The central problem considered by architectural theorists is the establishment of a theory of interaction which gives rise to a matrix of the built form. This paper analyses the structure of architectural design education and practice in relation to the theories of H.A. Simon, Richard Llewelyn-Davies, Christopher Alexander, and the subsequent work emanating from W. Hillier, A. Leaman, and J. Musgrove from 1972. It relates the theoretical problems of architecture to Simon's “Design Science”, and also to the paradigm of “intuition” advocated by Llewelyn-Davies at London University.