 Education requires simplification, that is, the empiricist notion of abstraction in the face of the complexity of facts. Teaching requires knowing what to leave out, what counts as superfluous detail and accuracy: ‘he who knows best what to omit is the best teacher’ and so ‘to remember simplified pictures is better than to forget accurate figures’ (Neurath 1933/1973, 220 and 1945a, 440). The graphic, visual counterpart of this point constitutes the basis for his design of ISOTYPE icons, by analogy with the method of silhouettes, so popular in Austrian art, as a form of visual abstraction for the communication of information about types or general concepts. The approach was consistent with the empiricist anti-metaphysical spirit and Bauhaus and modernist aesthetic of the rejection of ornament famously advocated by the Viennese architect Adolf Loos in Ornament and Crime (1908) also echoed by Neurath in 1926: ‘the time of ornaments is over’ (recounted by Ernst Niekisch in Neurath 1973, 22).