3.3.1 March's model: philosophical
The act of synthesis is central to design. Synthesis means bringing things together to make something new, something different from the constituent parts, something synthetic. March's picture of design (Figure 19) describes three types of process that act together in order to create a new design.
The process of production produces an initial design proposal, from many possibilities, that is a candidate to solve the design problem in hand. The process of deduction applies known theories and understanding to predict the performance of a design proposal. The process of induction evaluates a design against specification. Resulting changes and refinements help generate a new design proposal (production again). The cycle repeats, taking a designer towards a solution.
These ideas are intuitively attractive. It is easy to imagine all of these processes taking place in some sort of suitable mix. For example:
Do I build a timber-frame house on my plot of land, or a brick-built house (production of a candidate idea)?
Some calculations of energy efficiency, cost of labour, and a judgement on the resale value leads me to a conventional UK design in brick and glass (deductions about the idea).
Whilst planning a conservatory I hit on the idea of using it to channel warm air into the main living space, so refining the design (induction to further design ideas).
The degree to which each component is present in the mix could vary. Designing an electrical circuit with similar characteristics to a previously designed circuit might only involve the deductive process. By contrast, designing an advanced space vehicle would require a great deal of production.
The temptation to break down design into detailed plans is, however, irresistible.