Kiesler’s definition of the term was succinct: ‘the term “correalism” expressed the dynamics of continual interaction between man and his natural and technological environments’ (1939).

In Kiesler’s view, the interaction between tools, needs, and environment was continual and as he repeatedly explained, ‘no tool exists in isolation. Every technological device is coreal: its existence is conditioned by the flux of man’s struggle’ (1939). The connection between human needs and technological invention led him to a critical set of questions. ‘What is a need? How do needs arise? Are they natural or artificial? Are they static or in evolution? A definition of needs has today become of prime importance to the designer of technological environment. Investigations on this crucial point cannot be based upon the study of architecture but must be based on the study of man’ (1939).

The shift of focus onto man and his needs leads to the key insight of Kiesler’s Correalism: ‘Needs are not static: they evolve’. Moreover, only a few of those needs are ‘absolute’ -hunger, thirst, etc. – and even those are largely culturally conditioned. The ‘need’ for comfort by which most environmental technologies are shaped has progressed step-by-step with the devices meant to accommodate its demands. In other words, the aspirations or even luxuries of one generation become the needs of the next, and so drive the progressive advance of innovation.