Principle-Based Engineering

Abstract

This chapter discusses a new conception of computation. The conception is one of constraints rather than rules. In contrast to the rule-based approach of Turing machines, Post systems and lambda calculus, the constraint-based approach “models” the constraints in operation in the system, and between the system and the environment. There are similarities with Putnam’s idea that “everything is computation” because (1) computation must be “situated” in a profound way, embedded in its environment, but, there is also (2) a move away from the intuitive idea of “algorithm” as a step-by-step procedure, modellling the behaviour of the system in its environment, requiring a mapping of the abstract “algorithm” states to the physical states of “reality.”