Robert Venturi’s manifesto, written in 1962, calls for complexity and contradiction in architecture, because human beings are complex and contradictory, but the book provides no formal analysis of architecture. Ambiguity is cited as an important component of the complexity and contradiction of architecture, because architecture “is form and substance-abstract and concrete-and its meaning derives from its interior characteristics,” its deep structure, “and its particular context” (Venturi 1966: 20). The dialectics of form and substance, abstract and concrete, texture and material, result in “oscillating relationships, complex and contradictory,” which are the source of ambiguity and tension. The very fact that an architectural form can contain both a signifier and a signified, like a word in language, results in ambiguity, as ambiguity is a necessary element of language. The dialectics of form and concept and the resulting oscillating reading seem also to have been influenced by the phenomenal transparency of Colin Rowe. The manifesto by Venturi is described as an apology for his own architecture, the best-known example of which is the Residence in Chestnut Hill, Pennsylvania, or the Vanna Venturi House (1962, Figure 6.1), which is an icon of Postmodernist architecture as historicist pastiche. The design for the façade consists of a pediment broken down the middle, below which is a lintel in the center intersected by the trace of an arch, and bands of small windows on either side. The obvious precedent for the house is the Casa del Girasole (1947, Figure 6.2) by Luigi Moretti, on Via Parioli in Rome, where Venturi researched his manifesto. The façade of the Casa del Girasole combines the Classical pediment, the tripartite division of the Renaissance palazzo, and the Five Points of Le Corbusier, including ribbon windows and a roof terrace, in a historicist composition in the tradition of Leon Battista Alberti, who combined the tripartite division of the Florentine palazzo with the Roman orders for the Palazzo Rucellai (Figure 3.1), and a temple front and triumphal arch for the façade of Sant’Andrea in Mantua (Figure 3.2).