A Subjective Measure of Complexity

This article presents a quantitative measure of complexity, subjectively understood as a property of the relationship between a system and its observer instead of as a property of the system itself. Within this framework, complexity is quantified by assuming to know the mental categories and the mental model by which a system is represented in the mind of its observer. It is argued that this subjectivist concept of complexity is not in contrast with objective measures of complexity introduced in particular domains, but generalizes complexity to domains where no objective measure is feasible. An extensive numerical example is presented and thoroughly discussed.