Classical and non-classical computation

supportive in the design process. For this to be possible, computation must be understood in a broad sense, encompassing both the narrow, digital kind of computation and the more general kind of computation in which objects may only have digital approximations. It is this broad approach that we have adopted. The aspects of computation considered here are representation and process. Representation has to do with the way the objects in a computation are described. Process has to do with the computation itself and the rules that are used to carry it out. Both of these aspects have been approached in alternative ways – either classically or non-classically. These divisions are not hard and fast ones, but soft ones that are blurred at the boundaries. We apply the classical/non-classical distinction because it provides a useful taxonomy both to see what is going on in computation, and to suggest areas for future investigation of importance in design. Certainly, as it is worked out below, the classical/non-classical split in process is already widely appreciated, even if it is not really discrete but more of a continuum. In representation, though, the split is more profound, even if much less appreciated. We are all used to computation in the classical mode – this is what is taught in school – and it takes some shifting of gears to see how computation can be more successfully used in design when representation is non-classical. For this reason, our main emphasis will be on non-classical representation. Any imbalance in presentation, however, is not to reflect importance. All of the categories identified in our taxonomy provide valuable insights in design and computation.