahn, Albert (United States); Kahn, Louis (United States); Mies van der Rohe, Ludwig (Germany); Perret, Auguste (France); Sullivan, Louis (United States); Terragni, Giuseppe (Italy); Wright, Frank Lloyd (United States)


Collins (1965), Middleton and Watkin, and Gelernter describe or interpret historical, theoretical, and practical parameters. Lesnikowski dis-cusses ideas and illustrates buildings c. 1800 to the present, Banham nicely outlines the transition period c. 1910, and Frampton the century’s varied courses up to the 1980s. Each of the foregoing contains a discussion about rationalism and/or its proponents. Delevoy et al. display verbally and pictorially the transition from Louis Kahn to the so-called neorationalists; antihumanist proposals and baroque fantasies abound. Langmead and Johnson and Collins (1959, on Perret) outline two individual cases, one about Atlantic cross currents prior to c. 1950.

Architectural Design. “Eugène-Emmanuel Viollet-le-Duc 1814–1879,” 50, no. 3/4 (1980) Architectural Design. “From Futurism to Rationalism,” and Peter Dickens, “The Hut and the Machine,” 51, no. 1/2 (1981)

Banham, Reyner, Theory and Design in the First Machine Age, London: Architectural Press, 1960

Collins, Peter, Changing Ideals in Modern Architecture 1750–1950, London: Faber, 1965

Delevoy, Robert, et al., Rational Architecture the Reconstruction of the European City, Bruxelles: Archive d’Architectures Modern, 1978

Frampton, Kenneth, Modern Architecture, a Critical History, 2nd ed., London: Thames and Hudson, 1985 Gelernter, Mark, Sources of Architectural Form: A Critical History of Western Design Theory, Manchester: Manchester University Press, 1995

Giedion, Siegfried, Mechanization Takes Command, New York: Oxford University Press, 1948

Giedion, Siegfried, Space Time and Architecture, the Growth of a New Tradition, Cambridge, Massachusetts: Harvard University Press, 1941, 3rd ed., 1954 Hearn, M.F. (editor), The Architectural Theory of Viollet-le-Duc Readings and Commentary, Cambridge, Massachusetts: MIT Press, 1990

Hoffmann, Donald, “Frank Lloyd Wright and Viollet-le-Duc,” Journal of the Society of Architectural Historians 28 (October 1969) Langmead, Donald and Donald Leslie Johnson, Architectural Excursions. Frank Lloyd Wright, Holland and Europe, Westport, Connecticut: Greenwood, 2000

Lesnikowski, Wojciech G., Rationalism and Romanticism in Architecture, New York: McGraw-Hill, 1982

Middleton, Robin and David Watkin, Neoclassical and Nineteenth Century Architecture, New York: Abrams, 1980

Summerson, John, Heavenly Mansions, New York: Norton, 1963











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