Emergence has been widely recognized as a significant phenomenon of visual reasoning in design. Despite its centrality as a cognitive phenomenon, research in emergence currently lacks a comprehensive theoretical foundation. A broadened view of design emergence that adds to the perceptual phenomenon of shape emergence in reflecting the way the design domains are conceptualized is proposed. An expanded theory of emergence in which visual cognition plays an important role is presented. Beginning with an attempt to broaden the perceptual perspectives of shape emergence, the process of cognitive emergence is defined. The duality of related perceptual and cognitive components provides a working basis for conceptualizing visual emergence in design. Antithetical to the idea of accidental emergence, it is proposed that emergence is guided and anticipated. We claim that it is the recognition of visual shapes and images in design that enables emergence. This kind of guidance function in emergence is termed 'anticipated emergence'. We demonstrate how high-level domain knowledge of visual forms can be accommodated as cognitive content, and how this can contribute to establishing a cognitive basis for emergence. An empirical experiment from the domain of architecture is presented.